A diagnostic system and method for battery cells that support one-to-many wireless communication using a common frequency channel and multiple communication frequency channels.

Abstract

The present invention relates to a battery cell diagnostic system and method for supporting one-to-many wireless communication using a common frequency channel and multiple communication frequency channels, and includes a master BMS and multiple direct BMSs. The battery cell connection section included in each direct BMS directly contacts the positive and negative terminals of multiple battery cells included in a battery module, and can measure raw voltage data of the battery cells and raw current data of the battery module. Each direct BMS can transmit information of the contacted battery module to the master BMS using an asynchronous wireless communication method. By efficiently allocating the common frequency channel and multiple communication frequency channels to the 900 MHz band, which is an unlicensed communication band, the system does not include configurations related to intermediate communication stations adopted in conventional battery management systems including slave BMSs or module BMSs, and can stably operate one-to-many wireless communication between multiple direct BMSs and a single master BMS.

Description

Technical Field

[0001] The present invention relates to a battery cell diagnosis system and method for supporting one-to-many wireless communication using a common frequency channel and a plurality of communication frequency channels. More specifically, it includes a master BMS and a plurality of direct BMSs. The battery cell connection parts included in each direct BMS directly contact the respective positive and negative terminals of the plurality of battery cells included in the battery module, and can measure the load data of the voltage of each corresponding battery cell and the load data of the current of the battery module. Each of the plurality of direct BMSs can transmit the information of the battery module it contacts to the master BMS in an asynchronous wireless communication method. By efficiently allocating a common frequency channel and a plurality of communication frequency channels in the 900 MHz band, which is an unlicensed communication band, it does not include the configuration related to the communication location that would be involved in the conventional battery management system including a slave BMS or a module BMS, and can stably operate one-to-many wireless communication between the plurality of direct BMSs and a single master BMS. The present invention relates to a battery cell diagnosis system and method for supporting one-to-many wireless communication using a common frequency channel and a plurality of communication frequency channels.

Background Art

[0002] In recent years, environmental regulations on internal combustion engine vehicles have become stricter worldwide. As a result, the demand for vehicles that use the power of a battery (electric cell), such as electric vehicles (EVs) or hybrid vehicles (MHEVs, PHEVs, FHEVs), has been increasing. Consequently, the interest of automotive companies worldwide in battery management technology to improve the efficiency, performance, durability, etc. of batteries has been growing, and many manufacturers and research groups are actively conducting research and development in this regard.

[0003] <00,00013>On the other hand, electric vehicles have longer charging times and shorter driving ranges compared to conventional internal combustion engine vehicles. Therefore, automakers are showing a tendency to equip electric vehicles with large-capacity batteries to ensure the longest possible driving range. However, large-capacity batteries contain thousands of battery cells, and as the number of battery cells installed in a vehicle increases, the importance of a Battery Management System (BMS) to manage and control large-capacity batteries is becoming increasingly apparent.

[0004] Conventional battery management systems, such as the one published in the Republic of Korea Patent No. 10-2015-0048439, have a structure in which a predetermined number of battery cells are modularized into battery modules, each battery module is connected to a slave BMS, the status of the corresponding module is grasped, and this is transmitted to the master BMS. On the other hand, as mentioned above, as the number of battery cells increases, the number of cables connecting each battery cell to a slave BMS and connecting the slave BMS to the master BMS also increases, and the problems caused by this increase are progressively greater.

[0005] On the other hand, while prior art such as the Republic of Korea Published Patent No. 10-2023-0004400, which wirelessly connects multiple slave BMSs and master BMSs, has been published, it still employs a wired connection method using electrical and communication cables between the battery and the BMS. It does not disclose or suggest a wireless communication system that takes into account the unique characteristics of vehicles, nor does it mention a configuration that enables stable communication, reduces costs, and improves space utilization. Therefore, there is a need for a new type of BMS technology that improves upon the aforementioned problems of conventional BMS technology. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Republic of Korea Published Patent No. 10-2015-0048438 (2015.05.07) [Patent Document 2] Republic of Korea Published Patent No. 10-2023-0004400 (2023.01.06) [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention provides a battery cell diagnostic system and method for supporting one-to-many wireless communication using a common frequency channel and multiple communication frequency channels, more specifically comprising a master BMS and multiple direct BMSs, wherein the battery cell connection portion included in each direct BMS directly contacts the positive and negative terminals of each of the multiple battery cells included in a battery module, and can measure the raw voltage data of each of the battery cells and the raw current data of the battery module, and each of the multiple direct BMSs can transmit information of the battery module it has contacted to the master BMS using an asynchronous wireless communication method, and by efficiently allocating the common frequency channel and multiple communication frequency channels to the 900 MHz band, which is an unlicensed communication band, the present invention aims to provide a battery cell diagnostic system and method for supporting one-to-many wireless communication using a common frequency channel and multiple communication frequency channels, without including configurations related to intermediate communication stations adopted in conventional battery management systems including slave BMS or module BMS, and enabling stable operation of one-to-many wireless communication between multiple direct BMSs and a single master BMS. [Means for solving the problem]

[0008] To solve the aforementioned problems, one aspect of the present invention is a diagnostic system for battery cells located in a vehicle, comprising: a plurality of direct BMSs located in the vehicle and electrically connected to a plurality of battery cells included in a battery module; and a master BMS located in the vehicle and performing wireless communication with the direct BMS, wherein the direct BMS includes a battery cell connection section having ports that directly physically and electrically contact the exposed electrodes of each of the plurality of battery cells; a voltage measuring section electrically connected to the battery cell connection section and measuring the voltage of each battery cell in a circuit configuration; and a current measuring section electrically connected to the battery cell connection section and measuring the current of a battery cell or battery module in a circuit configuration. The system includes a setting unit, an MCU, and a first wireless communication unit connected to the MCU and performing wireless communication with the master BMS, wherein the master BMS sets a communication frequency channel for each of the direct BMSs located in the vehicle, broadcasts broadcast data containing channel information relating to the communication frequency channel for each direct BMS at a predetermined interval on a common frequency channel, and the direct BMSs are configured to receive the data transmitted on the common frequency channel, and provide a battery cell diagnostic system that transmits and receives information about the battery cell with the master BMS on its own communication frequency channel included in the broadcast data received on the common frequency channel.

[0009] The positive and negative terminals of the battery cell are in direct contact with the ports provided in the battery cell connection section, and the voltage measuring unit measures the voltage for each of the battery cells.

[0010] The aforementioned communication frequency channel corresponds to a channel through which data is transmitted and received wirelessly between a plurality of direct BMSs and the master BMS, and includes a plurality of communication frames, each of which includes a subframe comprising a downlink frame broadcast by the master BMS to the plurality of direct BMSs and a plurality of uplink frames transmitted by each of the plurality of direct BMSs to the master BMS, with each uplink frame in the subframe being temporally divided.

[0011] The data received by multiple direct BMSs via the downlink frame on the communication frequency channel includes identifier information for each direct BMS and time-division information of the uplink frame relating to the direct BMS having the identifier information. Each direct BMS transmits data for the battery cells connected to it to the master BMS via the uplink frame assigned to it, based on the time-division information and channel information of its own uplink frame included in the data received in the downlink frame.

[0012] Each of the aforementioned communication frequency channels and common frequency channels falls within the 900MHz band, and the types of data transmitted and received through each channel are different.

[0013] The aforementioned communication frequency channel includes multiple narrowband channels divided at 200 kHz intervals within a 900 MHz bandwidth.

[0014] The communication frame of the aforementioned communication frequency channel includes multiple identical subframes, and each subframe is configured according to a predetermined rule, with multiple uplink frames following the downlink frame in time. The data broadcast in the downlink frame includes request information for the target to be transmitted from each direct BMS. Each direct BMS generates response information in response to the request information contained in the data broadcast in the downlink frame and transmits the data including the response information to the master BMS using the time-division multiplexing information and channel information of its own uplink frame.

[0015] If a master BMS detects a communication error during communication with multiple direct BMSs, the master BMS modifies the time-division information of the direct BMS corresponding to the uplink frame where the communication error occurred, and then broadcasts the data including the modified time-division information through the communication frequency channel.

[0016] If a master BMS detects a communication error during communication with multiple direct BMSs, the master BMS modifies the channel information of the direct BMS corresponding to the uplink frame where the communication error occurred, and then broadcasts the broadcast data containing the modified channel information through a common frequency channel.

[0017] The period of communication frames transmitted and received by the direct BMS and the master BMS, or the time interval between consecutive data frames, is variable depending on the driving conditions of the vehicle on which the battery module is installed.

[0018] To solve the above-mentioned problems, another aspect of the present invention is a method for diagnosing a battery cell performed in a battery cell diagnostic system located in a vehicle, wherein the battery cell diagnostic system includes a plurality of direct BMSs located in the vehicle and electrically connected to a plurality of battery cells included in a battery module, and a master BMS located in the vehicle and performing wireless communication with the direct BMS, the method for diagnosing the battery cell comprising the steps of: making physical and electrical direct contact between a port included in the battery cell connection section of the direct BMS and the exposed electrodes of each of the plurality of battery cells; measuring the voltage of each battery cell in the voltage measurement section of the direct BMS; and measuring the current of the battery cell or battery in the current measurement section of the direct BMS. The process includes the steps of measuring the current of a module and communicating wirelessly with a master BMS from a first wireless communication unit of a direct BMS, wherein the first wireless communication unit is connected to the MCU of the direct BMS, the master BMS sets a communication frequency channel for each of the direct BMSs located in the vehicle, broadcasts broadcast data containing channel information relating to the communication frequency channel for each direct BMS on a common frequency channel at a predetermined interval, the direct BMS is configured to receive the data transmitted on the common frequency channel, and transmits and receives information about its battery cell on its own communication frequency channel included in the broadcast data received on the common frequency channel with the master BMS. [Effects of the Invention]

[0019] According to the present invention, by configuring the direct BMS to make direct physical and electrical contact with multiple battery cells, it is possible to measure the voltage and current to multiple battery cells, thereby preventing noise generated by channel switching in conventional methods in which the battery and direct BMS are indirectly connected via cables, etc., and thereby increasing the reliability of the data measured for multiple battery cells.

[0020] Furthermore, according to the present invention, the direct BMS, by having a configuration that makes direct physical and electrical contact with each of the multiple battery cells, measures the voltage information for each of the multiple battery cells. This eliminates the conventional problem where noise occurs that cannot be corrected because a predetermined number of the multiple battery cells have different voltages, thereby enabling the acquisition of data with even higher reliability.

[0021] Furthermore, according to the present invention, a master BMS connected to each of the multiple battery modules and multiple direct BMSs perform asynchronous wireless communication, thereby solving problems such as reduced spatial efficiency, increased weight, and increased costs that arose when isolation elements (Isolators) to prevent electromagnetic interference were applied or installed at multiple locations in conventional wired communication systems.

[0022] Furthermore, according to the present invention, multiple direct BMSs and master BMSs connected to each of the multiple battery modules can perform asynchronous wireless communication by including a communication modem that modulates a digital signal with a differential phase-shift modulation signal or demodulates a differential phase-shift modulation signal with a digital signal. As a result, the structure of the communication module for performing asynchronous wireless communication is simple, but it has good frequency efficiency and enables stable wireless communication even in the special environment of a vehicle.

[0023] Also, according to the present invention, the battery module and the direct BMS are physically directly connected without a configuration such as a separate cable, etc., thereby improving the durability against vibration compared to the conventional vehicle battery management system. As a result, the reliability of the data measured even in a special measurement situation such as a high-speed driving environment is also increased.

[0024] Also, according to the present invention, by operating an independent common frequency channel that only performs downlink communication, the reliability of data transmission and reception can be ensured.

[0025] Also, according to the present invention, when an error occurs in communication, the time division information and channel information of the uplink frame of the direct BMS can be individually changed by its own error correction configuration, ensuring the reliability of the wireless communication system.

Brief Description of Drawings

[0026] [Figure 1] FIG. 1 is a diagram schematically showing the configuration of a battery cell diagnosis system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically showing the internal configuration of a direct BMS according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram schematically showing the internal configuration of a direct BMS according to another embodiment of the present invention. [Figure 4] FIG. 4 is a diagram schematically showing the configuration of a battery module and a battery cell connection part according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram schematically showing the internal configuration in which asynchronous wireless communication is performed by each of a direct BMS and a master BMS according to an embodiment of the present invention. [Figure 6] FIG. 6 is a diagram schematically showing the internal configuration of a first wireless communication part according to an embodiment of the present invention. [Figure 7] FIG. 7 is a diagram schematically showing the execution steps of a data transmission step performed by a modem transmission part and a Tx part according to an embodiment of the present invention. [Figure 8]Figure 8 is a schematic diagram showing the execution steps of the data reception step performed by the modem receiving unit and Rx unit according to one embodiment of the present invention. [Figure 9] Figure 9 is a schematic diagram showing the structure of a communication frame in asynchronous wireless communication between a master BMS and multiple direct BMS according to one embodiment of the present invention. [Figure 10] Figure 10 is a schematic diagram illustrating the process of processing information received from multiple direct BMSs in a master BMS according to one embodiment of the present invention. [Figure 11] Figure 11 is a schematic diagram showing the communication cycle which varies depending on the operating conditions of a vehicle equipped with a battery according to one embodiment of the present invention. [Figure 12] Figure 12 is a schematic diagram showing the configuration of a battery cell diagnostic system according to another embodiment of the present invention. [Figure 13] Figure 13 is a schematic diagram showing the communication status of a battery cell diagnostic system in a common frequency channel and a communication frequency channel according to one embodiment of the present invention. [Figure 14] Figure 14 is a schematic diagram showing the structure of a communication frame in a common frequency channel according to one embodiment of the present invention. [Figure 15] Figure 15 is a schematic diagram showing the structure of a communication frame in a communication frequency channel according to one embodiment of the present invention. [Figure 16] Figure 16 is a schematic diagram showing data broadcast on a common frequency channel according to one embodiment of the present invention. [Figure 17] Figure 17 is a schematic diagram showing data broadcast on a communication frequency channel according to one embodiment of the present invention. [Figure 18] Figure 18 is a schematic diagram illustrating the execution steps of the error correction configuration according to one embodiment of the present invention. [Modes for carrying out the invention]

[0027] Various embodiments and / or modes will be described below with reference to the drawings. In the following description, numerous specific details are disclosed for illustrative purposes to aid in the general understanding of one or more modes. However, it will be recognized by those ordinary skill in the art of the present invention that these modes can also be carried out without such specific details. The following description and accompanying drawings detail specific exemplary modes of one or more modes. However, these modes are illustrative, and some of the various methods of the principles of various modes are available, and the description is intended to include all such modes and their equivalents.

[0028] Furthermore, various forms and characteristics are presented by systems that may include numerous devices, components, and / or modules. It should be understood and recognized that various systems may include further devices, components, and / or modules, or they may not include all of the devices, components, and modules discussed in connection with the drawings.

[0029] The terms "embodiments," "examples," "modes," and "exemplifications" used herein do not necessarily imply that any mode or design described is better or more advantageous than other modes or designs. The terms "~part," "component," "module," "system," and "interface" used below generally refer to computer-related entities, such as hardware, hardware-software combinations, and software.

[0030] Furthermore, the terms “includes” and / or “includes” should be understood to mean that the feature and / or component in question is present, but not to exclude the presence or addition of one or more other features, components, and / or groups thereof.

[0031] Furthermore, terms including ordinal numbers, such as "first," "second," etc., are used to describe various components, but the components are not limited by such terms. The terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may be referred to as the first component. The terms "and" and / or include a combination of multiple related items, or any of the multiple related items.

[0032] Furthermore, in embodiments of the present invention, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those with ordinary skill in the art to which the present invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as ideally or excessively formal unless explicitly defined in embodiments of the present invention.

[0033] 1. Diagnostic system and method for battery cells using asynchronous wireless communication The following describes an invention that transmits and receives data between a master BMS and a direct BMS using a differential phase-shift modulation signal, which is an asynchronous wireless communication signal.

[0034] Figure 1 is a schematic diagram showing the configuration of a battery cell diagnostic system according to one embodiment of the present invention.

[0035] Specifically, the battery cell diagnostic system of the present invention senses multiple pieces of information about a battery installed inside a vehicle that uses battery power as its propulsion system, and diagnoses the battery based on the sensed information. As shown in Figure 1, the diagnostic system includes a plurality of direct BMS 1000 (1000.1 to 1000.N) and a master BMS 2000, and the master BMS 2000 is characterized by communicating wirelessly with each of the plurality of direct BMS 1000. That is, in Figure 1, solid lines indicate locations that are physically connected or in contact, and dotted lines indicate configurations that are wirelessly connected.

[0036] The diagnostic system is electrically connected to a battery located in the vehicle and can measure several indicators for managing the battery. These indicators include voltage, current, and temperature. The battery connected to the diagnostic system of the present invention, as described below, has a configuration including a battery module containing multiple battery cells and a battery pack having multiple battery modules, according to known technology, but is not limited thereto; the present invention can be applied to any battery containing multiple battery cells.

[0037] More specifically, each of the multiple direct BMS 1000s is electrically connected to multiple battery cells and can measure the voltage, current, and temperature of the connected battery cells. As shown in Figure 1, in one embodiment of the present invention, each of the multiple direct BMS 1000s is electrically connected to one battery module. On the other hand, in another embodiment of the present invention, the unit of multiple battery cells connected to each of the multiple direct BMS 1000s is not limited to a battery module, and the unit can be set to a battery cell group consisting of a predetermined number of battery cells.

[0038] In the following description, we will explain based on a configuration in which each of the multiple direct BMS 1000s is connected to each of the multiple battery modules, and it is desirable that the number of multiple direct BMS 1000s provided in the diagnostic system of the present invention corresponds to the number of battery modules contained in the battery.

[0039] Information sensed by each of the multiple direct BMS 1000 units from the battery module to which it is connected is transmitted to the master BMS 2000 by a first wireless communication unit 1600 (see Figure 2) included in each of the multiple direct BMS 1000 units. The master BMS 2000 then diagnoses the state of the battery based on the information received from each of the multiple direct BMS 1000 units. The hardware configuration of the battery cell diagnostic system of the present invention and the configuration of communication between the direct BMS 1000 and the master BMS 2000 will be described in detail below.

[0040] Figure 2 schematically shows the internal configuration of a direct BMS 1000 according to one embodiment of the present invention, and Figure 3 schematically shows the internal configuration of a direct BMS 1000 according to another embodiment of the present invention.

[0041] As shown in Figures 2 and 3, the diagnostic system for battery cells located inside a vehicle includes a plurality of direct BMS 1000 located inside the vehicle and electrically connected to a plurality of battery cells included in a battery module, and a master BMS 2000 located inside the vehicle and performing wireless communication with the direct BMS 1000, wherein the direct BMS 1000 includes a battery cell connection section 1100 having ports that directly physically and electrically contact the exposed electrodes of each of the plurality of battery cells, a voltage measuring section 1200 electrically connected to the battery cell connection section 1100 and measuring the voltage of each battery cell in a circuit configuration, a current measuring section 1300 electrically connected to the battery cell connection section 1100 and measuring the current of a battery cell or battery module in a circuit configuration, an MCU 1500, and a first wireless communication section 1600 connected to the MCU 1500 and performing wireless communication with the master BMS 2000.

[0042] Specifically, the battery cell connection section 1100 includes multiple ports, and each port is directly and physically connected to the electrodes of the multiple battery cells connected to the direct BMS 1000, without the need for separate cables or other configurations. This configuration can resolve the following problems of the conventional technology.

[0043] In conventional battery management systems, multiple battery cells are grouped together, and the signal output lines of the grouped battery cells are connected to a single slave BMS. For example, if a battery module has 25 battery cells, the 25 battery cells are grouped into five groups of five, and the voltage and current of the entire group of five battery cells are measured and transmitted to the slave BMS via a separate wired communication. Furthermore, since the signals transmitted from each of the five signal lines cannot be transmitted to the slave BMS simultaneously, a channel switching module was required between the five signal lines and the slave BMS.

[0044] Therefore, one slave BMS receives information from 25 battery cells using a total of 5 signal lines, and in this process, there was a problem of noise being generated by the switching module. Furthermore, in a battery management system with such a configuration, in order to prevent electromagnetic interference (Electro-Magnetic Inference) between multiple signal lines, it is required that isolators for separating signal components be applied or installed at multiple locations.

[0045] In other words, to solve the problem of switching noise occurring in the conventional technology or due to isolation elements, the present invention has a battery cell connection section 1100 in which each of the multiple ports and each of the electrodes of the multiple battery cells are in physical direct contact. A detailed explanation of the configuration of the battery cell connection section 1100 will be described later in Figure 4.

[0046] The direct BMS 1000 includes a voltage measuring unit 1200, a current measuring unit 1300, and a temperature measuring unit 1400. The voltage measuring unit 1200 is configured in a circuit and measures the voltage of each of the multiple battery cells included in the battery module connected to the direct BMS 1000 via the battery cell connection unit 1100. More specifically, as shown in Figure 3, the battery cell connection unit 1100 includes a plurality of voltage measuring ports, where the number of voltage measuring ports corresponds to the number of battery cells included in the battery module, and the voltage measuring unit 1200 can measure the voltage of each of the battery cells in the corresponding battery module via each of the voltage measuring ports. Here, the voltage to be measured is measured based on a RAW form voltage signal for each of the battery cells, and the RAW form signal means an electrical signal that is not interfered with or distorted by external factors. In other words, the voltage measurement unit 1200 measures accurate voltage information for each of the multiple battery cells based on the RAW voltage signals of each of the multiple battery cells received by the multiple voltage measurement ports, and then transmits this information to the MCU 1500. The MCU 1500 then transmits the received voltage information to the master BMS 2000 using wireless communication.

[0047] Furthermore, the voltage measurement unit 1200 is connected to a high-voltage alarm module (not shown) and a low-voltage alarm module (not shown), so that if the voltage of one or more specific battery cells is higher or lower than a predetermined standard, the high-voltage alarm module or the low-voltage alarm module can immediately generate an alarm message, which can then be transmitted to the master BMS 2000 by the first wireless communication unit 1600.

[0048] The current measuring unit 1300 is configured in a circuit and measures the current of the battery module connected to the direct BMS 1000 via a single current measuring port. More specifically, the current measuring port is located at the output terminal of the battery module or battery cell group connected to the direct BMS 1000, and it is desirable that the current measuring unit 1300 be in direct electrical and physical contact with the battery module.

[0049] The current measured via the current measurement port is measured based on a RAW current signal for the battery module, and as described above, the RAW signal means an electrical signal that is not interfered with or distorted by external factors. That is, the current measurement unit 1300 measures accurate current information for the battery module based on the RAW current signal for the battery module received via the current measurement port, and then transmits this to the MCU 1500, which in turn transmits the received voltage information to the master BMS 2000 via wireless communication.

[0050] Furthermore, the current measurement unit 1300 is connected to an overcurrent alarm module (not shown), and if the current of the battery module is higher than a predetermined standard, the overcurrent alarm module can immediately generate an alarm message, which can then be transmitted to the master BMS 2000 by the first wireless communication unit 1600.

[0051] On the other hand, according to another embodiment of the present invention, the battery cell connection section 1100 includes a plurality of current measurement ports, and the plurality of current measurement ports are connected to each of the battery cells, similar to the plurality of voltage measurement ports in Figure 3, so that the current of each of the plurality of battery cells can be measured. However, this specification will describe an embodiment in which a single current measurement port is provided in one direct BMS 1000.

[0052] The temperature measuring unit 1400 is provided inside the direct BMS 1000 together with the voltage measuring unit 1200 and the current measuring unit 1300, and includes a temperature sensor. The temperature measuring unit 1400 can measure the temperature of the substrate on which the direct BMS 1000 is installed using the temperature sensor. According to one embodiment of the present invention, the temperature measuring unit 1400 is connected to an external temperature sensor, and the external temperature sensor can measure the temperature of a battery module or the like connected to the direct BMS 1000 and transmit the measurement result to the temperature measuring unit 1400.

[0053] The temperature measurement unit 1400 transmits the measurement result for the battery module to the MCU 1500, and the MCU 1500 transmits the result to the master BMS 2000 via the first wireless communication unit 1600. The temperature measurement unit 1400 is connected to an overheat alarm module (not shown) so that if the temperature measured by the temperature measurement unit 1400 is higher than a predetermined standard, the overheat alarm module can immediately generate an alarm message and transmit it to the master BMS 2000 via the first wireless communication unit 1600. The temperature measurement unit 1400 is also connected to the voltage measurement unit 1200 so that it can use a portion of the power drawn to the voltage measurement unit 1200.

[0054] As described above, the MCU 1500 receives the results measured by the voltage measurement unit 1200, the current measurement unit 1300, and the temperature measurement unit 1400, processes the data, and transmits it to the first wireless communication unit 1600. It also controls each of the direct BMS 1000, including the voltage measurement unit 1200, the current measurement unit 1300, and the temperature measurement unit 1400.

[0055] The first wireless communication unit 1600 is connected to the MCU 1500 and performs wireless communication with the master BMS 2000. As shown in Figure 3, the first wireless communication unit 1600 includes a modem unit 1610 and a transceiver unit 1620. To transmit data received from the MCU 1500 to the master BMS 2000, it performs a data transmission step (S10-S13, see Figure 7) in which it modulates the binarized data received from the MCU 1500 with a phase-shift modulation signal, modulates the phase-shift modulation signal with a differential phase-shift modulation signal, and transmits it externally. To receive data from the master BMS 2000, it performs a data reception step (S20-S25, see Figure 8) in which it demodulates the differential phase-shift modulation signal received by the first antenna unit 1700 with a phase-shift modulation signal, demodulates the decoded phase-shift modulation signal with binarized data, and transmits it to the MCU 1500. The first wireless communication unit 1600 will be explained in more detail in the explanations of Figures 5 to 8.

[0056] The first antenna unit 1700, connected to the first wireless communication unit 1600, is configured as a circuit. The first antenna unit 1700 receives signals modulated by the first wireless communication unit 1600 and broadcasts them externally, or receives signals broadcast by the master BMS 2000 and transmits them to the first wireless communication unit 1600. The signals broadcast by the first antenna unit 1700 can be received by the second antenna of the master BMS 2000, as shown in Figure 5. In a preferred embodiment, the antenna included in the first antenna unit 1700 can transmit and receive radio waves in the 900 MHz band.

[0057] Figure 4 schematically shows the configuration of a battery module and a battery cell connection unit 1100 according to one embodiment of the present invention.

[0058] As shown in Figure 4, both the positive and negative terminals of the battery cell are in direct contact with ports provided in the battery cell connection section 1100, and the voltage measuring section 1200 is connected to each of the ports to measure the voltage for each battery cell.

[0059] Specifically, as described above, the voltage measurement unit 1200 of the direct BMS 1000 can receive raw voltage signals for each of the multiple battery cells included in the battery module connected to the direct BMS 1000 via the multiple voltage measurement ports included in the battery cell connection unit 1100, and measure the accurate voltage of each battery cell.

[0060] More specifically, the battery modules have multiple battery cells connected in series with each other, and in a preferred embodiment, the battery modules have their positive (+) and negative (-) electrodes crossed. The exposed positive (+) and negative (-) electrodes of each battery cell are in direct physical and electrical contact with the positive (+) and negative (-) contacts of the battery cell connection 1100, respectively. That is, the positive (+) electrode of a battery cell is effectively one configuration directly connected to the positive (+) contact located within the battery cell connection 1100, and the negative (-) electrode of a battery cell is effectively one configuration directly connected to the negative (-) contact located inside the battery cell connection 1100.

[0061] Furthermore, as shown in Figure 3, each of the multiple voltage measurement ports connected to the voltage measurement unit 1200 has a configuration in which it is directly in contact, both physically and electrically, with one (+) contact and one (-) contact simultaneously. With this configuration, each of the multiple voltage measurement ports receives a RAW voltage signal for each of the battery cells, and the voltage measurement unit 1200 can accurately measure the voltage for the corresponding battery cell based on the received RAW voltage signal.

[0062] In other words, unlike conventional battery management system technologies, there is no interference or loss in the process of data or signals originating from the battery cell reaching the slave BMS. Therefore, the RAW voltage signal can be immediately transmitted to the direct BMS 1000, and the voltage measurement unit 1200 inside the direct BMS 1000 can accurately measure the voltage based on the RAW voltage signal. Thus, the above configuration has the effect of eliminating the electromagnetic interference isolation element (EMI Isolator) that was included in conventional battery management systems.

[0063] On the other hand, as shown in Figure 3, the current measurement port of the battery cell connection part 1100 is also in direct physical and electrical contact with the battery module, so that the RAW current signal can be immediately transmitted to the direct BMS 1000, and the current measurement unit 1300 inside the direct BMS 1000 can accurately measure the current based on the RAW current signal.

[0064] Furthermore, in one embodiment of the present invention, the voltage measuring unit 1200 and the current measuring unit 1300 can measure the voltage and current of a battery cell over time and transmit the waveform of the output voltage and the waveform of the output current of the battery cell over time to the MCU 1500.

[0065] Furthermore, the direct BMS1000 configuration, which is directly connected to the battery module, allows for the derivation of the individual impedance of multiple battery cells. By deriving these individual impedances, it is possible to individually detect abnormal battery cells within the battery module. For example, problems such as fires caused by imbalances in voltage between multiple battery cells can be prevented early on. This represents an improvement over conventional techniques that measure the average voltage within the battery module.

[0066] Figure 5 schematically shows the internal configuration of asynchronous wireless communication performed in the direct BMS1000 and master BMS2000 according to one embodiment of the present invention.

[0067] As shown in Figure 5, each of the multiple direct BMS 1000s includes a first wireless communication unit 1600 and a first antenna unit 1700 for wireless communication with the master BMS 2000, and the master BMS 2000 includes a second wireless communication unit 2200 and a second antenna unit 2300 for wireless communication with each of the multiple direct BMS 1000s. The first wireless communication unit 1600 is connected to the MCU 1500 and receives information from the voltage measurement unit 1200, the current measurement unit 1300, and the temperature measurement unit 1400, and the second wireless communication unit 2200 is connected to the control unit 2100 and transmits data received from the multiple direct BMS 1000s to the control unit 2100.

[0068] The control unit 2100 includes one or more memories and one or more processes, and can diagnose the state of the entire battery module or each of the battery cells connected to the plurality of direct BMS 1000 based on the data received by the second wireless communication unit 2200. In one embodiment of the present invention, the control unit 2100 can determine the state of the entire battery installed in the vehicle based on the diagnosis results for the state of the battery module or battery cells. For example, the control unit 2100 can derive the possibility of a fire occurring during charging, or, while driving, can derive the remaining driving distance in real time by considering the current driving state and battery state.

[0069] Furthermore, the control unit 2100 can broadcast control information for each of the multiple direct BMS 1000s via the second wireless communication unit 2200 and the second antenna unit 2300. A more detailed explanation of the wireless communication between the master BMS 2000 and the multiple direct BMS 1000s will be given later in the explanation of Figures 9 to 10.

[0070] Figure 6 schematically shows the internal configuration of the first wireless communication unit 1600 according to one embodiment of the present invention.

[0071] As shown in Figure 6, the first wireless communication unit 1600 includes a modem unit 1610 and a transceiver unit 1620. The modem unit 1610 includes a modem transmission unit 1611 that modulates information transmitted from the MCU 1500 for transmission to the master BMS 2000, and a modem reception unit 1612 that demodulates signals received from the master BMS 2000 for transmission to the MCU 1500. The transceiver unit 1620 includes a Tx unit 1621 that includes a configuration for broadcasting the signal modulated by the modem transmission unit 1611 using a first antenna unit 1700, and an Rx unit 1622 that includes a configuration for processing the signal received by the first antenna unit 1700.

[0072] More specifically, the modem transmitting unit 1611 includes a hardware and / or software configuration that modulates digital data received from the MCU 1500 with a phase-shift-modulation signal (PSMS) and modulates the phase-shift-modulation signal (PSMS) with a differential phase-shift-modulation signal (DPSMS). The modem receiving unit 1612 includes a hardware and / or software configuration that demodulates the received differential phase-shift-modulation signal (DPSMS) with a phase-shift-modulation signal (PSMS) and demodulates the demodulated phase-shift-modulation signal (PSMS) with a digital signal. A more detailed explanation of the data transmission steps (S10-S13) and data reception steps (S20-S25) performed by the modem unit 1610 will be explained in more detail in the explanation with respect to Figures 7-8.

[0073] On the other hand, the Tx section 1621 includes a hardware and / or software-configured filter for processing the signal modulated by the modem transmission section 1611, and a DAC (Digital to Analogue Converter), and the Rx section 1622 includes a hardware and / or software-configured filter for processing the signal received by the first antenna section 1700, and an ADC (Analogue to Digital Converter), and the like.

[0074] In other words, information transmitted from the MCU 1500 of the direct BMS 1000 is transmitted to the first antenna unit 1700 via the modem transmission unit 1611 and the Tx unit 1621, and can be transmitted to the master BMS 2000. Information transmitted from the control unit 2100 of the master BMS 2000 is received by the first antenna unit 1700, and transmitted to the MCU 1500 via the Rx unit 1622 and the modem reception unit 1612.

[0075] Thus, the present invention adopts a configuration in which a master BMS and multiple direct BMSs perform asynchronous wireless communication, enabling more stable wireless communication in environments where the Line of Sight (LOS) cannot be ensured due to aluminum shielding or the like inside an automobile battery pack.

[0076] Furthermore, by adopting the above-mentioned configuration and excluding the configuration of communication stations that would be passed through in the middle, as adopted in conventional battery management systems including slave BMS or module BMS, a simpler wireless communication system configuration can be achieved.

[0077] Figure 7 schematically shows the execution steps of the data transmission steps (S10 to S13) performed by the modem transmission unit 1611 and Tx unit 1621 according to one embodiment of the present invention.

[0078] As described above, the information transmitted from the MCU 1500 of the direct BMS 1000 is transmitted to the first antebec via the modem transmission unit 1611 and the Tx unit 1621, and then transmitted to the master BMS 2000. The following describes the data transmission steps (S10 to S13) in which the data processed by the MCU 1500 is transmitted to the master BMS 2000.

[0079] Specifically, as shown in Figure 7, when the modem transmission unit 1611 receives a binarized digital signal from the MCU 1500, the modem transmission unit 1611 inserts an error detection code into the message consisting of the received digital signal (S10). The error detection code is a code used in the process of being received by the master BMS 2000, and preferably has a size of 16 bits.

[0080] Thereafter, the modem transmission unit 1611 modulates the message into which the error detection code has been inserted with a phase-shifted modulation signal (PSMS) in step (S11). The phase-shifted modulation signal (PSMS) is a signal modulated in a manner that changes the phase of the carrier wave according to the information value of the digital message. Thereafter, the modem transmission unit 1611 modulates the phase-shifted modulation signal (PSMS) with a differential phase-shifted modulation signal (DPSMS) in step (S12). Step S12 is a configuration for solving the problem of phase-shifted modulation signals (PSMS) that can only be detected synchronously, and the differential phase-shifted modulation signal (DPSMS) is a signal that is differentially encoded in a manner that uses a phase-shifted modulation signal (PSMS) from a predetermined section prior as a reference wave for detection, so that the phase difference between the preceding and succeeding signal sections corresponds to the information to be modulated.

[0081] In other words, the differential phase-shifted modulation signal (DPSMS) does not store information in the absolute phase of the carrier wave, but rather in the relative phase difference between adjacent bit intervals. This allows for the determination of information by distinguishing whether the signal phase in the current bit interval is the same as or different from the phase in the previous bit interval.

[0082] For example, when transmitting an information bit "1", modulation can be performed in a manner that maintains the output logic value the same as before, and when attempting to transmit an information bit "0", modulation can be performed in a manner that changes the output logic value differently from before. In order to perform steps S11 and S12, the modem transmission unit 1611 includes configurations such as a delay circuit, amplitude level shifter, and product modulator, which are implemented in hardware or software.

[0083] Thus, when wireless communication is performed via the differential phase-shifted modulation signal (DPSMS), synchronization is unnecessary, and therefore no separate configuration or program is required for synchronization. Subsequently, the Tx unit 1621 uses the already installed filter to increase the resolution of the differential phase-shifted modulation signal (DPSMS) received from the modem transmission unit 1611 (S13), converts the signal that has passed through the filter into an analog signal using another configuration (e.g., an ADC), and propagates it through the first antenna unit 1700.

[0084] Furthermore, although the master BMS and direct BMS frequently transmit and receive data, the size of the data is not large, so a communication system that is bulky or consumes a lot of power is unnecessary. Considering the lifespan of the vehicle, a simple and stable communication system is desirable, and the wireless communication system used in the present invention is characterized by satisfying all of the above conditions.

[0085] Furthermore, referring to Figure 5, the second wireless communication unit 2200 of the master BMS 2000 includes a configuration similar to that of the first wireless communication unit 1600 for performing the data transmission steps (S10 to S13) described above. With this configuration of the second wireless communication unit 2200, differential phase shift modulation signals (DPSMS) are transmitted to multiple direct BMS 1000s.

[0086] Figure 8 schematically shows the execution steps of the data reception step (S20-S25) performed by the modem receiving unit 1612 and Rx unit 1622 according to one embodiment of the present invention.

[0087] In general terms, as described above, the signal broadcast by the master BMS2000 is received by the first antenna unit 1700, transmitted to the Rx unit 1622 and the modem receiving unit 1612, and then transmitted to the MCU 1500 of the direct BMS1000. The following describes the data reception steps (S20~S25) in which the data received by the first antenna unit 1700 is transmitted to the MCU 1500.

[0088] Specifically, as shown in Figure 8, the Rx unit 1622 converts the signal received by the first antenna unit 1700 into a digital signal using another configuration (e.g., a DAC), and then performs a step (S20) to reduce the sampling rate. More specifically, step S20 reduces the sampling rate by averaging the sampled signal for predetermined intervals, thereby improving the resolution of the received signal. Here, the signal received by the first antenna unit 1700 also corresponds to a differential phase-shift modulated signal (DPSMS), and the differential phase-shift modulated signal (DPSMS) received by the first antenna unit 1700 corresponds to the signal modulated by the second wireless communication unit 2200 of the master BMS 2000 in the same manner as the data transmission steps (S10-S13) described in the explanation with respect to Figure 7.

[0089] Thereafter, the Rx unit 1622 performs a step (S21) to increase the resolution of the differential phase-shifted modulation signal (DPSMS) with a reduced sampling rate using the already installed filter, and the modem receiver unit 1612 performs a step (S22) to derive the starting point of the signal after step S21. Once the starting point of the differential phase-shifted modulation signal (DPSMS) is derived in step S22, the modem receiver unit 1612 performs a step (S23) to differentially decode the signal and demodulate it with a phase-shifted modulation signal (PSMS), and then performs a step (S24) to demodulate the demodulated phase-shifted modulation signal (PSMS) with a digital signal consisting of 0s or 1s.

[0090] After the signal received by the first antenna unit 1700 is demodulated as a digital signal, the modem receiving unit 1612 performs a step (S25) to detect a communication error in the signal using an error detection code. The error detection code corresponds to a code shared by the master BMS 2000 and the direct BMS 1000. If it is determined that there is an error in the received signal, the direct BMS 1000 can wait to re-receive the message or send a request to the master BMS 2000 to retransmit the message. If it is determined that there is no error in the received signal, the modem receiving unit 1612 transmits the signal to the MCU 1500.

[0091] As described above in the explanation of Figure 7, the present invention is characterized in that wireless communication between the master BMS2000 and the direct BMS1000 is performed via a differential phase-shift modulation signal (DPSMS), and therefore no other configuration or program is required for detecting synchronization in the execution steps S20 to S25.

[0092] Furthermore, when wireless communication is performed using the modulation / demodulation method of the present invention, its structure is simpler and it uses a narrower bandwidth compared to wireless communication systems using other modulation / demodulation methods. Therefore, optimized wireless communication can be performed in harsh environments where space is limited and weight is restricted, such as vehicle batteries. As one embodiment of the present invention, the wireless communication system of the present invention has good frequency efficiency and can use dozens of 200kHz narrowband channels, thereby enabling one-to-many communication such as master BMS2000-direct BMS1000 even with a small bandwidth.

[0093] Furthermore, as shown in Figure 5, the second wireless communication unit 2200 of the master BMS 2000 includes a configuration similar to that of the first wireless communication unit 1600 for performing the data reception steps (S20 to S25) described above. With this configuration of the second wireless communication unit 2200, the master BMS 2000 can receive the differential phase shift modulation signal (DPSMS) transmitted from the direct BMS 1000 and determine the status of the battery module or multiple battery cells connected to the direct BMS 1000.

[0094] Figure 9 schematically shows the structure of a communication frame in asynchronous wireless communication between a master BMS 2000 and a plurality of direct BMS 1000 according to one embodiment of the present invention, and Figure 10 schematically shows the process of processing information received from a plurality of direct BMS 1000 in the master BMS 2000 according to one embodiment of the present invention.

[0095] As shown in Figures 9 to 10, the first wireless communication unit 1600 enables a communication frame of a wireless communication channel in which multiple direct BMS 1000s send and receive data with the master BMS 2000. This frame includes a subframe which contains a downlink frame that the master BMS 2000 broadcasts to the multiple direct BMS 1000s, and multiple uplink frames that each of the multiple direct BMS 1000s transmits to the master BMS 2000. In the subframe, the downlink frame and the multiple uplink frames are each temporally separated.

[0096] Furthermore, the data received by multiple direct BMS 1000s via the downlink frame includes identifier information for each direct BMS 1000 and time-division multiplexing information for the uplink frame relating to the direct BMS 1000 having the corresponding identifier information. Each direct BMS 1000 then transmits the data to the master BMS 2000 via the uplink frame assigned to it, based on the time-division multiplexing information for its own uplink frame included in the data received via the downlink frame.

[0097] Furthermore, the wireless communication channel is configured such that, temporally, multiple uplink frames are arranged after a downlink frame according to a predetermined rule. The data broadcast in the downlink frame includes request information for the target to be transmitted from each direct BMS 1000. Each direct BMS 1000 generates response information in accordance with the request information contained in the data broadcast in the downlink frame and transmits the data including the response information to the master BMS 2000 using the time-division multiplexing information of its own uplink frame.

[0098] Furthermore, the communication frame of the wireless communication channel includes multiple identical subframes, and the master BMS2000 ultimately determines the received data based on the multiple identical uplink frames it receives.

[0099] Specifically, in one embodiment of the present invention, the communication frame (=1 frame) corresponding to the wireless communication cycle between the direct BMS 1000 and the master BMS 2000 can be set to a length of 100ms. In a typical automobile, the data transmission and reception cycle corresponds to 100ms, and the response time of the multiple sensor nodes connected to the direct BMS 1000 has a cycle of 100ms. Therefore, it is most desirable to set the length of the communication frame to 100ms, which allows for the fastest possible determination of the state of each of the multiple battery cells.

[0100] On the other hand, as shown in Figure 9, by performing four repeated communications within a single communication frame, communication errors can be addressed and communication stability can be increased, and the period of these repeated communications is defined as a subframe. The subframe includes a downlink frame to which communication from the master BMS2000 to the direct BMS1000 (downlink communication) is assigned, and an uplink frame to which communication from the direct BMS1000 to the master BMS2000 (uplink communication) is assigned.

[0101] The downlink frame corresponds to the time allocated for the master BMS 2000 to broadcast to multiple direct BMS 1000s, and the multiple direct BMS 1000s prepare for data reception steps (S20~S25) during that time. In the downlink frame, the signal broadcast by the master BMS 2000 includes the identifier information of each of the multiple direct BMS 1000s and the time-division multiplexing information of the uplink frame relating to the direct BMS 1000 having the identifier information.

[0102] For example, the data broadcast by the master BMS2000 in a downlink frame includes information that includes identifier information for direct BMS#1(1000.1) and a first time based on the identifier information of direct BMS#1(1000.1), and a second time based on identifier information for direct BMS#2(1000.2) and the identifier information of direct BMS#2(1000.2). Direct BMS#1(1000.1), upon receiving the data broadcast by the master BMS2000, performs a data transmission step (S10~S13) in accordance with the first time, and direct BMS#2(1000.2) performs a data transmission step (S10~S13) in accordance with the second time. On the other hand, the data broadcast by the master BMS2000 may further include identifier information for each direct BMS1000, as well as request information, command information, or control information based on the identifier information. Upon receiving this data, the direct BMS1000 generates response information corresponding to the received request information, command information, or control information, and transmits it to the master BMS2000.

[0103] On the other hand, the number of subframes included in one communication frame shown in Figure 9, the period of the subframes, the period of the uplink frame, and the period of the downlink frame, etc., fall under one embodiment of the present invention and are items that can be modified according to the designer's intentions.

[0104] In one embodiment of the present invention, as shown in Figure 9, if there are a total of 25 direct BMS 1000s, one subframe consists of one downlink frame and 25 uplink frames. Here, it is desirable that each uplink frame be assigned to each of the multiple direct BMS 1000s, and that they are assigned to different time zones. That is, the information regarding the time zone to which each of the multiple uplink frames is assigned is defined as time-division information.

[0105] Furthermore, if communication is repeated a total of four times for one communication frame, one communication frame (=100ms) contains four subframes (=25ms*4=100ms), and one subframe (=25ms) contains one downlink frame (=5ms) and a total of 25 uplink frames (=0.8ms*25=20ms).

[0106] In summary, the wireless communication system adopted in the present invention is a system in which, when a master BMS 2000 simultaneously sends a message to multiple direct BMS 1000s, each of the multiple direct BMS 1000s that receive the message sends data to the master BMS 2000 using the uplink frame assigned to it. Conventional wireless communication systems used in battery diagnostic technology have a lot of uplink communication, so the communication frame is mainly composed of uplink frames. However, the present invention adopts a structure in which the downlink frame is placed at the beginning of the communication frame, thereby ensuring the reliability of data transmission and reception at an early stage and enabling more efficient use of the communication bandwidth.

[0107] Furthermore, the wireless communication system adopted in the present invention is optimized for the data size and number of nodes required when transmitting and receiving battery information in real time in a vehicle that uses battery power as its propulsion system. This system has the effect of providing the user with information about the vehicle's battery quickly and accurately, even when the vehicle is stopped, charging, or in motion.

[0108] Figure 10 shows one embodiment in which the master BMS2000 determines the status of multiple battery modules based on information received over one cycle (=100ms). For the sake of explanation, only the temperature information is shown among the information requested by the master BMS2000 from each direct BMS1000.

[0109] As shown in Figures 9 to 10, the master BMS 2000 can send four messages to multiple direct BMS 1000s during one cycle, each of which is contained in a downlink frame within subframes #1 to #4, where the four messages may be the same message. The 25 direct BMS 1000s that receive the message sent by the master BMS 2000 send information about the battery connected to them to their assigned uplink frame, based on the identifier information and time-division multiplexing information contained in the message.

[0110] In this case, if the master BMS2000 receives the same information in all uplink frames (Slot#1) in subframes #1 to #4, such as direct BMS#1(1000.1) assigned to Slot#1, the master BMS2000 will determine that the temperature of battery module #1 connected to direct BMS#1(1000.1) is 32°C.

[0111] On the other hand, if the master BMS2000 receives data normally in the uplink frame (Slot#2) of subframe #1, but not normally in the uplink frames (Slot#2) of subframes #2 to #4, such as direct BMS#2(1000.2) assigned to Slot#2, the master BMS2000 can determine the temperature of direct BMS#2(1000.2) to be 31°C based on the information received in the uplink frame (Slot#1) of subframe #1.

[0112] According to one embodiment of the present invention, if a data communication error occurs more than a predetermined number of times, such as in direct BMS#2(1000.2), the master BMS2000 can take measures such as causing direct BMS#2(1000.2) to change the slot of the uplink frame or change the frequency channel.

[0113] Furthermore, when other information is received in each uplink frame (Slot#25) of subframes #1 to #4, such as in the direct BMS#25 (1000.25) assigned to Slot#25, the master BMS2000 can, in one embodiment of the present invention, determine the information of the battery module based on the information received in the uplink frame (Slot#25) of subframe #4, which corresponds to the last received information out of the four pieces of information received. In another embodiment of the present invention, the information of the battery module can be determined based on the most frequently occurring information out of the four pieces of information received in subframes #1 to #4. In yet another embodiment of the present invention, the information of the battery module can be determined based on the average value of the four pieces of information received in subframes #1 to #4. On the other hand, the present invention is not limited to the embodiments described above and can be applied by ordinary engineers by design modifications using known techniques.

[0114] Figure 11 is a schematic diagram showing the communication cycle which varies depending on the operating conditions of a vehicle equipped with a battery according to one embodiment of the present invention.

[0115] As shown in Figure 11, the period of the communication frames of the wireless communication channel between the direct BMS 1000 and the master BMS 2000, or the time interval between consecutive communication frames, is varied depending on the driving conditions of the vehicle in which the battery module is installed.

[0116] Specifically, the present invention is a diagnostic system for a battery installed in a vehicle, characterized in that the communication cycle between the master BMS 2000 and the direct BMS 1000 is varied depending on the vehicle's driving conditions.

[0117] More specifically, Case 1 in Figure 11 shows the period of communication frames during driving. Since the battery status must be checked in real time during driving, no additional time intervals are added between continuous communication frames so that the master BMS2000 and direct BMS1000 can communicate wirelessly continuously.

[0118] On the other hand, Case 2 shows the period of communication frames when the vehicle is parked. When the vehicle is parked, there is no need to check the battery status in real time, so power consumption can be minimized by adding a time interval between consecutive communication frames, as shown in Figure 11.

[0119] Furthermore, in situations different from Cases 1 and 2, such as during charging, the communication frame period can be set to a period other than those shown in Figure 11. In one embodiment of the present invention, when performing updates / debugging on a diagnostic system, such as an OTA (Over The Air) update, the communication frame can be composed of only downlink frames without uplink frames.

[0120] 2. Diagnostic system and method for battery cells that support one-to-many wireless communication using a common frequency channel and multiple communication frequency channels.

[0121] The following describes a wireless communication system in a diagnostic system to which the invention described in 1. Asynchronous Wireless Communication for Battery Cell Diagnostic System and Method above is applied. The wireless communication system is characterized in that it independently operates a common frequency channel and a communication frequency channel in a 900 MHz frequency band having a predetermined bandwidth, and the master BMS and multiple direct BMS included in the diagnostic system stably perform wireless communication.

[0122] Figure 12 schematically shows the configuration of a battery cell diagnostic system applied to an electric vehicle according to one embodiment of the present invention.

[0123] As shown in Figure 12, the diagnostic system for battery cells located inside a vehicle includes a plurality of direct BMS 1000 located inside the vehicle and electrically connected to a plurality of battery cells included in a battery module, and a master BMS 2000 located inside the vehicle and performing wireless communication with the direct BMS 1000, wherein the direct BMS 1000 includes a battery cell connection section having ports that directly contact the exposed electrodes of each of the plurality of battery cells physically and electrically, a voltage measuring section electrically connected to the battery cell connection section and measuring the voltage of each battery cell in a circuit configuration, a current measuring section electrically connected to the battery cell connection section and measuring the current of a battery cell or battery module in a circuit configuration, an MCU, and a first wireless communication section connected to the MCU and performing wireless communication with the master BMS 2000.

[0124] In general terms, Figure 12 shows an embodiment in which the battery cell diagnostic system shown in Figure 1 is applied to a battery mounted on an electric vehicle, as one embodiment of the present invention. Similar to Figure 1, in Figure 12, solid lines indicate relationships that are physically directly in contact and electrically connected, while dotted lines indicate relationships that transmit and receive data wirelessly.

[0125] Specifically, the electric vehicle to which the embodiment shown in Figure 12 is applied includes a battery pack containing 500 battery modules, each containing 8 battery cells. In such a vehicle, the diagnostic system of the present invention is configured such that each of the multiple direct BMS 1000 (1000.1 to 1000.500) is directly connected to a battery module, both physically and electrically, and each direct BMS 1000 wirelessly transmits information about each or all of the battery cells of the connected battery module to a single master BMS 2000.

[0126] As shown in Figure 5, each of the multiple direct BMS 1000s includes a first wireless communication unit 1600 (1600.1 to 1600.500), and the master BMS 2000 includes a second wireless communication unit 2200. Each first wireless communication unit 1600 communicates wirelessly with the second wireless communication unit 2200 via asynchronous wireless signals (DPSMS).

[0127] On the other hand, the first wireless communication unit 1600 and the second wireless communication unit 2200 include an FIR filter, and in one embodiment of the present invention, it is preferable that the second antenna unit 2300 connected to the second wireless communication unit 2200 includes two antennas. According to the above embodiment, the master BMS can use either of the two antennas when receiving, and can use only one antenna when transmitting.

[0128] In other words, the master BMS 2000 must receive information about each battery cell from the first wireless communication unit 1600 of the 500 direct BMS 1000s without interference and check the battery status in real time. The core of a battery diagnostic system using wireless communication in electric vehicles is to ensure that such a wireless communication system can last for more than 10 years in various environments (e.g., cold, hot, with vibration). The following describes the wireless communication system of the present invention that supports one-to-many communication between the master BMS 2000 and multiple direct BMS 1000s, which was invented with these core requirements in mind.

[0129] Figure 13 is a schematic diagram showing the communication status of a battery cell diagnostic system in a common frequency channel and a communication frequency channel according to one embodiment of the present invention.

[0130] As shown in Figure 13, the master BMS 2000 sets a communication frequency channel for each of the direct BMS 1000s located inside the vehicle, and broadcasts broadcast data containing channel information for the communication frequency channel of each direct BMS 1000 on a common frequency channel at a predetermined interval. The direct BMS 1000s are configured to receive the data transmitted on the common frequency channel, and transmit and receive information about the battery cells to the master BMS 2000 on their own communication frequency channel included in the broadcast data received on the common frequency channel.

[0131] Furthermore, each of the aforementioned communication frequency channels and common frequency channels falls within the 900 MHz band, and the types of data transmitted and received through each channel are different. The aforementioned communication frequency channels include multiple narrowband channels divided into 200 kHz intervals within the 900 MHz band.

[0132] Specifically, in the aforementioned 1. Asynchronous Wireless Communication System and Method for Diagnosing Battery Cells, downlink frames and multiple uplink frames were set based on time-division information divided on a single frequency band. However, as shown in Figure 12, if the master BMS 2000 and multiple direct BMS 1000s communicate with each of the 500 direct BMS 1000s using the communication frame structure shown in Figure 9 within a single frequency band, the period of one communication frame (=0.8ms * 500 = 400ms) becomes excessively long. If the master BMS 2000 does not properly receive information transmitted by a particular direct BMS 1000, it will take 405ms to receive the information from that direct BMS 1000 again, resulting in very low data reliability.

[0133] To solve these problems, the present invention applies a wireless communication system to a battery cell diagnostic system and method of the present invention, which includes a communication frequency channel composed of a plurality of narrowband channels having a bandwidth of 200 kHz, and a common frequency channel independent of the communication frequency channel.

[0134] More specifically, as shown in Figure 13, the common frequency channel supports only downlink communication from the master BMS 2000 to multiple direct BMS 1000s, while the communication frequency channel supports both uplink and downlink communication from the direct BMS 1000 to the master BMS 2000.

[0135] Both the common frequency channel and the communication frequency channel are allocated to the 900MHz band and each has its own unique frequency band, so they do not interfere with each other. The common frequency channel is a channel that can always transmit to the master BMS2000 and can always receive from multiple direct BMS1000s.

[0136] On the other hand, the communication frequency channel consists of multiple narrowband channels, and each of the multiple direct BMS 1000s can wirelessly communicate data with the master BMS 2000 using its own narrowband channel set by the master BMS 2000. In other words, the master BMS 2000 broadcasts broadcast data containing channel information for the communication frequency channel of each of the multiple direct BMS 1000s at a predetermined period via downlink communication on the common frequency channel, and each of the multiple direct BMS 1000s that receives the broadcast data can transmit to the master BMS 2000 information about the battery cell connected to it using its own communication frequency channel based on the channel information contained in the received broadcast data. The common frequency channel and the communication frequency channel will be described in more detail below.

[0137] Figure 14 schematically shows the structure of a communication frame in a common frequency channel according to one embodiment of the present invention, and Figure 15 schematically shows the structure of a communication frame in a communication frequency channel according to one embodiment of the present invention.

[0138] As shown in Figures 14 and 15, the common frequency channel and the communication frequency channel correspond to channels through which data is wirelessly transmitted and received between a plurality of direct BMS 1000s and the master BMS 2000, and include a plurality of communication frames, each of which includes a subframe that includes a downlink frame broadcast by the master BMS 2000 to the plurality of direct BMS 1000s and a plurality of uplink frames transmitted by each of the plurality of direct BMS 1000s to the master BMS 2000, each uplink frame in the subframe being temporally divided, and the data received by the plurality of direct BMS 1000s through the downlink frame on the communication frequency channel includes identifier information for each direct BMS 1000 and time-division information of the uplink frame associated with the direct BMS 1000 having the identifier information, and each direct BMS 1000 transmits data for the battery cell connected to it to the master BMS 2000 through the uplink frame assigned to it, based on the time-division information and channel information of its own uplink frame included in the data received in the downlink frame.

[0139] Furthermore, the communication frame of the communication frequency channel includes multiple identical subframes, and each subframe is configured such that multiple uplink frames follow the downlink frame according to a predetermined rule. The data broadcast in the downlink frame includes request information for the target to be transmitted by each direct BMS 1000. Each direct BMS 1000 generates response information based on the request information contained in the data broadcast in the downlink frame, and transmits data including the response information to the master BMS 2000 using the time-division multiplexing information and channel information of its own uplink frame.

[0140] In general terms, Figures 14 and 15 show a communication system as one embodiment of the present invention, for the sake of explanation, in which the 903 MHz band is set as the common frequency channel and the 898.0 MHz to 902.8 MHz band is set as the communication frequency channel. However, the configuration of the frequencies assigned to the common frequency channel and the communication frequency channel is a configuration that can be modified according to the inventor's intent. That is, the common frequency channel can be set at either end of the limited 900 MHz band, but according to other embodiments of the present invention, the frequency band of the common frequency channel can correspond to any one band within the limited 900 MHz band.

[0141] Furthermore, although Figures 14 and 15 show the common frequency channel and the multiple communication frequency channels as communication channels having a bandwidth of 200 kHz, according to other embodiments of the present invention, the bandwidth of the common frequency channel can be modified in design according to the inventor's intent.

[0142] Furthermore, to aid in understanding the drawings, Figures 14 and 15 show that multiple narrowband channels are adjacent to each other. In practice, however, in the present invention, it is desirable that guard bands to prevent interference between channels be provided between consecutive channels.

[0143] Specifically, as shown in Figures 14 and 15, the common frequency channel and the communication frequency channel are divided into communication frames with a fixed period (100 ms in Figures 14 and 15), referring to the explanation given in Figures 9 to 11. Each communication frame consists of multiple subframes (four subframes in Figures 14 and 15). On the other hand, the subframes of the common frequency channel in Figure 14 differ from the subframes in Figures 9 to 11 in that they consist only of downlink frames.

[0144] More specifically, the common frequency channel is a channel through which the master BMS 2000 transmits information necessary for subsequent communications to the direct BMS 1000, and the broadcast data that the master BMS 2000 broadcasts to multiple direct BMS 1000s via the common frequency channel includes the identifier of each of the multiple direct BMS 1000s and the channel information corresponding to each of the identifiers.

[0145] For example, for direct BMS #1 to #25 (1000.1 to 1000.25), channel information #1, indicating communication on a communication frequency channel in the 898.0 MHz band, can be transmitted to the broadcast data along with the identifier information for each direct BMS #1 to #25 (1000.1 to 1000.25). Similarly, for direct BMS #26 to #50 (1000.26 to 1000.50), channel information #2, indicating communication on a communication frequency channel in the 898.2 MHz band, can be transmitted to the broadcast data along with the identifier information for each direct BMS #26 to #50 (1000.26 to 1000.50).

[0146] Furthermore, as shown in Figure 14, the present invention adopts a configuration that allows the same information to be transmitted repeatedly by repeatedly arranging the same downlink frame within a single subframe, thereby enabling a large number of direct BMS 1000s to stably receive broadcast data.

[0147] On the other hand, as shown in Figure 15, a subframe of a communication frequency channel includes a single downlink frame and multiple uplink frames. The master BMS 2000 broadcasts data through the downlink frame of the communication frequency channel, which includes the identifier information of each of the multiple direct BMS 1000s communicating on that channel, and the time-division multiplexing information of the uplink frame corresponding to that identifier information.

[0148] In other words, referring to the example above, the master BMS2000 broadcasts data via the downlink frame of the 898.0MHz band communication frequency channel, including the identifier information of each direct BMS#1~#25 (1000.1~1000.25) that has received channel information #1 indicating that it is communicating on the 898.0MHz band communication frequency channel, and the time-division multiplexing information of the uplink frame assigned to each of the direct BMS#1~#25 (1000.1~1000.25). Upon receiving this data, each direct BMS#1~#25 (1000.1~1000.25) can transmit information including voltage, current, temperature, etc., for each or all of the battery cells contained in each of the battery modules #1~#25 connected to it, based on the time-division multiplexing information of its own uplink frame.

[0149] Furthermore, the data broadcast by the master BMS2000 through the downlink frame of the communication frequency channel may further include request information for each receiving direct BMS1000 (for example, a command to perform cell balancing).

[0150] On the other hand, Figures 14 and 15 show a configuration in which the master BMS 2000 and the direct BMS 1000 simultaneously transmit and receive data through the common frequency channel and the communication frequency channel, respectively. However, preferably, while the direct BMS 1000 is receiving broadcast data transmitted by the master BMS 2000 through the common frequency channel, the direct BMS 1000 cannot receive or transmit data through the communication frequency channel. The direct BMS 1000 receives the broadcast data through the common frequency channel, and then receives and transmits data through the communication frequency channel.

[0151] On the other hand, conventional wireless communication technologies for battery diagnostics employ a frame error control function. More specifically, this involves modulating the transmitted signal using convolutional encoding during transmission and demodulating the received signal using Viterbi decoding during reception. Because such a configuration is included in each cell diagnostic sensor node semiconductor, it hinders the efficient use of space in the battery pack and results in high production costs.

[0152] The present invention, in order to solve the aforementioned problems, is characterized by adding an on / off function that is switched on / off depending on the radio wave environment to the frame error control configuration described above, and including a configuration that excludes the Viterbi decoding configuration. In other words, in a general radio wave environment, the aluminum shielding of the battery pack blocks radio wave interference sources, creating a radio wave clean environment, so by turning off the frame error control configuration, the time required for transmission and reception can be shortened and the efficiency of communication can be improved.

[0153] Furthermore, by arranging multiple identical subframes to be repeated within a single communication frame, it is possible to design a frame error control configuration that guarantees communication reliability without the Viterbi decoding configuration, thereby simplifying the structure of the sensor node. In other words, the improved frame error control configuration of the present invention makes it possible to reduce the size of the dozens or more cell diagnostic sensor node semiconductors installed in each vehicle, resulting in a reduction in production costs.

[0154] On the other hand, in a preferred embodiment, the data rate on the common frequency channel and the communication frequency channel is designed to be 2 Mbps or more, and the SNR (Signal-to-Noise Ratio) of the communication system of the present invention is 10 -6 It is designed as follows. Furthermore, the receiving sensitivity of the communication frequency channel is preferably designed to be -85 dBM, and the PAPR (Peak to Average Power Ratio) is preferably designed to be 3 to 5.

[0155] Figure 16 schematically shows data broadcast on a common frequency channel according to one embodiment of the present invention, and Figure 17 schematically shows data broadcast on a communication frequency channel according to one embodiment of the present invention.

[0156] In general terms, Figures 16 and 17 show the information transmitted to the direct BMS 1000 via the downlink frame of the common frequency channel and the information transmitted to the direct BMS 1000 via the downlink frame of the communication frequency channel.

[0157] Specifically, as shown in Figure 16, the master BMS 2000 broadcasts information via a common frequency channel that includes identifier information for the direct BMS 1000 and channel information related to the communication frequency channel used to communicate with the corresponding direct BMS 1000. Initially, the channel information is pre-configured for each direct BMS 1000, but the master BMS 2000 can maintain a stable communication state by continuously analyzing the communication status with the direct BMS 1000 and actively changing the channel information.

[0158] As shown in Figure 17, the master BMS 2000 broadcasts data via the downlink frame of the communication frequency channel, including identifier information of the direct BMS 1000, time-division information of the uplink frame related to the time-slot communicating with the direct BMS 1000, and request information regarding commands or controls for the direct BMS 1000. Examples of such request information include commands to request the voltage value of a battery cell connected to the direct BMS 1000, commands to perform cell balancing because the voltage value of the battery cell is irregular beyond a predetermined range, and commands to reduce the battery input / output because the temperature of the direct BMS 1000 is very high.

[0159] Furthermore, although the time-division information is initially set separately for each direct BMS 1000, the master BMS 2000 can maintain a stable communication state by continuously analyzing the communication status with the direct BMS 1000 and actively changing the time-division information.

[0160] As described above, the master BMS2000 transmits data including channel information and time-division multiplexing information for communication with the direct BMS1000 via two independently operated downlink frames before the uplink frame, thereby synchronizing communication and ensuring the reliability of data transmission and reception at an early stage.

[0161] Figure 18 is a schematic diagram illustrating the execution steps of the error correction configuration according to one embodiment of the present invention.

[0162] As shown in Figure 18, if the master BMS 2000 detects a communication error during the communication process with multiple direct BMS 1000s, the master BMS 2000 can modify the time-division information of the direct BMS 1000 corresponding to the uplink frame in which the communication error occurred, and then broadcast the data including the modified time-division information through the communication frequency channel.

[0163] Furthermore, if the master BMS 2000 detects a communication error during communication with multiple direct BMS 1000s, the master BMS 2000 can change the channel information of the direct BMS 1000 corresponding to the uplink frame in which the communication error occurred, and then broadcast the broadcast data including the changed channel information through a common frequency channel.

[0164] Specifically, as shown in Figure 10, if the master BMS 2000 fails to successfully receive data from a particular direct BMS 1000 through a specific uplink frame, it can determine the information to be transmitted from that direct BMS 1000 based on data received from the same direct BMS 1000 through other uplink frames.

[0165] However, if such communication errors occur more than a predetermined number of times or over a predetermined period of time, the present invention is characterized by actively resolving the communication errors using the algorithm shown in Figure 18 to ensure communication stability.

[0166] More specifically, if the master BMS 2000 detects a communication error with a specific direct BMS 1000 a predetermined number of times or for a predetermined period of time (S100), the master BMS 2000 changes the time division information to be transmitted to the direct BMS 1000 (S110), and then broadcasts the changed time division information through the downlink frame of the relevant communication frequency channel. Upon receiving the changed time division information, the direct BMS 1000 changes the time division information of its uplink frame, and thereafter, if it communicates with the master BMS 2000 without communication errors for a predetermined first time period in the time slot changed by the changed time division information (S120), the direct BMS 1000 and the master BMS 2000 communicate through the uplink frame based on the changed time division information.

[0167] On the other hand, if a communication error with the direct BMS 1000 is detected in the changed time slot during the predetermined first time period (S120), the master BMS 2000 changes the channel information to be transmitted to the direct BMS 1000 (S130) and then broadcasts the changed channel information through the common frequency channel. Upon receiving the changed channel information, the direct BMS 1000 changes its own communication frequency channel, and thereafter, if it communicates normally with the master BMS 2000 without communication errors for a predetermined second time period on the changed communication frequency channel (S140), the direct BMS 1000 and the master BMS 2000 transmit and receive data on the corresponding communication frequency channel.

[0168] If the communication error persists after step S130, the master BMS2000 can generate a fault alarm and provide it to the user, which can then take additional action.

[0169] On the other hand, in another embodiment of the present invention, step S130 may be performed prior to step S110. That is, if a communication error is detected, the master BMS 2000 can resolve the communication error by changing the channel information of the corresponding direct BMS 1000 and then changing the time division information.

[0170] Although the embodiments have been described above with reference to limited embodiments and drawings, various modifications and variations can be made from the above description by a person with ordinary skill in the art. For example, the described technique may be performed in a procedure different from the described method, and / or the components of the described system, structure, apparatus, circuit, etc. may be combined or combined in a manner different from the described method, or replaced or substituted with other components or equivalents, and the appropriate results may be achieved. Therefore, other realizations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. A diagnostic system for battery cells located inside a vehicle, Multiple direct BMSs located inside the vehicle and electrically connected to multiple battery cells included in the battery module, It includes a master BMS located inside the vehicle that communicates wirelessly with the direct BMS, The aforementioned direct BMS is A battery cell connection unit having ports that make direct physical and electrical contact with the exposed electrodes of each of the plurality of battery cells, A voltage measuring unit electrically connected to the aforementioned battery cell connection section and measuring the voltage of each battery cell in a circuit configuration, A current measuring unit electrically connected to the aforementioned battery cell connection section and measuring the current of the battery cell or battery module in a circuit configuration, MCU and, It includes a first wireless communication unit connected to the MCU and performing wireless communication with the master BMS, The master BMS sets a communication frequency channel for each of the direct BMSs located within the vehicle, and broadcasts broadcast data containing channel information related to the communication frequency channel for each direct BMS at a predetermined interval on a common frequency channel. The direct BMS is configured to receive data transmitted to a common frequency channel, and the battery cell diagnostic system is characterized by transmitting and receiving information about the battery cell with the master BMS using its own communication frequency channel included in the broadcast data received on the common frequency channel.

2. The positive and negative terminals of the battery cell are in direct contact with the port provided in the battery cell connection section. The battery cell diagnostic system according to claim 1, characterized in that the voltage measuring unit measures the voltage for each of the battery cells.

3. The aforementioned communication frequency channel is This corresponds to a channel in which data is transmitted wirelessly between multiple direct BMSs and the master BMS, and includes multiple communication frames. The communication frame includes a subframe which includes a downlink frame broadcast by the master BMS on the plurality of direct BMSs and a plurality of uplink frames which each of the plurality of direct BMSs transmits on the master BMS. The battery cell diagnostic system according to claim 1, characterized in that each uplink frame in the subframe is divided in time.

4. The data that multiple direct BMSs receive through the downlink frame on the communication frequency channel is: The identifier information for each direct BMS, This includes time-division multiplexing information of the uplink frame relating to the direct BMS having the relevant identifier information, The battery cell diagnostic system according to claim 3, characterized in that each direct BMS transmits data for the battery cell connected to it to the master BMS via the uplink frame assigned to it, based on the time-division information and channel information of its uplink frame contained in the data received in the downlink frame.

5. The battery cell diagnostic system according to claim 1, characterized in that each of the aforementioned communication frequency channel and common frequency channel corresponds to the 900 MHz band, and the types of data transmitted and received through each channel are different.

6. The battery cell diagnostic system according to claim 1, characterized in that the communication frequency channel includes a plurality of narrowband channels divided at 200 kHz intervals in a 900 MHz band.

7. The communication frame of the aforementioned communication frequency channel contains multiple identical subframes. The aforementioned subframe is In terms of time, multiple uplink frames are configured according to a predetermined rule after the downlink frame. The data broadcast in the aforementioned downlink frame includes request information for the target transmitted from each direct BMS, The battery cell diagnostic system according to claim 1, characterized in that each direct BMS generates response information in response to request information contained in the data broadcast in the downlink frame, and transmits data including the response information to the master BMS using the time-division information and channel information of its own uplink frame.

8. If the master BMS detects a communication error during the communication process with multiple direct BMSs, The battery cell diagnostic system according to claim 7, characterized in that the master BMS modifies the time-division information of the direct BMS corresponding to the uplink frame in which a communication error occurred, and then broadcasts data including the modified time-division information through a communication frequency channel.

9. If the master BMS detects a communication error during the communication process with multiple direct BMSs, The battery cell diagnostic system according to claim 7, characterized in that the master BMS changes the channel information of the direct BMS corresponding to the uplink frame in which a communication error occurred, and then broadcasts broadcast data including the changed channel information through a common frequency channel.

10. The battery cell diagnostic system according to claim 1, characterized in that the period of communication frames transmitted and received by the direct BMS and the master BMS or the time interval between consecutive data frames is varied according to the driving conditions of the vehicle on which the battery module is installed.

11. A method for diagnosing battery cells performed by a battery cell diagnostic system located inside a vehicle, The diagnostic system for the aforementioned battery cell is: Multiple direct BMSs located inside the vehicle and electrically connected to multiple battery cells included in the battery module, It includes a master BMS located inside the vehicle that communicates wirelessly with the direct BMS, The method for diagnosing the aforementioned battery cell is: In the battery cell connection section of the direct BMS, the steps include: the port included in the battery cell connection section and the exposed electrodes of each of the plurality of battery cells being in direct physical and electrical contact; In the voltage measurement section of the direct BMS, the voltage of each battery cell is measured in the following steps: In the current measurement section of the direct BMS, the steps include measuring the current of a battery cell or battery module, The first wireless communication unit of the direct BMS includes the step of performing wireless communication with the master BMS, The first wireless communication unit is connected to the MCU of the direct BMS, The master BMS sets a communication frequency channel for each of the direct BMSs located within the vehicle, and broadcasts broadcast data containing channel information related to the communication frequency channel for each direct BMS at a predetermined interval on a common frequency channel. The direct BMS is configured to receive data transmitted to a common frequency channel, and the battery cell diagnostic system is characterized by transmitting and receiving information about the battery cell with the master BMS using its own communication frequency channel included in the broadcast data received on the common frequency channel.

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