Battery management system and battery pack

Abstract

The present application relates to a battery management system and a battery pack, and the battery management system according to the embodiment of the present application comprises: a group voltage sampling unit configured to periodically sample a group voltage of the battery pack; a group current sampling unit configured to sample a group current of the battery pack; and a control unit configured to: after starting to sample the group voltage of the battery pack, when the sampling of the group voltage of the battery pack is completed, record a time from a sampling start time of the group voltage to a sampling completion time of the group voltage as a first time, and send a voltage sampling synchronization signal for measuring a single cell voltage of a battery cell to a plurality of subordinate battery management systems, wherein the control unit performs sampling synchronization on a sampling measurement signal between each subordinate battery management system based on a second time and the first time, the second time being a sampling time of performing single cell voltage measurement received from each subordinate battery management system.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2019-0097000, filed with the Korean Intellectual Property Office on August 8, 2019, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0004] This invention relates to battery management systems and battery packs. Background Technology

[0005] In order to accurately estimate the remaining capacity, lifespan, and available power of a battery, in addition to accurately measuring the voltage and current of individual battery cells, module cells, and battery pack cells, the corresponding voltage and current measurement points must be consistent.

[0006] However, in a wireless communication-based system architecture, for example, in which multiple battery management systems (hereinafter referred to as "BMS") are set up—for example, such as a lower-level battery management system (e.g., a module BMS) and a higher-level battery management system (e.g., a group BMS)—the synchronization signals used for voltage or current measurement cannot be received jointly from a higher-level controller (e.g., a main BMS) outside the battery pack. When each BMS measures the individual cell voltage, group voltage, etc., the measurement time points are inconsistent, resulting in the inability to accurately estimate the remaining capacity, lifespan, and available output of the battery. Summary of the Invention

[0007] [Technical Issues]

[0008] The present invention was made to solve the above-mentioned problems and provides a battery management system and battery pack that can match the measurement time points of voltage and current in the battery without the control signal from the main controller outside the battery.

[0009] [Technical Solutions]

[0010] A battery management system according to an embodiment of the present invention includes: a group voltage sampling unit configured to periodically sample the group voltage of a battery group; a group current sampling unit configured to sample the group current of the battery group; and a control unit configured to, after starting to sample the group voltage of the battery group, record a time from the start time of group voltage sampling to the completion time of group voltage sampling as a first time when the group voltage sampling of the battery group is completed, and send a sampling synchronization signal for measuring the individual cell voltage of a battery cell to a plurality of lower-level battery management systems. At this time, the control unit performs sampling synchronization on the sampling measurement signals between each lower-level battery management system based on a second time and the first time, wherein the second time is the sampling time for performing the individual cell voltage measurement received from each lower-level battery management system.

[0011] The battery management system according to an embodiment of the present invention may further include a communication unit, which includes a transmitting unit and a receiving unit. The transmitting unit is used to wirelessly broadcast a sampling synchronization signal to a plurality of lower-level battery management systems, and the receiving unit is used to wirelessly receive single-cell voltage sampling information at a second time and a second time from each lower-level battery management system.

[0012] For example, after the group voltage sampling is completed, and after the transmitting unit sends a sampling synchronization signal to multiple lower-level battery management systems, the group current sampling unit can perform group current sampling.

[0013] The second time can be the difference between the time when the lower-level battery management system starts measuring the individual cell voltage in the lower-level battery management system after receiving the sampling synchronization signal and the time when the individual cell voltage measurement ends.

[0014] In addition, the control unit can delay the sampling start time of the group voltage by half of the second time and position the generation time of the sampling synchronization signal in the middle of the second time, so that the control unit can perform sampling synchronization by synchronizing the measurement time of the individual cell voltage sampling information received from multiple lower-level battery management systems and the sampling information of the group voltage sampling unit.

[0015] For example, the control unit can send the individual cell voltage sampling information used to perform sampling synchronization to the upper-level controller.

[0016] Furthermore, according to another embodiment of the present invention, a battery management system includes: a receiving unit configured to receive a sampling synchronization signal for measuring the cell voltage of a battery cell from a higher-level battery management system; a cell voltage sampling unit configured to sample the cell voltage of a battery cell when the sampling synchronization signal is received; a control unit configured to calculate a second time, the second time being from the start time of cell voltage sampling to the completion time of cell voltage sampling; and a transmitting unit configured to transmit the calculated second time and the cell voltage sampling information during the second time period to the higher-level battery management system.

[0017] Furthermore, according to another embodiment of the present invention, a battery pack includes a plurality of lower-level battery management systems and at least one upper-level battery management system, wherein the upper-level battery management system includes: a group voltage sampling unit configured to periodically sample the group voltage of the battery pack; a group current sampling unit configured to sample the group current of the battery pack; and a first control unit configured to, after starting to sample the group voltage of the battery pack, record the time from the start time of group voltage sampling to the completion time of group voltage sampling as a first time when the group voltage sampling of the battery pack is completed, and send a sampling synchronization signal for measuring the individual cell voltage of the battery cells to the plurality of lower-level battery management systems, wherein each lower-level battery management system... The first-level battery management system includes: a single-cell voltage sampling unit configured to sample the single-cell voltage of a battery cell when a sampling synchronization signal for measuring the single-cell voltage of a battery cell is received from the upper-level battery management system; and a second control unit configured to calculate a second time from the start time of single-cell voltage sampling to the end time of single-cell voltage sampling, and to send the calculated second time and single-cell voltage sampling information during the second time to the upper-level battery management system, wherein the first control unit performs sampling synchronization on the sampled measurement signals between each lower-level battery management system based on the second time received from each lower-level battery management system and a first time.

[0018] For example, wireless communication is performed between the upper-level battery management system and each lower-level battery management system.

[0019] The control unit can delay the sampling start time of the group voltage by half of the second time and position the generation time of the sampling synchronization signal in the middle of the second time, so that the control unit can perform sampling synchronization by synchronizing the measurement time of the individual cell voltage sampling information received from multiple lower-level battery management systems and the sampling information of the group voltage sampling unit.

[0020] The group current sampling unit can perform group current sampling after the group voltage sampling is completed, and the sampling synchronization signal is sent to multiple lower-level battery management systems.

[0021] In addition, the first control unit can send the individual cell voltage sampling information used to perform sampling synchronization to the upper-level controller.

[0022] [Effects of the Invention]

[0023] According to the present invention, measurement time points such as voltage and current in the battery can be matched without control signals from a main controller outside the battery, thereby enabling a more accurate estimation of the battery's remaining capacity, lifespan, and available output.

[0024] Other effects of the invention will be further described according to the following embodiments. Attached Figure Description

[0025] Figure 1 It is a block diagram schematically illustrating the configuration of a typical battery pack.

[0026] Figure 2 This is a block diagram schematically illustrating the configuration of a wireless communication-based battery pack according to an embodiment of the present invention.

[0027] Figure 3 It is shown schematically. Figure 2 A block diagram of the configuration of the group BMS.

[0028] Figure 4 It is shown schematically. Figure 2 A block diagram of the BMS module configuration.

[0029] Figure 5 is a timing diagram used to explain the process of synchronizing the measurement signal. Figure 5(a) is the timing diagram before synchronization, and Figure 5(b) is the timing diagram after synchronization.

[0030] Figure 6 This is a flowchart illustrating the measurement synchronization method of the battery management system.

[0031] Figure 7 This is a block diagram illustrating the hardware configuration of a battery management system (BMS) according to an embodiment of the present invention. Detailed Implementation

[0032] In the following description, various embodiments of the invention will be described with reference to the accompanying drawings. However, this is not intended to limit the invention to the specific embodiments, but should be understood to include various modifications, equivalents, and / or substitutions of the embodiments of the invention. In the description of the drawings, the same reference numerals may be used for the same elements.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of other embodiments. Unless otherwise stated, singular terms may include plural forms. All terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art. Terms defined in common dictionaries may be interpreted as having the same or similar meaning as in the context of the prior art and are not to be construed as having an ideal or overly formal meaning unless expressly defined herein. In some cases, even terms defined in this document should not be construed as excluding embodiments of the invention.

[0034] Furthermore, when describing the constituent elements of embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are used only to distinguish components from other components, and the nature, order, or sequence of components is not limited by these terms. If a component is described as being "connected," "coupled," or "joined" to another component, then that component may be directly connected to or connected to another component; however, it should be understood that another component may be "connected," "coupled," or "joined" between each component.

[0035] Reference Figure 1 This will describe the basic configuration of the battery pack. Figure 1 It is a block diagram schematically illustrating the configuration of a typical battery pack.

[0036] like Figure 1 As shown, battery pack B includes: at least one battery module 1, which is composed of one or more battery cells and is capable of charging and discharging; a switching unit 2, which is connected in series to the + terminal side or - terminal side of battery module 1 to control the charging / discharging current flow of battery module 1; and a battery management system 3, which is used to control and manage the voltage, current, temperature, etc. of battery pack B to prevent overcharging and over-discharging.

[0037] Here, the switching unit 2 is a mechanical switching element or a semiconductor switching element used to control the current flow for charging or discharging the battery module 1, and for example, at least one mechanical relay or MOSFET can be used.

[0038] Furthermore, to monitor the voltage, current, temperature, etc. of battery pack B, BMS 3 is connected to battery module 1 and can receive data regarding voltage, current, temperature, etc. Additionally, for example, when switching unit 2 is a semiconductor switching element, the voltage and current of the gate, source, and drain of the semiconductor switching device can be measured or calculated. Furthermore, the current, voltage, temperature, etc., of battery module 1 can also be measured using various sensors 4 disposed adjacent to the semiconductor switching element. The data such as current, voltage, and temperature obtained as described above can be used to estimate the remaining capacity, lifespan, and available output of the battery. BMS 3 is an interface for receiving values ​​obtained by measuring the various parameters mentioned above and may include multiple terminals and circuitry connected to these terminals to process the input values.

[0039] In addition, BMS 3 can control the switching unit 2 to turn on / off, and can be connected to battery module 1 to monitor the status of battery module 1.

[0040] Depending on the application, Figure 1 Battery pack B is configured as a unit of a battery module, and multiple battery packs B can be connected in series or parallel to form a battery pack (or battery rack). In this case, although not shown in the figure, for example, the battery pack includes multiple lower-level battery management systems (e.g., module BMS) disposed in each battery module unit, and at least one upper-level battery management system (e.g., group BMS) for managing the multiple lower-level battery management systems.

[0041] Here, the lower-level battery management system set in each battery module unit can control the charging and discharging of the corresponding battery module by measuring the individual cell voltage or module voltage in the corresponding battery module. In addition, it can send the measured individual cell voltage or module voltage to the upper-level battery management system, and can also receive the control commands required for charging and discharging from the upper-level battery management system.

[0042] Similarly, a higher-level battery management system used to manage multiple lower-level battery management systems can measure the total group voltage or group current of the multiple battery modules connected in series and parallel. In addition, it can receive the individual cell voltage or module voltage from each lower-level battery management system, control the charging and discharging of the battery pack, and send the control commands required for charging and discharging to each lower-level battery management system.

[0043] In this scenario, data can be sent and received between battery management systems via wireless communication. This requires synchronizing measurement signals from the lower-level battery management system and the upper-level battery management system.

[0044] Next, we will refer to Figures 2 to 4A method for synchronizing measurement signals between battery management systems is described according to an embodiment of the present invention. Figure 2 This is a block diagram schematically illustrating the configuration of a wireless communication-based battery pack according to an embodiment of the present invention. Figure 3 It is shown schematically. Figure 2 A block diagram of the BMS configuration, and Figure 4 It is shown schematically. Figure 2 A block diagram of the BMS module configuration.

[0045] like Figure 2 As shown, the battery pack 100 according to an embodiment of the present invention includes at least one group BMS 10 and a plurality of module BMS 20.

[0046] First, as the upper-level battery management system, the group BMS10 may include a group voltage sampling unit 11, a group current sampling unit 13, and a first control unit 15, such as... Figure 3 As shown.

[0047] The battery pack voltage sampling unit 11 periodically samples the battery pack voltage. For example, it periodically samples the battery pack voltage signal measured from the terminals used to measure the battery pack voltage.

[0048] The pack current sampling unit 13 samples the pack current of the battery pack. For example, the pack current signal measured from a sensor used to measure the pack current is sampled. For example, the pack current sampling unit 13 can perform pack current sampling after the pack voltage sampling is completed and the sampling synchronization signal is sent to the multiple module BMS 20.

[0049] After the sampling of the battery pack voltage begins, when the sampling of the battery pack voltage is completed, the first control unit 15 records the time from the start time of the sampling of the battery pack voltage to the completion time of the sampling of the battery pack voltage as the first time, and controls the sampling synchronization signal for measuring the individual cell voltage of the battery cells to be sent to multiple modules BMS20.

[0050] In addition, the group BMS10 may also include a first communication unit 17 for communicating with multiple module BMS 20.

[0051] The first communication unit 17 may include, for example, a transmitting unit 17A for wirelessly broadcasting sampling synchronization signals to multiple module BMS20s, and a receiving unit 17B for wirelessly receiving data signals from each module BMS20. For example, the receiving unit 17B may receive second time and measurement signal data from each module BMS20, where the second time is the sampling time for performing individual cell voltage measurements, and the measurement signal data is individual cell voltage sampling information during the second time period. For example, the second time may be the difference between the time when module BMS20 begins measuring the individual cell voltage in module BMS20 after receiving the sampling synchronization signal and the time when the individual cell voltage measurement is completed.

[0052] In addition, the BMS10 may also include a memory (not shown) for recording first time, second time, and measurement signal data.

[0053] Meanwhile, each module BMS20 is a lower-level battery management system and may include a single-cell voltage sampling unit 21 and a second control unit 25, such as... Figure 4 As shown.

[0054] When a sampling synchronization signal for measuring the individual cell voltage is received from the group BMS10, the individual cell voltage sampling unit 21 samples the individual cell voltage. Furthermore, when a sampling synchronization signal for measuring the individual cell voltage is received from the group BMS10, the individual cell voltage sampling unit 21 can further sample the module voltage of the battery module in which the corresponding individual cells are connected in series and / or parallel.

[0055] The second control unit 25 calculates a second time for a measurement signal such as the unit voltage, the second time being the time from the start of sampling to the completion of sampling, and controls the transmission of the calculated second time and the measurement sampling information used for the second time to the group BMS 10.

[0056] In addition, each module BMS20 may also include a second communication unit 27 for communicating with group BMS 10.

[0057] The second communication unit 27 may include, for example, a receiving unit 27B and a transmitting unit 27A. The receiving unit 27B is used to wirelessly receive from the group BMS10 a sampling synchronization signal for measuring the cell voltage of a battery cell. The transmitting unit 27A is used to wirelessly transmit measurement signal data, such as sampling information of the cell voltage for a second time, and the second time to the group BMS10. Therefore, signals can be transmitted and received via wireless communication between the group BMS10 and the module BMS20 or between different modules BMS20.

[0058] Additionally, module BMS20 may include a memory (not shown) for recording second time and measurement signal data.

[0059] Here, the first control unit 15 of the group BMS10 synchronizes measurement signals such as group voltage measured by the group BMS10 and individual voltage measurement signals such as those measured by the module BMS20. Specifically, sampling synchronization is performed on the measurement signals sampled between each module BMS20 based on a second time, which is the sampling time for performing individual voltage measurements received from each module BMS20, and a first time related to group voltage sampling. For example, when the group voltage sampling start time is delayed by half of the second time, and the sampling synchronization signal is generated in the middle of the second time, the first control unit 15 can synchronize the measurement times of individual voltage sampling information received from multiple module BMS20s and the sampling information of the group voltage sampling unit 11 to perform sampling synchronization.

[0060] The process of synchronizing the measurement signal will be described in detail with reference to Figure 5. Figure 5 is a timing diagram used to explain the process of synchronizing the measurement signal. Figure 5(a) is the timing diagram before synchronization, and Figure 5(b) is the timing diagram after synchronization.

[0061] As shown in Figure 5(a), before synchronization is performed, the group voltage sampling unit 11 of the group BMS10 first periodically samples the group voltage V during Δp (i.e., the group voltage measurement time, the first time). PACK Immediately after the group voltage sampling is completed, the first control unit 15 generates a sampling synchronization signal MSR Trig and sends the sampling synchronization signal MSR Trig to module BMS20. Furthermore, the group current sampling unit 13 samples the group current I during Δc (i.e., the group current measurement time). PACK Sampling is performed. On the other hand, based on the received sampling synchronization signal MSR Trig., the individual voltage sampling unit 21 of module BMS20 performs sampling for each pair of individual voltages V from individual 1 to 96 during the Δs period. CELL Sequential sampling. However, Figure 5(a) shows sequential sampling of individual units for a duration of Δs in units of 6, but it is not limited to this. Additionally, based on the received sampling synchronization signal MSR Trig., the individual unit voltage sampling unit 21 can further sample the module voltage V. MODULE The sampling duration is a predetermined time (e.g., Δs / 2). Here, the group voltage V PACK and group current I PACK The data is from BMS10 group, and the individual cell voltage V CELL and module voltage V MODULEThe data is measured from module BMS20. Furthermore, group BMS10 can measure and record Δp and Δc based on an internal clock signal generated, for example, by a clock generator (not shown) located therein; similarly, module BMS20 can measure and record Δs based on an internal clock signal generated, for example, by a clock generator (not shown) located therein. Here, Δh represents the cycle time used to send the individual cell voltage measurement signal from module BMS20 to group BMS10.

[0062] At the same time, the first control unit 15 can control the group voltage V PACK Group current I PACK Individual voltage V CELL and module voltage V MODULE The sampling measurement signal is synchronized. For example, as shown in Figure 5(b), since the sampling start time of the group voltage is delayed by 1 / 2 of the second time (i.e., delayed by Δs / 2) and the generation time of the sampling synchronization signal MSR Trig. is in the middle of the second time, the sampling information V received from each module BMS20 can be synchronized. CELL and V MODULE The measurement time and the sampling information V measured by the BMS10 group itself. PACK and I PACK To perform synchronization, we need to perform sampling synchronization.

[0063] In this way, according to the present invention, measurement time points such as voltage and current in the battery can be matched without control signals from a main controller outside the battery, thereby enabling a more accurate estimation of the battery's remaining capacity, lifespan, and available output.

[0064] Furthermore, the first control unit 10 of the group BMS 10 can send sampling result information obtained by performing sampling synchronization to the upper-level controller 200. For example, individual cell voltage sampling information can be sent to the upper-level controller 200. Additionally, the first control unit 10 of the group BMS 10 can send information about the battery status and control to the upper-level controller 200, or control the operation of the battery pack 100 based on control signals applied from the upper-level controller 200. The first control unit 10 of the group BMS 10 can exchange various signals and data with the upper-level controller 200 via wired and / or wireless means. Here, the battery pack 100 can be, for example, a battery pack of an energy storage system (ESS), and the upper-level controller 200 can be, for example, a main BMS that integrates and manages multiple battery packs 100. However, the invention is not limited thereto; the battery pack 100 can be an automotive battery pack, and the upper-level controller 200 can be a microcontroller (MCU) of an automotive system.

[0065] Furthermore, this invention can be implemented as a higher-level battery management system, such as a group BMS 10, applied in a battery pack 100, and can also be implemented as a lower-level battery management system, such as a module BMS 20. However, since the higher-level and lower-level battery management systems are the same as described above, detailed descriptions will be omitted.

[0066] Next, we will refer to Figure 6 Describe the measurement synchronization method of group BMS10. Figure 6 This is a flowchart illustrating the measurement synchronization method of the battery management system.

[0067] First, when group BMS10 starts measuring, group voltage sampling unit 11 starts sampling the group voltage (S10). Next, it is determined whether the sampling of the group voltage has been completed under predetermined conditions (S11). For example, the predetermined conditions may be a predetermined time or a predetermined number of samplings. If it is determined that the sampling of the group voltage has not been completed (No), the internal clock CLK1++ is added to Δp (i.e., the group voltage measurement time, the first time) (S13), and the process returns to operation S11. If, in operation S11, it is determined that the sampling of the group voltage has been completed (Yes), the first control unit 15 extracts Δp, uses Δp to generate a sampling synchronization signal MSRTrig, and sends this signal to module BMS20 (S20). First, when group BMS13 starts measuring, group voltage sampling unit 11 starts sampling the group voltage (S10). Next, it is determined whether the sampling of the group current has been completed under predetermined conditions (S31). For example, the predetermined conditions may be a predetermined time or a predetermined number of samplings. If it is determined that the sampling of the group current has not yet been completed (No), the internal clock CLK1++ is added to Δc (i.e., the group current measurement time) (S33), and the process returns to operation S31. If, in operation S31, it is determined that the sampling of the group current has been completed (Yes), the first control unit 15 extracts Δc (S35).

[0068] On the other hand, after step S20, when the sampling synchronization signal MSR Trig. is received, the individual voltage sampling unit 21 of module BMS20 begins sampling the individual voltage and / or module voltage (S40). For example, the module voltage sampling time can be 1 / 2 of the individual voltage sampling time. Next, it is determined whether the individual voltage sampling has been completed under predetermined conditions (S41). For example, the predetermined conditions can be a predetermined time or a predetermined number of samplings. If it is determined that the individual voltage sampling has not been completed (No), the internal clock CLK2++ is added to Δs (i.e., the individual voltage measurement time in module BMS20, the second time) (S43), and the process returns to operation S41. If, in operation S41, it is determined that the individual voltage sampling is completed (Yes), Δs is extracted (S45). Subsequently, module BMS20 sends the Δs / 2 value to group BMS10 (S50). Subsequently, the first control unit 15 of group BMS 10 delays the measurement time of group voltage and group current by Δs / 2 based on the received Δs / 2 value, performs sampling synchronization between the sampled signal measured in group BMS 10 and the sampled signal measured in module BMS 20, and returns to operation S10 again, so that the measurement synchronization process can be repeated periodically. Here, module BMS 20 sends the Δs / 2 value to group BMS 10, but module BMS 20 can send the Δs value, and group BMS 10 can delay the Δs / 2 value.

[0069] Meanwhile, the lower-level or upper-level battery management system of the battery pack 100 of the present invention can be expressed in hardware, such as... Figure 7 As shown. Figure 7 This is a block diagram illustrating the hardware configuration of a battery management system 300 according to an embodiment of the present invention.

[0070] like Figure 7 As shown, the battery management system 300 may include a microcontroller (MCU) 310 for controlling various processes and configurations, a memory 320 containing operating system programs and various programs (e.g., sampling synchronization programs, battery pack anomaly diagnosis programs, or battery pack temperature estimation programs), an input / output interface 330 providing input and output interfaces between battery modules and / or switching units (e.g., semiconductor switching devices), and a communication interface 340 capable of communicating with external entities (e.g., a higher-level controller) via wired or wireless communication networks. In this way, the computer program according to the invention can be recorded in the memory 320 and processed by the microcontroller 310, and can be implemented, for example, to execute... Figures 2 to 4 The modules of each functional block shown.

[0071] In this way, according to the present invention, measurement time points such as voltage and current in the battery can be matched without control signals from a main controller outside the battery, thereby enabling a more accurate estimation of the battery's remaining capacity, lifespan, and available output.

[0072] In the foregoing, although the invention has been described with reference to limited embodiments and accompanying drawings, the invention is not limited thereto, and it will be apparent to those skilled in the art that various embodiments are possible within the scope of the technical concept of the invention and the equivalents of the claims described below.

Claims

1. A battery management system comprising: a pack voltage sampling unit configured to periodically sample a pack voltage of a battery pack; a pack current sampling unit configured to sample a pack current of the battery pack; and a control unit configured to, after starting sampling of the pack voltage of the battery pack, record a time from a sampling start time of the pack voltage to a sampling completion time of the pack voltage as a first time when the pack voltage sampling of the battery pack is completed, and transmit a sampling synchronization signal for measuring a cell voltage of a battery cell to a plurality of subordinate battery management systems, wherein the control unit performs sampling synchronization of a sampling measurement signal between each of the subordinate battery management systems based on a second time and the first time, the second time being a sampling time of performing a cell voltage measurement received from each of the subordinate battery management systems, wherein the second time is a difference between a time when a subordinate battery management system starts measuring a cell voltage in the subordinate battery management system after receiving the sampling synchronization signal and a time when the cell voltage measurement ends. 2.The battery management system of claim 1, further comprising a communication unit including a transmission unit for wirelessly broadcasting the sampling synchronization signal to the plurality of subordinate battery management systems and a reception unit for wirelessly receiving the second time and cell voltage sampling information of the second time from each of the subordinate battery management systems. the pack current sampling unit performs pack current sampling after the pack voltage sampling is completed, after the transmission unit transmits the measurement synchronization sampling synchronization signal to the plurality of subordinate battery management systems.

3. The battery management system of claim 2, wherein, the control unit delays a sampling start point of the pack voltage by 1 / 2 of the second time and positions a generation point of the sampling synchronization signal in the middle of the second time, so that the control unit performs the sampling synchronization by synchronizing a measurement time of cell voltage sampling information received from the plurality of subordinate battery management systems and sampling information of the pack voltage sampling unit.

4. The battery management system of claim 1, wherein, the control unit transmits the cell voltage sampling information for performing the sampling synchronization to a superior controller.

5. The battery management system of claim 4, wherein, 6.A battery pack comprising a plurality of subordinate battery management systems and at least one superior battery management system, the superior battery management system comprising: wherein a pack voltage sampling unit configured to periodically sample a pack voltage of a battery pack; a pack current sampling unit configured to sample a pack current of the battery pack; and a first control unit configured to, after starting sampling of the pack voltage of the battery pack, record a time from a sampling start time of the pack voltage to a sampling completion time of the pack voltage as a first time when the pack voltage sampling of the battery pack is completed, and transmit a sampling synchronization signal for measuring a cell voltage of a battery cell to the plurality of subordinate battery management systems, ​ wherein each lower-level battery management system includes: a cell voltage sampling unit configured to sample a cell voltage of a battery cell when receiving a sampling synchronization signal for measuring the cell voltage of the battery cell from the upper-level battery management system; and a second control unit configured to calculate a second time, which is a time from a time point at which cell voltage sampling is started to a time point at which cell voltage sampling is completed, and transmit the calculated second time and cell voltage sampling information during the second time to the upper-level battery management system, wherein the first control unit performs sampling synchronization of the sampled measurement signals between each lower-level battery management system based on the second time and the first time received from each lower-level battery management system.

7. The battery pack of claim 6, wherein, wireless communication is performed between the upper-level battery management system and each lower-level battery management system.

8. The battery pack of claim 6, wherein, The first control unit delays a sampling start time point of the group voltage by 1 / 2 of the second time, and positions a generation time point of the sampling synchronization signal at the middle of the second time, so that the first control unit performs the sampling synchronization by synchronizing measurement times of cell voltage sampling information received from the plurality of lower-level battery management systems and sampling information of the group voltage sampling unit.

9. The battery pack of claim 6, wherein, The group current sampling unit performs group current sampling after the group voltage sampling is completed and the sampling synchronization signal is transmitted to the plurality of lower-level battery management systems.

10. The battery pack of claim 6, wherein, The first control unit transmits the cell voltage sampling information for performing the sampling synchronization to an upper-level controller.

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