Battery system and method for controlling the 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 the contents disclosed in the literature of the Korean patent application are included as part of this specification.

[0002] This disclosure relates to a battery system and a connection control method between battery packs using the same.

Background Art

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

[0004] There is a need for a battery system that can charge and discharge from a device with an operating voltage of 800V without connecting a battery pack with a pack voltage of 400V and a battery pack with a pack voltage of 800V respectively.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a battery system including a plurality of battery packs having a pack voltage corresponding to 400V, a battery system capable of selecting a series - parallel connection relationship between the plurality of battery packs and connecting to devices with different operating voltages, and a connection control method between battery packs using the same are provided.

Means for Solving the Problems

[0006] A battery system according to one aspect of the present invention includes a battery device including a plurality of battery packs, first and second terminals connected to both ends of the battery device, 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 at both ends of the battery device as a first voltage or a second voltage depending on which of the first and second terminals a drive device is connected to, determines whether or not to connect the plurality of battery packs in parallel or in series based on the voltage at both ends of the battery device, and, if the plurality of battery packs are connected in series, determines which of the plurality of battery packs to be connected in series based on the plurality of pack voltages.

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

[0008] If a first drive device driven at the voltage level of the first voltage is connected to the first terminal, or if the BMS receives information from the ECU indicating the discharge level of the battery device as the first voltage, the BMS may determine the voltage across both ends of 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] If a second drive unit driven at the voltage level of the second voltage is connected to the second terminal, or if the BMS receives information from the ECU indicating the discharge level of the battery device as the second voltage, the BMS may determine the voltage across both ends of the battery device as the second voltage, determine at least one series group from the plurality of battery packs including two or more battery packs connected in series, and connect both ends of the at least one series group to both ends of the battery device.

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

[0011] The BMS may generate 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.

[0012] A battery pack coupling control method 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; the BMS determining the voltages at both ends of the battery device as a first voltage or a second voltage depending on which of the first and second terminals a drive device is connected to; 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 voltages at both ends of 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 BMS may further include the step of communicating with an ECU (Electronic Control Unit) via CAN and receiving information from the ECU indicating the discharge level of the battery device as either the first voltage or the second voltage.

[0014] If a first drive device driven at the voltage level of the first voltage is connected to the first terminal, or if information is received from the ECU indicating the discharge level of the battery device with the first voltage, the steps may further include determining the voltage at both ends of 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] If a second drive device driven at the voltage level of the second voltage is connected to the second terminal, or if information is received from the ECU indicating that the discharge level of the battery device is the second voltage, the steps may further include determining the voltage at both ends of the battery device as the second voltage, determining at least one series group from among the plurality of battery packs that includes two or more battery packs connected in series, and connecting both ends of the at least one series group to both ends of the battery device.

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

[0017] The BMS may further include the step of 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. [Effects of the Invention]

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

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

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

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

[0022] According to an embodiment of the present invention, without separately creating an 800V battery pack, an existing 400V battery pack can be switched to 800V and utilized.

Brief Description of the Drawings

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

[0026] In this application, terms such as "including" or "having" are used to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that they do not preclude the presence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof in advance.

[0027] Among the configurations according to an embodiment, in a configuration that controls other configurations under specific control conditions, an implementation program may be installed as a set of instruction words that embody the control algorithm necessary to control the other configurations. The control configuration can process input data and stored data according to the installed program and generate output data. The control configuration may include a non-volatile memory for storing the program and a memory for storing data.

[0028] Figure 1 is a schematic block diagram showing a battery system according to one embodiment.

[0029] Referring to Figure 1, the battery system 1 may include a battery device 100, a battery management system (BMS) 200, and a number 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 the sake of explanation, 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, switching elements S1_P to S4_P will be referred to as positive electrode switching elements, switching elements S1_N to S4_N will be referred to as negative electrode 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 battery packs 101 to 104 may be implemented as two or more battery cells connected in series, multiple battery cells consisting of two or more battery cells connected in parallel and connected in series, or two or more battery cells connected in parallel.

[0032] Figure 1 shows a case where there are four battery packs 101 to 104, but the present invention is not limited to this, and the battery device 100 may include two or more battery packs.

[0033] The BMS200 may receive multiple voltage measurement signals VS1 to VS8 from the positive and negative terminals of each of the multiple battery packs 101 to 104. The BMS200 may acquire voltage measurement signal VS1 from the positive terminal of battery pack 101, and the BMS200 may acquire voltage measurement signal VS2 from the negative terminal of battery pack 101. The BMS200 may acquire voltage measurement signal VS3 from the positive terminal of battery pack 102, and the BMS200 may acquire voltage measurement signal VS4 from the negative terminal of battery pack 102. The BMS200 may acquire voltage measurement signal VS5 from the positive terminal of battery pack 103, and the BMS200 may acquire voltage measurement signal VS6 from the negative terminal of battery pack 103. The BMS200 may acquire voltage measurement signal VS7 from the positive terminal of battery pack 104, and the BMS200 may acquire voltage measurement signal VS8 from the negative terminal of battery pack 104.

[0034] The BMS200 may measure the pack voltage of each of the battery packs 101 to 104 when the multiple positive switching elements S1_P to S4_P and the multiple negative switching elements S1_N to S4_N are in the off state. The BMS200 may transmit off-level switching control signals SCS1_P to SCS4_P and SCS1_N to SCS4_N to the multiple positive switching elements S1_P to S4_P and the multiple negative switching elements S1_N to S4_N, and receive multiple voltage measurement signals VS1 to VS8.

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

[0036] The BMS200 may receive battery information from the battery device 100, including current, voltage, temperature, etc., for multiple battery packs 101 to 104. Based on the battery information, the BMS200 may estimate the capacity of each of the multiple battery packs 101 to 104.

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

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

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

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

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

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

[0043] One end of the switching element S1_2 is connected to the negative terminal of the battery pack 101, and the other end of the switching element S1_2 is connected to the positive terminal of the battery pack 102. When the switching element S1_2 is in the 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 terminal of the battery pack 101, and the other end of the switching element S1_3 is connected to the positive terminal of the battery pack 103. When the switching element S1_3 is in the 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 terminal of the battery pack 101, and the other end of the switching element S1_4 is connected to the positive terminal of the battery pack 104. When the switching element S1_4 is in the 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 terminal of the battery pack 102, and the other end of the switching element S2_3 is connected to the positive terminal of the battery pack 103. When the switching element S2_3 is in the 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 terminal of the battery pack 102, and the other end of the switching element S2_4 is connected to the positive terminal of the battery pack 104. When the switching element S2_4 is in the 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 terminal of the battery pack 103, and the other end of the switching element S3_4 is connected to the positive terminal of the battery pack 104. When the switching element S3_4 is in the ON state, the battery pack 103 and the battery pack 104 may be connected in series.

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

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

[0051] One end of each of the relays 311, 312, 321, and 322 is connected to the battery device 100, and the other end of each of the relays 311, 312, 321, and 322 is connected to at least one configuration in an external system. The closing and opening of the relays 311, 312, 321, and 322 may be controlled by relay control signals RCS11, RCS12, RCS21, and RCS22 supplied from the BMS200.

[0052] The battery system 1 may be connected to an external system. The external system may be the first drive unit 21 or the second drive unit 22.

[0053] The power supply voltage level required for the operation of the first drive unit 21 may be the voltage level of the first voltage V1. The power supply voltage level required for the operation of the second drive unit 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 multiple battery packs 101 to 104 may be within a predetermined voltage range with respect to the first voltage V1.

[0055] Each of the first drive unit 21 and the second drive unit 22 may include at least one of a load such as an inverter or converter and a power conversion device connected to a charger. In Figure 1, one first and one second drive unit 21 and 22 are shown, but the present invention is not limited thereto. The first and second drive units 21 and 22 may be one or more drive units.

[0056] When relays 311 and 312 are ON, the battery system 1 may be connected to the first drive unit 21 via the first terminals P1+ and P1-. While relays 311 and 312 are ON, the battery system 1 may perform charging or discharging operations.

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

[0058] When relays 321 and 322 are ON, the battery system 1 may be connected to the second drive unit 22 via the second terminals P2+ and P2-. While relays 321 and 322 are ON, the battery system 1 may perform charging or discharging operations.

[0059] If the second drive unit 22 is a power converter connected to a charger, while relays 321 and 322 are ON, the second terminals P2+ and P2- of the battery system 1 may be connected to the power converter and charged by receiving power from the charger. If the second drive unit 22 is a load, while relays 321 and 322 are ON, the second terminals P2+ and P2- of the battery system 1 may be connected to the load, and power supplied by at least one of the multiple battery packs 101 to 104 may be discharged through the load.

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

[0061] The BMS200 may have pre-stored information indicating the rated voltages of the first terminals P1+ and P1- to which the first drive unit 21 is connected, and the rated voltages of the second terminals P2+ and P2- to which the second drive unit 22 is connected. Alternatively, the BMS200 may receive information indicating the rated voltages of the first terminals P1+ and P1- and the rated voltages of the second terminals P2+ and P2- from the vehicle's ECU3. The BMS200 may also receive information from the ECU3 regarding whether or not a drive unit is connected to each of the first terminals P1+ and P1- and the second terminals P2+ and P2-. Alternatively, the BMS200 may sense that a drive unit is electrically connected to each of the first terminals P1+ and P1- and the second terminals P2+ and P2-. The BMS200 may be implemented in various ways to sense whether a drive device is connected to each terminal, and if necessary, a separate circuit may be provided to determine whether a drive device is connected to each terminal.

[0062] The BMS200 may decide to connect at least one of the first drive unit 21 and the second drive unit 22 to the battery system 1. If it decides to connect the first drive unit 21, the BMS200 may generate on-level relay control signals RCS11 and RCS12 and transmit them to relays 311 and 312. If it decides to connect the second drive unit 22, the BMS200 may generate on-level relay control signals RCS21 and RCS22 and transmit them to relays 321 and 322.

[0063] The BMS200 determines the voltages P100+ and P100- across the battery unit 100 according to which of the first drive unit 21 and second drive unit 22 is connected to the battery unit 100. If the determined voltages across the battery unit are the second voltage V2, the BMS200 determines which battery packs from among the multiple battery packs 101 to 104 will be connected in series, and whether or not to connect the battery packs connected in series in parallel. For the sake of explanation, the battery packs that the BMS200 has decided to connect in series in response to the second voltage V2 will be referred to as the series group.

[0064] Depending on the determined configuration of the series-connected battery packs, the BMS200 may generate on-level or off-level switching control signals SCS1_P~SCS4_P, SCS1_N~SCS4_N, SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4, and SCS3_4 to control the operation of multiple switching elements S1_P~S4_P, S1_N~S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4. For the sake of explanation, the operation in which the BMS200 controls the switching operation of multiple switching elements S1_P~S4_P, S1_N~S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 will be referred to as "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 drive unit 21 or the second drive unit 22 is a power converter connected to a charger, the BMS 200 may perform switching control operations so that the voltages across both ends P100+, P100- of the battery device 100 correspond to either the first voltage V1 or the second voltage V2, depending on which terminal among the first terminals P1+, P1- and the second terminals P2+, P2- to which the drive unit is connected.

[0068] When the first drive unit 21 or the second drive unit 22 is a load, the BMS 200 may perform switching control operations based on information received from the ECU 3 so that the voltages across the battery device 100, P100+ and P100-, correspond to either the first voltage V1 or the second voltage V2. For example, the user can select the discharge level of 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 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 to the BMS 200 indicating that the first voltage V1 has been selected.

[0069] If the first drive unit 21 is connected to the first terminals P1+ and P1-, and the battery unit 100 is performing a charging operation, or if the discharge level of the battery unit 100 selected by the user is the first voltage V1, the BMS 200 may perform a switching control operation so that the voltages at both ends P100+ and P100- of the battery unit 100 correspond to the first voltage V1. Alternatively, even if the discharge level of the battery unit 100 is not selected, the BMS 200 may perform a switching control operation so that the voltages at both ends P100+ and P100- of the battery unit 100 correspond to the first voltage V1.

[0070] If the second drive unit 22 is connected to the second terminals P2+ and P2-, and the battery device 100 is performing a charging operation, or if 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 voltages at both ends P100+ and P100- of the battery device 100 correspond to the second voltage V2.

[0071] The BMS200 may control the switching operation of multiple switching elements S1_P~S4_P, S1_N~S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 based on the respective pack voltages and / or pack capacities of multiple battery packs 101~104. Alternatively, the BMS200 may control the switching operation of multiple switching elements S1_P~S4_P, S1_N~S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 in response to commands input from the ECU3. For the sake of explanation, the BMS200 will be described below as controlling the switching operation of multiple switching elements S1_P~S4_P, S1_N~S4_N, S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 based on the respective pack voltages of multiple battery packs 101~104.

[0072] When multiple relays 311 and 312 are turned on and the first drive unit 21 is connected to the battery unit 100, the BMS 200 may determine the voltages at both ends P100+ and P100- of the battery unit 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 drive unit 21. Since the pack voltage of each of the multiple battery packs 101 to 104 corresponds to the voltage of the first voltage V1, the BMS 200 may determine at least one of the multiple battery packs 101 to 104 to be connected to both ends P100+ and P100- of the battery unit 100.

[0073] The following describes the switching control operation of the BMS200, which corresponds the terminals P100+ and P100- of the battery device 100 to the first voltage V1, with reference to Figure 2.

[0074] Figure 2 shows an example of the battery system shown in Figure 1.

[0075] The BMS200 may determine at least one battery pack from among the multiple battery packs 101 to 104 to be connected to the terminals P100+ and P100- of the battery device 100, based on the respective pack voltages of the multiple battery packs 101 to 104. The BMS200 may store a first reference voltage range, which is the normal range of voltages at the terminals P100+ and P100- of the battery device 100, corresponding to a first voltage. The BMS200 may determine at least one battery pack in which the voltages at the terminals P100+ and P100- of the battery device 100 are within the first reference voltage range.

[0076] The BMS200 may have one battery pack connected to both ends P100+ and P100- of the battery device 100, or two or more battery packs connected in parallel.

[0077] In the example shown in Figure 2, the BMS200 may connect battery pack 101, battery pack 103, and battery pack 104 from among the multiple battery packs 101 to 104 to both ends P100+ and P100- of the battery device 100.

[0078] Multiple series switching elements S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4 may be turned off, and among the multiple positive switching elements S1_P~S4_P and multiple negative switching elements S1_N~S4_N, the elements corresponding to the battery packs connected to both ends P100+ and P100- of the battery device 100 may be turned on. In the example in Figure 2, the BMS200 may 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, S4_P and three negative switching elements S1_N, S3_N, S4_N corresponding to battery packs 101, 103, and 104.

[0079] 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. Of the multiple switching control signals SCS1_P~SCS4_P, SCS1_N~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 off-level. For the sake of explanation, in the following, among the multiple switching control signals SCS1_P~SCS4_P, SCS1_N~SCS4_N, SCS1_2, SCS1_3, SCS1_4, SCS2_3, SCS2_4, and SCS3_4, all except those explicitly designated as on-level will be considered off-level.

[0080] In Figure 1, when multiple relays 321 and 322 are turned on and the second drive unit 22 is connected to the battery unit 100, the BMS 200 may determine the voltages at both ends P100+ and P100- of the battery unit 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 unit 22. Since the voltages at both ends of series groups of two battery packs 101 to 104 connected in series correspond to the voltages at both ends P100+ and P100- of the battery unit 100, the BMS 200 may determine at least one series group from the multiple battery packs 101 to 104 to connect to both ends P100+ and P100- of the battery unit 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] The following describes the switching control operation of the BMS200, which corresponds the terminals P100+ and P100- of the battery device 100 to the first voltage V1, with reference to Figure 3.

[0082] Figure 3 shows an example of a battery system that includes multiple series groups as shown in Figure 1.

[0083] The BMS200 may determine at least one series group from among the battery packs 101 to 104 to be connected to the terminals P100+ and P100- of the battery device 100, based on the respective pack voltages of the battery packs 101 to 104. The BMS200 may also store in advance a second reference voltage range, which is the normal range of voltages at the terminals P100+ and P100- of the battery device 100, corresponding to a second voltage. The BMS200 may determine at least one series group in which the voltages at the terminals P100+ and P100- of the battery device 100 are within the second reference voltage range.

[0084] The BMS200 may have one series group connected to both ends P100+ and P100- of the battery device 100, or two or more series groups connected in parallel.

[0085] In this specification, the number of battery packs belonging to a series group has been described as two, but the present invention is not limited thereto. The BMS200 may determine a number of battery packs as a series group that corresponds to the value obtained by dividing the second voltage V2 by the first voltage V1.

[0086] The BMS200 may turn on the switching element connected between two battery packs belonging to a series group from among the multiple series switching elements S1_2, S1_3, S1_4, S2_3, S2_4, and S3_4, and turn off the remaining switching elements. The BMS200 may turn on the switching element connected to the positive terminal P100+ of the battery device 100 from among the multiple positive switching elements S1_P to S4_P, and turn off the remaining switching elements. The BMS200 may turn on the switching element connected to the negative terminal P100 of the battery device 100 from among the multiple negative switching elements S1_N to S4_N, and turn off the remaining switching elements.

[0087] The BMS200 may determine which battery packs belong to each of at least one series group in order to perform switching control operations so that the voltages at both ends P100+ and P100- of the battery device 100 correspond to the second voltage V2.

[0088] The following explanation assumes 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 BMS200 may derive the voltage across each of at least one series group by considering the pack voltage of the battery packs belonging to each of at least one series group.

[0090] If there are two or more series groups, the BMS200 needs to determine which series group the potential 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 less than or equal to a predetermined threshold. For example, the predetermined threshold may be 20V.

[0091] When the voltage difference between two or more series groups is large, an inrush current may occur during operation if the battery device 100 is connected to the first drive unit 21 or the second drive unit 22. This is because an inrush current can cause shock to multiple battery packs 101-104 and components within the battery system 1.

[0092] Considering the respective pack voltages of multiple battery packs 101 to 104, the BMS200 may determine battery pack 101 and battery pack 104 as the first series group, and battery pack 102 and battery pack 103 as the second series group. The voltage across the first series group is V = 360 + 390 = 750 (V). The voltage across the second series group is V = 370 + 380 = 750 (V).

[0093] The BMS200 may connect a first series group, which includes battery pack 101 and battery pack 104, and a second series group, which includes battery pack 102 and battery pack 103, to both ends P100+ and P100- of the battery device 100, from among the multiple battery packs 101 to 104.

[0094] The BMS200 may generate an on-level switch control signal SCS1_4 and transmit it to the switching element S1_4 in order to connect battery packs 101 and 104 belonging to the first series group in series. The BMS200 may also generate an on-level switch control signal SCS2_3 and transmit it to the switching element S2_3 in order to connect battery packs 102 and 103 belonging to the second series group in series. 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 BMS200 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 them to the switching elements S1_P and S2_P. The BMS200 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 them to the switching elements S3_N and S4_N. 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 Figure 3, according to the 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+ and P100- of the battery device 100.

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

[0098] Figure 4 is a flowchart of a battery pack coupling control method according to one embodiment.

[0099] In the following sections, explanations of the BMS200's operation that overlap with the above explanation may be omitted.

[0100] The battery system 1 may be connected to the external system of the first drive unit 21 or the second drive unit 22 (S100). The BMS200 may connect the battery device 100 to the first drive unit 21 or the second drive unit 22 via a plurality of relays 311, 312, 321, and 322. The BMS200 may transmit on-level relay control signals RCS11 and RCS12 to relays 311 and 312 and connect the battery device 100 to the first drive unit 21 via terminals P1+ and P1-. Alternatively, the BMS200 may transmit on-level relay control signals RCS21 and RCS22 to relays 321 and 322 and connect the battery device 100 to the second drive unit 22 via terminals P2+ and P2-.

[0101] The BMS200 may determine whether the voltages across the battery device 100, P100+ and P100- are the first voltage V1 or the second voltage V2 (S200).

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

[0103] In step S200, if the voltages at both ends P100+ and P100- of the battery device 100 are the first voltage V1, the BMS200 may connect one or more battery packs from a plurality of battery packs 101 to 104 in parallel to both ends P100+ and P100- of the battery device 100 (S300). The BMS200 may determine at least one battery pack to connect to both ends P100+ and P100- of the battery device 100 based on the pack voltage of each of the plurality of battery packs 101 to 104.

[0104] Following step S300, the BMS200 may perform switching control operations on switches corresponding to at least one battery pack that it has decided to connect to both ends P100+ and P100- of the battery device 100 (S400). In the example in Figure 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 a plurality of switching elements S1_P, S3_P, S4_P, S1_N, S3_N, and S4_N.

[0105] In step S200, if the voltages across terminals P100+ and P100- of the battery device 100 are the second voltage V2, the BMS200 may determine at least one series group to connect across terminals P100+ and P100- of the battery device 100 (S500).

[0106] The BMS200 may determine which battery packs belong to each of at least one series group of the multiple battery packs 101 to 104 based on the pack voltage of each of the multiple battery packs 101 to 104. If there are two or more series groups, the BMS200 may determine which battery packs belong to each of the multiple series groups such that the voltage difference between the voltages across the two or more series groups is less than or equal to a predetermined threshold.

[0107] Following step S500, the BMS200 may perform switching control operations on switches corresponding to at least one series group that it has decided to connect to both ends P100+, P100- of the battery device 100 (S600). In the example in Figure 3, the BMS200 may generate on-level switching control signals SCS1_4, SCS2_3, SCS1_P, SCS2_P, SCS4_N, and SCS3_N and transmit them to a plurality of switching elements S1_4, S2_3, S1_P, S2_P, S3_N, and S4_N.

[0108] According to one embodiment, the BMS200 may adjust the voltages at both ends P100+ and P100- of the battery device 100 to a voltage level corresponding to a first voltage V1 or a voltage level corresponding to a second voltage V2. When two or more battery packs from a plurality of battery packs 101 to 104 are connected in series, the battery packs belonging to the plurality of series groups may be determined, and the voltage difference between the voltages at both ends of the plurality of series groups may be kept below a predetermined threshold.

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

Claims

1. Battery device including multiple battery packs; First and second terminals connected to both ends of the battery device; and Based on multiple voltage measurement signals received from the multiple battery packs, the BMS derives multiple pack voltages for the multiple battery packs, determines the voltage at both ends of the battery device as the first voltage or second voltage depending on which of the first and second terminals the drive device is connected to, determines whether to connect the multiple battery packs in parallel or in series based on the voltage at both ends of the battery device, and, if the multiple battery packs are connected in series, determines which of the multiple battery packs to be connected in series based on the multiple pack voltages. A battery system including a battery system.

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

3. When a first drive device driven at the voltage level of the first voltage is connected to the first terminal, or when information is received from the ECU indicating the discharge level of the battery device as the first voltage, The aforementioned BMS is The voltage at both ends of the battery device is determined as the first voltage, and the ends of at least one battery pack among the plurality of battery packs are connected to the ends of the battery device. The battery system according to claim 2.

4. When a second drive device driven at the voltage level of the second voltage is connected to the second terminal, or when information is received from the ECU indicating that the discharge level of the battery device is the second voltage, The aforementioned BMS is The voltage at both ends of the battery device is determined as the second voltage, at least one series group is determined from the plurality of battery packs, which includes two or more battery packs connected in series, and both ends of the at least one series group are connected to both ends of the battery device. The battery system according to claim 2.

5. The aforementioned BMS is If the number of the aforementioned at least one series group is two or more, The two or more series groups are determined such that the difference between the sum of the voltages of multiple first battery packs belonging to a first series group and the sum of the voltages of multiple second battery packs belonging to a second series group is less than or equal to a predetermined threshold. The battery system according to claim 4.

6. The aforementioned BMS is A switch control signal is generated which 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 according to claim 5.

7. The BMS connects a battery device, including multiple battery packs, to an external system via either of the first and second terminals connected to both ends of the battery device; The BMS determines the voltage across the battery device as a first voltage or a second voltage depending on which of the first and second terminals the drive device is connected to; The BMS 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; A step of determining whether to connect the plurality of battery packs in parallel or in series based on the voltage across both ends of the battery device; and When connecting the multiple battery packs in series, the step of determining which of the multiple battery packs to connect in series is based on the voltage of the multiple battery packs. A method for controlling the coupling between battery packs, including the connection between them.

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

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

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

11. If the number of the aforementioned at least one series group is two or more, The step of determining the at least one series group is: The method further includes the step of determining two or more series groups such that the difference between the sum of multiple first pack voltages for multiple first battery packs belonging to a first series group and the sum of multiple second pack voltages for multiple second battery packs belonging to a second series group of the two or more series groups is less than or equal to a predetermined threshold. The method for controlling the coupling between battery packs according to claim 10.

12. The aforementioned BMS is The further step 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 method for controlling the connection between battery packs according to claim 11.

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