Battery system and method of controlling connection between battery pack using 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 includes: a battery device including a plurality of battery packs; a first terminal and a second terminal respectively connected to both ends of the battery device; and a battery management system (BMS) configured to derive a plurality of battery pack voltages of the plurality of battery packs based on a plurality of voltage measurement signals received from the plurality of battery packs, determining a voltage across the battery device as a first voltage or a second voltage according to which of the first terminal and the second terminal the driving device is connected to, determining whether the plurality of battery packs are connected 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 whether the plurality of battery packs are connected in parallel or in series. A battery pack to be connected in series among the plurality of battery packs is determined based on the plurality of battery pack voltages.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0186958 filed in the Korean Intellectual Property Office on December 28, 2022, the entire contents of which are incorporated herein by reference.

[0003] The present disclosure relates to a battery system and a method of controlling connections between battery packs using the battery system. Background Art

[0004] The external system connected to the battery system may include a device requiring a voltage level of 400 V for its operation and a device requiring a voltage level of 800 V for its operation. In order for the battery system to charge and discharge the external system, a battery pack connection matching the operating voltage of the device in the external system is required.

[0005] There is a need for a battery system that can charge and discharge from a device having a voltage level of 800V as an operating voltage without connecting a battery pack having a battery pack voltage of 400V and a battery pack having a battery pack voltage of 800V. Summary of the Invention

[0006] Technical issues

[0007] The present disclosure attempts to provide a battery system and a method of controlling connections between battery packs using the battery system, which can be connected to devices with different operating voltages by selecting series-parallel connection relationships between multiple battery packs in a battery system including multiple battery packs having a battery pack voltage corresponding to 400V.

[0008] Technical Solution

[0009] According to one aspect of the present disclosure, a battery system includes: a battery device including multiple battery packs; a first terminal and a second terminal, the first terminal and the second terminal being connected to both ends of the battery device; and a battery management system (BMS), the battery management system deriving multiple battery pack voltages of the multiple battery packs based on multiple voltage measurement signals received from the multiple battery packs, determining the voltage at both ends of the battery device as a first voltage or a second voltage depending on which of the first terminal and the second terminal a driving device is connected to, determining whether to connect the multiple battery packs in parallel or in series based on the voltages at both ends of the battery device, and when the multiple battery packs are connected in series, determining which battery packs among the multiple battery packs to connect in series based on the multiple battery pack voltages.

[0010] The BMS may perform CAN communication with an electronic control unit (ECU) and receive information indicating that a discharge level of the battery device is one of the first voltage and the second voltage from the ECU.

[0011] When a first driving device driven at a voltage level of the first voltage is connected to the first terminal, or when information indicating that the discharge level of the battery device is 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 of the multiple battery packs to both ends of the battery device.

[0012] When a second driving device driven at a voltage level of the second voltage is connected to the second terminal, or when information indicating that the discharge level of the battery device is 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 groups to be connected in series among the multiple battery groups, and connect both ends of the at least one series group to both ends of the battery device.

[0013] When the number of at least one series group is two or more, the BMS can determine two or more series groups so that the difference between the sum of the multiple first battery group voltages of the multiple first battery groups belonging to the first series group among the two or more series groups and the sum of the multiple second battery group voltages of the multiple second battery groups belonging to the second series group among the two or more series groups is less than or equal to a predetermined threshold.

[0014] The BMS can generate a switch control signal that connects the battery groups belonging to each of the two or more series groups in series in series, a switch control signal that connects the positive terminal of each of the two or more series groups in series to the positive terminal of the battery device, and a switch control signal that connects the negative terminal of each of the two or more series groups in series to the negative terminal of the battery device.

[0015] According to another aspect of the present disclosure, a method for connecting between battery packs includes: a battery management system (BMS) connecting the battery device to an external system by connecting to one of a first terminal and a second terminal at both ends of a battery device including multiple battery packs; the BMS determining a voltage at both ends of the battery device as a first voltage or a second voltage depending on which of the first terminal and the second terminal the drive device is connected to; the BMS deriving multiple battery pack voltages of the multiple battery packs based on multiple voltage measurement signals received from the multiple battery packs; determining whether to connect the multiple battery packs in parallel or in series based on the voltages at both ends of the battery device; and when the multiple battery packs are connected in series, determining which battery packs of the multiple battery packs to connect in series based on the multiple battery pack voltages.

[0016] The method may further include performing CAN communication, by the BMS, with an electronic control unit (ECU), and receiving information from the ECU indicating that a discharge level of the battery device is one of the first voltage and the second voltage.

[0017] The method may further include: when a first driving device driven at a voltage level of the first voltage is connected to the first terminal, or when information indicating that the discharge level of the battery device is the first voltage is received from the ECU, determining the voltage across the battery device as the first voltage; and connecting both ends of at least one battery pack of the multiple battery packs to both ends of the battery device.

[0018] The method may further include: when a second driving device driven at a voltage level of the second voltage is connected to the second terminal, or when information indicating that the discharge level of the battery device is the second voltage is received from the ECU, determining the voltage across the battery device as the second voltage; determining at least one series group including two or more battery groups to be connected in series among the multiple battery groups; and connecting both ends of the at least one series group to both ends of the battery device.

[0019] When the number of at least one series group is two or more, determining the at least one series group may also include: determining two or more series groups so that the difference between the sum of the multiple first battery group voltages of the multiple first battery groups belonging to the first series group among the two or more series groups and the sum of the multiple second battery group voltages of the multiple second battery groups belonging to the second series group among the two or more series groups is less than or equal to a predetermined threshold.

[0020] The method may further include generating a switch control signal for connecting the battery groups belonging to each of the two or more series groups in series in series, a switch control signal for connecting the positive terminal of each of the two or more series groups in series to the positive terminal of the battery device, and a switch control signal for connecting the negative terminal of each of the two or more series groups in series to the negative terminal of the battery device.

[0021] Beneficial effects

[0022] According to the present disclosure, the battery system can be efficiently operated by connecting multiple battery packs in parallel when connecting a device requiring a voltage level of 400V for operation and connecting multiple battery packs in series when connecting a device requiring a voltage level of 800V for operation.

[0023] According to the present disclosure, when a battery system is applied to a commercial vehicle, the battery can be used in a direction desired by a user by selecting high output or high capacity according to cargo load and driving distance.

[0024] According to the present disclosure, users of the battery system can charge the battery anywhere they want, whether it is 400V charging or 800V charging.

[0025] According to the present disclosure, the charging speed can be reduced by charging a 400V battery pack at a charging station that outputs 800V capacity.

[0026] According to the present disclosure, an existing 400V battery pack can be converted to 800V and used without manufacturing a separate 800V battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a block diagram schematically illustrating a battery system according to one embodiment.

[0028] Figure 2 yes Figure 1 Example of a battery system.

[0029] Figure 3 yes Figure 1 An example of a battery system including multiple series-connected battery packs.

[0030] Figure 4 is a flowchart of a method for controlling connections between battery packs according to one embodiment. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and identical or similar components are given identical reference numerals and will not be described repeatedly. The suffixes "module" and / or "unit" of the components used in the following description are given or mixed only for the ease of writing the specification, and therefore the suffixes "module" and / or "unit" do not have meanings or roles that distinguish one from another. In addition, when it is determined that a detailed description of known technologies related to the present disclosure may obscure the main points of the present disclosure, these detailed descriptions will be omitted. In addition, it should be understood that the accompanying drawings are provided only to allow easy understanding of the exemplary embodiments of the present disclosure, and the spirit of the present disclosure is not limited to the accompanying drawings, but includes all modifications, equivalents and replacements included in the spirit and scope of the present disclosure.

[0032] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited to these terms. The above terms are used only for the purpose of distinguishing one component from another.

[0033] It should also be understood that the terms “including” or “having” used in this specification specify the presence of the features, numbers, steps, operations, components, parts or their combinations mentioned in this specification, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or their combinations.

[0034] In a component according to one embodiment, a program implemented as an instruction set specifying a control algorithm necessary for controlling other components can be installed in the component to control the other components under specific control conditions. The control component can process input data and stored data according to the installed program to generate output data. The control component may include a nonvolatile memory for storing the program and a memory for storing data.

[0035] Figure 1 is a block diagram schematically illustrating a battery system according to one embodiment.

[0036] refer to Figure 1 The 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 .

[0037] 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. In the following, for the convenience of description, among 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, the switching elements S1_P to S4_P are referred to as positive switching elements, the switching elements S1_N to S4_N are referred to as negative switching elements, and the switching elements S1_2, S1_3, S1_4, S2_3, S2_4 and S3_4 are referred to as series switching elements.

[0038] Each of the plurality of battery packs 101 to 104 may be implemented as two or more battery cells connected in series, a plurality of battery cells having two or more battery cells connected in parallel, or two or more battery cells connected in parallel.

[0039] exist Figure 1 , the number of battery packs 101 to 104 is shown as four, but the present disclosure is not limited thereto, and the battery device 100 may include two or more battery packs.

[0040] The BMS 200 may receive a plurality of voltage measurement signals VS1 to VS8 from the positive and negative electrodes of each of the plurality of battery packs 101 to 104. The BMS 200 may obtain the voltage measurement signal VS1 from the positive electrode of the battery pack 101, and the BMS 200 may obtain the voltage measurement signal VS2 from the negative electrode of the battery pack 101. The BMS 200 may obtain the voltage measurement signal VS3 from the positive electrode of the battery pack 102, and the BMS 200 may obtain the voltage measurement signal VS4 from the negative electrode of the battery pack 102. The BMS 200 may obtain the voltage measurement signal VS5 from the positive electrode of the battery pack 103, and the BMS 200 may obtain the voltage measurement signal VS6 from the negative electrode of the battery pack 103. The BMS 200 may obtain the voltage measurement signal VS7 from the positive electrode of the battery pack 104, and the BMS 200 may obtain the voltage measurement signal VS8 from the negative electrode of the battery pack 104.

[0041] The BMS 200 can measure the battery pack voltage of each of the plurality of battery packs 101 to 104 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 an off state. The BMS 200 can transmit off-level switching control signals SCS1_P to SCS4_P and SCS1_N to SCS4_N to the plurality of positive switching elements S1_P to S4_P and the plurality of negative switching elements S1_N to S4_N, and receive a plurality of voltage measurement signals VS1 to VS8.

[0042] The BMS 200 can derive the stack voltage of each of the plurality of battery stacks 101 to 104 from the plurality of voltage measurement signals VS1 to VS8. The BMS 200 can derive the stack voltage of the battery stack 101 from the voltage measurement signal VS1 and the voltage measurement signal VS2. The BMS 200 can derive the stack voltage of the battery stack 102 from the voltage measurement signal VS3 and the voltage measurement signal VS4. The BMS 200 can derive the stack voltage of the battery stack 103 from the voltage measurement signal VS5 and the voltage measurement signal VS6. The BMS 200 can derive the stack voltage of the battery stack 104 from the voltage measurement signal VS7 and the voltage measurement signal VS8.

[0043] The BMS 200 may receive battery information indicating current, voltage, temperature, etc. of the plurality of battery packs 101 to 104 from the battery device 100. The BMS 200 may estimate a battery pack capacity of each of the plurality of battery packs 101 to 104 based on the battery information.

[0044] One end of the switch element S1_P is connected to the positive terminal of the battery pack 101, and the other end of the switch element S1_P is connected to one end of the relays 311 and 321. One end of the switch element S1_N is connected to the negative terminal of the battery pack 101, and the other end of the switch element S1_N is connected to one end of the relays 312 and 322.

[0045] One end of the switch element S2_P is connected to the positive terminal of the battery pack 102, and the other end of the switch element S2_P is connected to one end of the relays 311 and 321. One end of the switch element S2_N is connected to the negative terminal of the battery pack 102, and the other end of the switch element S2_N is connected to one end of the relays 312 and 322.

[0046] One end of the switch element S3_P is connected to the positive terminal of the battery pack 103, and the other end of the switch element S3_P is connected to one end of the relays 311 and 321. One end of the switch element S3_N is connected to the negative terminal of the battery pack 103, and the other end of the switch element S3_N is connected to one end of the relays 312 and 322.

[0047] One end of the switch element S4_P is connected to the positive terminal of the battery pack 104, and the other end of the switch element S4_P is connected to one end of the relays 311 and 321. One end of the switch element S4_N is connected to the negative terminal of the battery pack 104, and the other end of the switch element S4_N is connected to one end of the relays 312 and 322.

[0048] 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 an on state, the plurality of battery packs 101 to 104 may be connected in parallel.

[0049] 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 101 to 104 that can be connected in series. For example, when 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] One end of the switch element S2_4 is connected to the negative electrode of the battery pack 102, and the other end of the switch element S2_4 is connected to the positive electrode of the battery pack 104. When the switch element S2_4 is in an on state, the battery pack 102 and the battery pack 104 may be connected in series.

[0055] One end of the switch element S3_4 is connected to the negative electrode of the battery pack 103, and the other end of the switch element S2_4 is connected to the positive electrode of the battery pack 104. When the switch element S3_4 is in an on state, the battery pack 103 and the battery pack 104 can be connected in series.

[0056] When at least one of the series switching elements S1_2 , S1_3 , S1_4 , S2_3 , S2_4 , and S3_4 is in an on state, corresponding battery packs among the plurality of battery packs 101 to 104 may be connected in series.

[0057] Closure and opening 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 are controlled according to 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 the BMS 200 .

[0058] 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 the external system. The plurality of relays 311, 312, 321, and 322 can be controlled to be closed and opened according to relay control signals RCS11, RCS12, RCS21, and RCS22 supplied from the BMS 200.

[0059] The battery system 1 can be connected to an external system, which can be the first drive device 21 or the second drive device 22 .

[0060] The power supply voltage level required for the operation of the first driving device 21 may be the voltage level of the first voltage V1. The power supply voltage level required for the operation of the second driving device 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.

[0061] The battery pack voltage of each of the plurality of battery packs 101 to 104 may be a voltage level within a predetermined range based on the first voltage V1 .

[0062] Each of the first drive device 21 and the second drive device 22 may include at least one power conversion device, such as an inverter or a converter, connected to a charger and a load. Figure 1, each of the first driving device 21 and the second driving device 22 is shown as one, but the present disclosure is not limited thereto. The first driving device 21 and the second driving device 22 may be one or more driving devices.

[0063] When the relays 311 and 312 are in the on state, the battery system 1 may be connected to the first driving device 21 through the first terminals P1+ and P1-. The battery system 1 may perform a charging or discharging operation during a period when the relays 311 and 312 are in the on state.

[0064] When the first drive device 21 is a power conversion device connected to a charger, during the period when relays 311 and 312 are in an on state, the first terminals P1+ and P1- of the battery system 1 can be connected to the power conversion device to receive power from the charger, thereby allowing the first terminals P1+ and P1- of the battery system 1 to be charged. When the first drive device 21 is a load, during the period when relays 311 and 312 are in an on state, the first terminals P1+ and P1- of the battery system 1 can be connected to the load to release power provided by at least one of the battery packs 101 to 104 through the load.

[0065] When the relays 321 and 322 are in the on state, the battery system 1 may be connected to the second driving device 22 through the second terminals P2+ and P2-. The battery system 1 may perform a charging or discharging operation during a period when the relays 321 and 322 are in the on state.

[0066] When the second drive device 22 is a power conversion device connected to a charger, the second terminals P2+ and P2- of the battery system 1 can be connected to the power conversion device during the period when the relays 321 and 322 are in the on state to receive power from the charger, thereby allowing the second terminals P2+ and P2- of the battery system 1 to be charged. When the second drive device 22 is a load, the second terminals P2+ and P2- of the battery system 1 can be connected to the load during the period when the relays 321 and 322 are in the on state to release power provided by at least one of the battery packs 101 to 104 through the load.

[0067] A device that controls the operation of the vehicle (e.g., an electronic control unit (ECU) 3) may receive a battery status signal (BSS) transmitted from the BMS 200 and transmit information input from a user of the vehicle to the BMS 200. In this case, the ECU 3 and the BMS 200 may transmit and receive necessary information via CAN communication. The information input from the user of the vehicle may include a signal indicating that the discharge level of the battery device 100 is one of a first voltage V1 and a second voltage V2 according to the user's selection.

[0068] The BMS 200 may pre-store information indicating the rated voltage of the first terminals P1+ and P1- to which the first drive device 21 is connected and the rated voltage of the second terminals P2+ and P2- to which the second drive device 22 is connected. Alternatively, the BMS 200 may receive information indicating the rated voltage of the first terminals P1+ and P1- and the rated voltage of the second terminals P2+ and P2- from the vehicle's ECU 3. The BMS 200 may receive information from the ECU 3 regarding whether the drive device is connected to each of the first terminals P1+ and P1- and the second terminals P2+ and P2-. Alternatively, the BMS 200 may be electrically connected to each of the first terminals P1+ and P1- and the second terminals P2+ and P2- to detect whether the drive device is connected to each terminal. The BMS 200 may be implemented in various ways to detect whether the drive device is connected to each terminal, and if necessary, a separate circuit may be provided to determine whether the drive device is connected to each terminal.

[0069] The BMS 200 may determine to connect at least one of the first drive device 21 and the second drive device 22 to the battery system 1. When the first drive device 21 is determined to be connected, the BMS 200 may generate conduction-level relay control signals RCS11 and RCS12 and transmit the generated conduction-level relay control signals RCS11 and RCS12 to the relays 311 and 312. When the second drive device 22 is determined to be connected, the BMS 200 may generate conduction-level relay control signals RCS21 and RCS22 and transmit the generated conduction-level relay control signals RCS21 and RCS22 to the relays 321 and 322.

[0070] The BMS 200 determines the voltages at both ends P100+ and P100- of the battery device 100 based on the drive device connected to the battery device 100 among the first drive device 21 and the second drive device 22. When the determined voltages at both ends are the second voltage V2, the BMS 200 can determine which battery packs among the plurality of battery packs 101 to 104 are connected in series, and whether to connect the battery packs connected in series in parallel. Hereinafter, for ease of description, the battery packs among the plurality of battery packs that the BMS 200 has determined to be connected in series in response to the second voltage V2 are referred to as series groups.

[0071] The BMS 200 may generate on-level or off-level 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 according to the determined configuration of the battery packs to be connected in series, to control the operation of the 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 ease of description, the operation of the BMS 200 controlling the switching operation 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 is referred to as a "switching control operation."

[0072] The BMS 200 may generate a switching control signal SCS1_P and transmit the generated switching control signal SCS1_P to the switching element S1_P. The BMS 200 may generate a switching control signal SCS2_P and transmit the generated switching control signal SCS2_P to the switching element S2_P. The BMS 200 may generate a switching control signal SCS3_P and transmit the generated switching control signal SCS3_P to the switching element S3_P. The BMS 200 may generate a switching control signal SCS4_P and transmit the generated switching control signal SCS4_P to the switching element S4_P. The BMS 200 may generate a switching control signal SCS1_N and transmit the generated switching control signal SCS1_N to the switching element S1_N. The BMS 200 may generate a switching control signal SCS2_N and transmit the generated switching control signal SCS2_N to the switching element S2_N. The BMS 200 may generate a switching control signal SCS3_N and transmit the generated switching control signal SCS3_N to the switching element S3_N. The BMS 200 may generate a switching control signal SCS4_N and transmit the generated switching control signal SCS4_N to the switching element S4_N.

[0073] The BMS 200 may generate a switching control signal SCS1_2 and transmit the generated switching control signal SCS1_2 to the switching element S1_2. The BMS 200 may generate a switching control signal SCS1_3 and transmit the generated switching control signal SCS1_3 to the switching element S1_3. The BMS 200 may generate a switching control signal SCS1_4 and transmit the generated switching control signal SCS1_4 to the switching element S1_4. The BMS 200 may generate a switching control signal SCS2_3 and transmit the generated switching control signal SCS2_3 to the switching element S2_3. The BMS 200 may generate a switching control signal SCS2_4 and transmit the generated switching control signal SCS2_4 to the switching element S2_4. The BMS 200 may generate a switching control signal SCS3_4 and transmit the generated switching control signal SCS3_4 to the switching element S3_4.

[0074] When the first drive device 21 or the second drive device 22 is a power conversion device connected to a charger, the BMS 200 may control the switching operation according to which of the first terminals P1+ and P1- and the second terminals P2+ and P2- the drive device is connected to, so that the voltage across the two ends P100+ and P100- of the battery device 100 corresponds to one of the first voltage V1 and the second voltage V2.

[0075] When the first drive device 21 or the second drive device 22 is a load, the BMS 200 can control the switching operation based on information received from the ECU 3 so that the voltage across the terminals P100+ and P100- of the battery device 100 corresponds to one of the first voltage V1 and the second voltage V2. For example, a user can select a discharge level for the battery device 100 connected to the vehicle from the first voltage V1 and the second voltage V2, and input the selected information to the ECU 3 through the vehicle. The ECU 3 can 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 can transmit information indicating that the first voltage V1 has been selected to the BMS 200.

[0076] When the battery device 100 is charged by connecting the first driving device 21 to the first terminals P1+ and P1-, or when the discharge level of the battery device 100 selected by the user is the first voltage V1, the BMS 200 can control the switch operation so that the voltage across the two terminals P100+ and 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 can control the switch operation so that the voltage across the two terminals P100+ and P100- of the battery device 100 corresponds to the first voltage V1.

[0077] When the battery device 100 is charged by connecting the second driving device 22 to the second terminals P2+ and P2-, or when the discharge level of the battery device 100 selected by the user is the second voltage V2, the BMS 200 can control the switch operation so that the voltage across the two ends P100+ and P100- of the battery device 100 corresponds to the second voltage V2.

[0078] The BMS 200 may control 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 based on the battery pack voltage and / or battery pack capacity of each of the plurality of battery packs 101 to 104. Alternatively, the BMS 200 may control 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. Hereinafter, for convenience of description, the BMS 200 controls the switching operation 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 battery pack voltage of each of the plurality of battery packs 101 to 104 .

[0079] When the plurality of relays 311 and 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 the terminals P100+ and P100- of the battery device 100 as the first voltage V1. This is because the first voltage V1 corresponds to the power level required for the operation of the first driving device 21. Since the battery pack voltage of each of the plurality of battery packs 101 to 104 corresponds to the first voltage V1, the BMS 200 may determine at least one battery pack among the plurality of battery packs 101 to 104 to be connected to the terminals P100+ and P100- of the battery device 100.

[0080] In the following, reference will be made to Figure 2 The BMS 200 is described as a switch control operation in which the two terminals P100+ and P100 − of the battery device 100 correspond to the first voltage V1 .

[0081] Figure 2 yes Figure 1 Example of a battery system.

[0082] The BMS 200 may determine at least one battery pack among the plurality of battery packs 101 to 104 to be connected to the terminals P100+ and P100- of the battery device 100 based on the battery pack voltage of each of the plurality of battery packs 101 to 104. The BMS 200 may store a first reference voltage range that is a normal range of the voltage at the terminals P100+ and P100- of the battery device 100 in response to the first voltage. The BMS 200 may determine at least one battery pack whose voltage at the terminals P100+ and P100- of the battery device 100 is within the first reference voltage range.

[0083] 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.

[0084] exist Figure 2 In the example of FIG. 1 , the BMS 200 connects the battery pack 101 , the battery pack 103 , and the battery pack 104 among the plurality of battery packs 101 to 104 at both ends P100+ and P100 − of the battery device 100 .

[0085] 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 corresponding to the battery pack to be connected to both ends P100+ and P100- of the battery device 100, among the plurality of positive switching elements S1_P to S4_P and the plurality of negative switching elements S1_N to S4_N. Figure 2 In the example, BMS200 can turn off multiple series switching elements S1_2, S1_3, S1_4, S2_3, S2_4 and S3_4, and turn on three positive switching elements S1_P, S3_P and S4_P and three negative switching elements S1_N, S3_N and S4_N corresponding to battery pack 101, battery pack 103 and battery pack 104.

[0086] The BMS 200 may generate on-level switch control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N, and SCS4_N, and transmit the generated on-level switch control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N, and SCS4_N to a plurality of switching elements S1_P, S3_P, S4_P, S1_N, S3_N, and S4_N. Among the plurality of switch 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 except the on-level switch control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N, and SCS4_N may be off-level. Hereinafter, for convenience of description, among the plurality of switch 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, switch control signals other than those designated as on-levels are assumed to be off-levels.

[0087] exist Figure 1 , when the plurality of relays 321 and 322 are turned on and the second drive device 22 is connected to the battery device 100, the BMS 200 may determine the voltage across the terminals P100+ and P100- of the battery device 100 as the second voltage V2. This is because the second voltage V2 corresponds to the power level required for the operation of the second drive device 22. Since the voltage across the series group of two battery groups connected in series among the plurality of battery groups 101 to 104 is a voltage corresponding to the second voltage V2, the BMS 200 may determine at least one series group among the plurality of battery groups 101 to 104 to be connected to the terminals P100+ and P100- of the battery device 100. When there are two or more series groups, the BMS 200 may control the two or more series groups to be connected in parallel.

[0088] In the following, reference will be made to Figure 3 The BMS 200 is described as a switch control operation in which the two terminals P100+ and P100 − of the battery device 100 correspond to the first voltage V1 .

[0089] Figure 3 yes Figure 1 An example of a battery system including multiple series-connected battery packs.

[0090] The BMS 200 may determine at least one series connection group among the plurality of battery groups 101 to 104 to be connected to the terminals P100+ and P100- of the battery device 100 based on the battery group voltage of each of the plurality of battery groups 101 to 104. The BMS 200 may pre-store a second reference voltage range that is a normal range of voltages at the terminals P100+ and P100- of the battery device 100 in response to the second voltage. The BMS 200 may determine at least one series connection group whose voltages at the terminals P100+ and P100- of the battery device 100 are within the second reference voltage range.

[0091] 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.

[0092] In this specification, the number of battery packs belonging to the series group is described as two, but the present disclosure is not limited thereto. The BMS 200 may determine the number of battery packs corresponding to the value obtained by dividing the second voltage V2 by the first voltage V1 as the series group.

[0093] The BMS 200 may turn on the switching elements connected between two battery packs belonging to the 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 the switching elements connected to the 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 the switching elements connected to the 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.

[0094] In order for the BMS 200 to control the switching operation so that the voltages across both ends P100+ and P100 − of the battery device 100 correspond to the second voltage V2 , the battery groups belonging to each of the at least one series group may be determined.

[0095] The following description assumes that the battery pack voltage of the battery pack 101 is 360V, the battery pack voltage of the battery pack 102 is 370V, the battery pack voltage of the battery pack 103 is 380V, and the battery pack voltage of the battery pack 104 is 390V.

[0096] The BMS 200 may derive voltages across each of the at least one series group by considering battery pack voltages of battery packs belonging to each of the at least one series group.

[0097] When there are two or more series groups, the BMS 200 should determine the series group in which the potential difference between the voltage across one of the two or more series groups and the voltage across another of the two or more series groups is less than or equal to a predetermined threshold value. For example, the predetermined threshold value may be 20V.

[0098] When the voltage difference between two or more series-connected groups is large, an inrush current may be generated during operation when the battery device 100 is connected to the first driving device 21 or the second driving device 22. This is because when an inrush current is generated, a shock may occur in the plurality of battery groups 101 to 104 or components within the battery system 1.

[0099] Considering the battery pack voltage of each of the plurality of battery packs 101 to 104, the BMS 200 may determine battery packs 101 and 104 as a first series pack, and battery packs 102 and 103 as a second series pack. The voltage across the first series pack is V = 360 + 390 = 750 (V). The voltage across the second series pack is V = 370 + 380 = 750 (V).

[0100] The BMS 200 may connect a first series group including the battery group 101 and the battery group 104 among the plurality of battery groups 101 to 104 and a second series group including the battery group 102 and the battery group 103 to both ends P100+ and P100 − of the battery device 100 .

[0101] The BMS 200 may generate an on-level switch control signal SCS1_4 and transmit the generated on-level switch control signal SCS1_4 to the switch element S1_4 to connect the battery packs 101 and 104 belonging to the first series group in series. The BMS 200 may generate an on-level switch control signal SCS2_3 and transmit the generated on-level switch control signal SCS2_3 to the switch element S2_3 to connect the battery packs 102 and 103 belonging to the second series group in series. Among the plurality of switch control signals SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4, and SCS3_4, the switch control signals other than the switch control signal SCS1_4 and the switch control signal SCS2_3 may be at an off level.

[0102] The BMS 200 may generate on-level switch control signals SCS1_P and SCS2_P to connect the positive terminals of the first and second series groups to the positive terminal P100+ of the battery device 100, and transmit the generated on-level switch control signals SCS1_P and SCS2_P to the switching elements S1_P and S2_P. The BMS 200 may generate on-level switch control signals SCS3_N and SCS4_N to connect the negative terminals of the first and second series groups to the negative terminal P100- of the battery device 100, and transmit the generated on-level switch control signals SCS3_N and SCS4_N to the switching elements S3_N and S4_N. Among the plurality of switch control signals SCS1_P to SCS4_P, the remaining switch control signals except for the switch control signals SCS1_P and SCS2_P may be at an off level. Among the plurality of switch control signals SCS1_N to SCS4_N, the remaining switch control signals except the switch control signals SCS3_N and SCS4_N may be at a turn-off level.

[0103] Reference Figure 3 , the first series group (the group in which battery group 101 and battery group 104 are connected in series) and the second series group (the group in which battery group 102 and battery group 103 are connected in series) can be connected in parallel to the two ends P100+ and P100- of the battery device 100 according to the switch control operation.

[0104] The voltage across both ends of the first series group and the second series group may correspond to a voltage level of the second voltage V2 required for operation of the second driving device 22 .

[0105] Figure 4 is a flowchart of a method for controlling connections between battery packs according to one embodiment.

[0106] Hereinafter, descriptions overlapping with the above description during operation of the BMS 200 may be omitted.

[0107] The battery system 1 can be connected to an external system of the first drive device 21 or the second drive device 22 (S100). The BMS 200 can connect the battery device 100 to the first drive device 21 or the second drive device 22 through a plurality of relays 311, 312, 321, and 322. The BMS 200 can transmit conduction relay control signals RCS11 and RCS12 to the relays 311 and 312 to connect the battery device 100 to the first drive device 21 through the terminals P1+ and P1-. Alternatively, the BMS 200 can transmit conduction level relay control signals RCS21 and RCS22 to the relays 321 and 322 to connect the battery device 100 to the second drive device 22 through the terminals P2+ and P2-.

[0108] The BMS 200 may determine whether a voltage at both ends P100+ and P100 − of the battery device 100 is the first voltage V1 or the second voltage V2 ( S200 ).

[0109] When the first drive device 21 or the second drive device 22 is a power conversion device connected to a charger, depending on the terminals to which the drive device is connected among the first terminals P1+ and P1- and the second terminals P2+ and P2-, and when the first drive device 21 or the second drive device 22 is a load, the BMS 200 can determine the voltages across P100+ and P100- of the battery device 100 based on information received from the ECU 3.

[0110] In step S200, when the voltage across both ends P100+ and P100- of the battery device 100 is the first voltage V1, the BMS 200 may connect one or two or more battery packs among the plurality of battery packs 101 to 104 in parallel to both ends P100+ and P100- of the battery device 100 (S300). The BMS 200 may determine at least one battery pack to be connected to both ends P100+ and P100- of the battery device 100 based on the battery pack voltage of each of the plurality of battery packs 101 to 104.

[0111] After step S300, the BMS 200 may perform a switching control operation on a switch corresponding to at least one battery pack determined to be connected to both ends P100+ and P100- of the battery device 100 (S400). Figure 2 In the example, BMS200 can generate on-level switching control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N and SCS4_N, and transmit the generated on-level switching control signals SCS1_P, SCS3_P, SCS4_P, SCS1_N, SCS3_N and SCS4_N to multiple switching elements S1_P, S3_P, S4_P, S1_N, S3_N and S4_N.

[0112] When the voltage of both ends P100+ and P100- of the battery device 100 is the second voltage V2 in step S200, the BMS 200 may determine at least one series group to be connected to both ends P100+ and P100- of the battery device 100 (S500).

[0113] The BMS 200 may determine a battery group belonging to each of the at least one series-connected group among the plurality of battery groups 101 to 104 based on the battery group voltage of each of the plurality of battery groups 101 to 104. When there are two or more series-connected groups, the BMS 200 may determine a battery group belonging to each of the plurality of series-connected groups such that a voltage difference between voltages at both ends of the two or more series-connected groups is less than or equal to a predetermined threshold.

[0114] After step S500, the BMS 200 may perform a switching control operation on switches corresponding to at least one series group determined to be connected to both ends P100+ and P100- of the battery device 100 (S600). Figure 3 In the example, BMS200 can generate on-level switch control signals SCS1_4, SCS2_3, SCS1_P, SCS2_P, SCS4_N and SCS3_N, and transmit the generated on-level switch control signals SCS1_4, SCS2_3, SCS1_P, SCS2_P, SCS4_N and SCS3_N to multiple switching elements S1_4, S2_3, S1_P, S2_P, S3_N and S4_N.

[0115] According to one embodiment, the BMS 200 may adjust the voltages at both ends 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 battery packs belonging to the plurality of series-connected groups may be determined such that a voltage difference between the voltages at both ends of the plurality of series-connected groups is less than or equal to a predetermined threshold.

[0116] Although the embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements made by those of ordinary skill in the art to which the present disclosure pertains belong to the scope of the present disclosure.

Claims

1. A battery system, comprising: a battery device comprising a plurality of battery packs; a first terminal and a second terminal, wherein the first terminal and the second terminal are connected to two ends of the battery device; as well as A battery management system BMS, the BMS deriving a plurality of battery pack voltages of the plurality of battery packs based on a plurality of voltage measurement signals received from the plurality of battery packs, determining a voltage across the battery device as a first voltage or a second voltage depending on to which of the first terminal and the second terminal a drive device is connected, 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 among the plurality of battery packs to connect in series based on the plurality of battery pack voltages.

2. The battery system according to claim 1, wherein: The BMS performs CAN communication with an electronic control unit ECU and receives information indicating that a discharge level of the battery device is one of the first voltage and the second voltage from the ECU.

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

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

5. The battery system according to claim 4, wherein: When the number of the at least one series connection group is two or more, The BMS determines two or more series groups so that a difference between a sum of a plurality of first battery group voltages of a plurality of first battery groups belonging to a first series group among the two or more series groups and a sum of a plurality of second battery group voltages of a plurality of second battery groups belonging to a second series group among the two or more series groups is less than or equal to a predetermined threshold.

6. The battery system according to claim 5, wherein: The BMS generates a switch control signal for connecting the battery groups belonging to each of the two or more series groups in series in series, a switch control signal for connecting the positive terminal of each of the two or more series groups in series to the positive terminal of the battery device, and a switch control signal for connecting the negative terminal of each of the two or more series groups in series to the negative terminal of the battery device.

7. A method for controlling connections between battery packs, the method comprising the steps of: connecting the battery device including a plurality of battery packs to an external system by a battery management system (BMS) through one of a first terminal and 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 depending on which of the first terminal and the second terminal a driving device is connected to; deriving, by the BMS, a plurality of battery pack voltages of 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 voltages across the battery device; as well as When the plurality of battery packs are connected in series, which battery packs among the plurality of battery packs are to be connected in series is determined based on the plurality of battery pack voltages.

8. The method according to claim 7, further comprising the steps of: The BMS performs CAN communication with an electronic control unit (ECU), and receives information indicating that the discharge level of the battery device is one of the first voltage and the second voltage from the ECU.

9. The method according to claim 8, further comprising the steps of: When a first driving device driven at the first voltage level is connected to the first terminal, or when information indicating that the discharge level of the battery device is the first voltage is received from the ECU, determining that the voltage across both ends of the battery device is the first voltage; and Both ends of at least one battery pack among the plurality of battery packs are connected to both ends of the battery device.

10. The method according to claim 8, further comprising the steps of: When a second driving device driven at the second voltage level is connected to the second terminal, or when information indicating that the discharge level of the battery device is the second voltage is received from the ECU, determining that the voltage across both ends of the battery device is the second voltage; determining at least one series group including two or more battery groups to be connected in series among the plurality of battery groups; and Both ends of the at least one series connection are connected to both ends of the battery device.

11. The method according to claim 10, wherein: When the number of at least one series group is two or more, The step of determining the at least one series group further comprises: Two or more series groups are determined so that a difference between a sum of a plurality of first battery group voltages of a plurality of first battery groups belonging to a first series group among the two or more series groups and a sum of a plurality of second battery group voltages of a plurality of second battery groups belonging to a second series group among the two or more series groups is less than or equal to a predetermined threshold.

12. The method according to claim 11, further comprising the steps of: The BMS generates a switch control signal for connecting the battery groups belonging to each of the two or more series groups in series in series, a switch control signal for connecting the positive terminal of each of the two or more series groups in series to the positive terminal of the battery device, and a switch control signal for connecting the negative terminal of each of the two or more series groups in series to the negative terminal of the battery device.

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