Wireless communication method and battery system providing the same

Abstract

The present invention relates to a method for wireless communication between a plurality of battery management systems (BMS) and a battery system providing the method. The battery system according to the present invention comprises at least one battery pack including a battery module and a slave BMS that manages the battery module, wherein the battery system comprises a communication unit of the slave BMS, a capacitor connected between the communication unit and a first ground, an inductor connected between a contact between the first ground and the capacitor and a second ground, and a control unit that transmits an alternating current signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with the outside.

Description

Technology Field

[0001] The present invention relates to a wireless communication method between a plurality of battery management systems (BMS) and a battery system providing the method. Background Technology

[0002] A battery system applied to electric vehicles, etc., may include multiple battery packs, each comprising a battery module and a slave Battery Management System (SMS) that manages the battery modules. Additionally, the battery system may further include a master Battery Management System (Master BMS) that communicates with the vehicle system and manages multiple battery packs.

[0003] Recently, research and development on wireless communication between a master BMS and multiple slave BMSs is increasing in order to solve problems such as poor quality of electrical wiring and frequent maintenance issues related to wire cables and connectors, and to increase the driving range by reducing the weight of electric vehicles. The problem to be solved

[0004] The present invention provides a wireless communication method capable of wireless communication between a plurality of Battery Management Systems (BMS) without adding separate components for wireless communication, and a battery system providing the method.

[0005] The present invention provides a wireless communication method capable of wireless communication between a plurality of Battery Management Systems (BMS) in various Industrial Scientific and Medical (ISM) bands, and a battery system providing the method. means of solving the problem

[0006] A battery system according to one feature of the present invention comprises at least one battery pack including a battery module and a slave BMS (Battery Management System) that manages the battery module, a communication unit of the slave BMS, a capacitor connected between the communication unit and a first ground, an inductor connected between a contact between the first ground and the capacitor and a second ground, and a control unit that transmits an alternating current signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with the outside.

[0007] The above inductor may be located between the battery module and the slave BMS.

[0008] The length between the inductor and the first ground can correspond to 1 / 4 of the wavelength of the alternating current signal.

[0009] The first ground may be the signal ground of the slave BMS, and the second ground may be the chassis ground of the battery module.

[0010] The battery module may further include a monitoring unit electrically connected to each of a plurality of battery cells included in the battery module and collecting battery data including at least one of the current, voltage, and temperature of each of the plurality of battery cells.

[0011] The control unit can transmit a DC signal to the communication unit in a monitoring mode in which the monitoring unit collects the battery data.

[0012] The battery system may further include a master BMS that manages at least one slave BMS by wirelessly communicating with the communication unit.

[0013] The control unit can transmit the collected battery data to the master BMS through the communication unit in the antenna mode.

[0014] A wireless communication method according to another feature of the present invention is a method for wirelessly communicating in a battery system comprising a communication unit of a slave BMS (Battery Management System) that manages a battery module, a capacitor connected between the communication unit and a first ground, and an inductor connected between a contact between the first ground and the capacitor and a second ground, and includes the step of transmitting an alternating current signal having a predetermined frequency to the communication unit so that the slave BMS communicates with the outside.

[0015] The above inductor may be located between the battery module and the slave BMS.

[0016] The length between the inductor and the first ground can correspond to 1 / 4 of the wavelength of the alternating current signal.

[0017] The first ground above may be the signal ground of the slave BMS, and the second ground may be the chassis ground of the battery module.

[0018] The battery system may further include a monitoring unit electrically connected to each of a plurality of battery cells included in the battery module and collecting battery data including at least one of the current, voltage, and temperature of each of the plurality of battery cells.

[0019] The above wireless communication method further includes a step in which the monitoring unit collects the battery data prior to the step of communicating with the outside, and the step of collecting the battery data may include a step of transmitting a DC signal to the communication unit.

[0020] The step of communicating with the outside may include the step of transmitting the collected battery data to a master BMS managing the slave BMS through the communication unit. Effects of the invention

[0021] The present invention can reduce the size of the BMS PCB because there is no need to add components for wireless communication (e.g., antennas, etc.) inside the BMS PCB (Printed Circuit Board).

[0022] The present invention can reduce the purchase cost of components for wireless communication (e.g., antennas, etc.).

[0023] Since the present invention does not require changing the BMS PCB according to the frequency band, a commonization design of the BMS PCB is possible. Brief explanation of the drawing

[0024] FIG. 1 is a block diagram illustrating a battery system according to one embodiment. Figure 2 is a block diagram illustrating the battery pack of Figure 1 in detail. FIG. 3 is a block diagram that explains in detail when the battery pack of FIG. 1 operates in monitoring mode. FIG. 4 is a block diagram that explains in detail when the battery pack of FIG. 1 operates in antenna mode. Figure 5 is a block diagram illustrating the antenna of Figure 4 in detail. FIG. 6 is a flowchart illustrating a wireless communication method according to one embodiment. Specific details for implementing the invention

[0025] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components are assigned identical or similar reference numerals, and redundant descriptions thereof will be omitted. The suffixes "module" and / or "part" for components used in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not have distinct meanings or roles in themselves. Furthermore, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0026] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0027] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0028] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0030] FIG. 1 is a block diagram illustrating a battery system according to one embodiment, and FIG. 2 is a block diagram illustrating the battery pack of FIG. 1 in detail.

[0031] Referring to FIG. 1, the battery system (1) includes a battery (10) and a master BMS (Master BMS, Battery Management System, hereinafter referred to as Master BMS) (20).

[0032] The battery (10) includes at least one battery pack. Although a plurality of battery packs (10_1-10_n) are shown in FIG. 1, the battery (10) is not limited thereto and may include one battery pack (10_1).

[0033] Hereinafter, when referring to a specific battery pack among a plurality of battery packs (10_1-10_n), the reference numeral “10_j” is used, and the battery module and slave BMS included in the battery pack (10_j) are each referred to as the reference numerals “100j” and “200j”. Additionally, the capacitor, inductor, contact, and antenna included in the battery pack (10_j) to be described below are each referred to as the reference numerals “Cj”, “Lj”, “Nj”, and “200_Aj”.

[0034] The battery pack (10_j) includes a battery module (100j) and a slave BMS (200j).

[0035] A battery module (100j) may include a plurality of battery cells connected in series and / or parallel. In some embodiments, the battery cells may be rechargeable secondary batteries. FIGS. 1 and 2 illustrate a battery module (100j) comprising three battery cells (Cell1, Cell2, Cell3) connected in series, but are not limited thereto. The battery module (100j) may include an varying number of battery cells.

[0036] The slave BMS (200j) can collect battery data for the battery module (100j) and transmit the collected battery data to the master BMS (20) via wireless communication. At this time, the battery data may include at least one of the cell voltage, cell current, and cell temperature of each of the plurality of battery cells (Cell1, Cell2, Cell3). Additionally, the battery data may include at least one of the module voltage, which is the voltage across the battery module (100j), and the module current, which is the current flowing through the battery module (100j).

[0037] Referring to FIG. 2, the slave BMS (200j) may include a monitoring unit (210), a communication unit (220), a control unit (230), a capacitor (Cj), and an inductor (Lj).

[0038] The monitoring unit (210) is electrically connected to the battery module (100j) and collects battery data. For example, the monitoring unit (210) may be composed of an Integrated Circuit (IC) capable of collecting battery data, such as an Application Specific IC (ASIC) or a Battery Monitoring IC (BMIC).

[0039] Referring to FIG. 2, for example, a monitoring unit (210) is electrically connected to the positive and negative electrodes of each of a plurality of battery cells (Cell1, Cell2, Cell3) to measure the cell voltage of each of the plurality of battery cells (Cell1, Cell2, Cell3). In another example, the monitoring unit (210) may receive information regarding the cell current and cell temperature measured by a current sensor (not shown) and a temperature sensor (not shown), respectively. In yet another example, the monitoring unit (210) may measure the cell voltage of each of the plurality of battery cells (Cell1, Cell2, Cell3) at a predetermined period during a rest period in which charging and discharging do not occur, and calculate the cell current based on the measured cell voltage. The monitoring unit (210) may collect battery data at predetermined periods or in real time and transmit the collected battery data to the control unit (230).

[0040] The communication unit (220) may be an analog signal processing device that processes data requiring transmission. For example, the communication unit (220) may be composed of an RFIC (Radio Frequency IC), but is not limited thereto.

[0041] According to an embodiment, the control unit (230) may convert a digital signal into an analog signal (AC signal) and transmit it to the communication unit (220). Then, the communication unit (220) processes the analog signal by amplifying and filtering it, and transmits the processed analog signal to the antenna. The antenna may convert the processed analog signal into an electromagnetic wave and transmit the electromagnetic wave into the air. According to an embodiment, the antenna may be an antenna generated in antenna mode, and a detailed description is provided below in conjunction with FIGS. 4 and 5.

[0042] The control unit (230) can control the overall operation of the slave BMS (200j). For example, it can control the monitoring unit (210) to collect battery data and control the communication unit (220) to transmit the collected battery data to the master BMS (20).

[0043] The capacitor (Cj) can be connected between the communication unit (220) and the first ground (GND1). At this time, the first ground (GND1) may be a signal ground located in the slave BMS (200j), but is not limited thereto. For example, the first ground (GND1) may be implemented as an earth ground or a chassis ground.

[0044] The inductor (Lj) can be connected between the contact (Nj) between the first ground (GND1) and the capacitor (Cj) and the second ground (GND2). At this time, the second ground (GND2) may be a chassis ground located in the battery module (100j), but is not limited thereto. For example, the second ground (GND2) may be implemented as an earth ground or a signal ground.

[0045] According to an embodiment, with reference to FIG. 2, the inductor (Lj) may be located in the external space between the battery module (100j) and the slave BMS (200j). Specifically, one end of the inductor (Lj) connected to the contact (Nj) may be located outside the housing of the slave BMS (200j).

[0046] The master BMS (20) communicates with the upper control unit (2) to receive commands and information, and can manage and control the slave BMS (200j) included in at least one battery pack (10_j) according to the received commands. At this time, the upper control unit (2) may be the control unit of the upper system (e.g., automobile, ESS system, etc.) on which the battery system (1) is installed.

[0047] Referring again to FIG. 1, according to an embodiment, the master BMS (20) can wirelessly communicate with each of the plurality of slave BMSs (2001-200N) to transmit various control signals or receive battery data. The external device shown in FIG. 1 may be a charger in a charging mode for charging the battery (10), and a load (e.g., a motor, etc.) in a discharging mode for discharging the battery (10).

[0048] The slave BMS (200j) according to the embodiment can communicate wirelessly with the master BMS (20) without including a separate antenna device. This will be explained in detail below with reference to FIGS. 4 and FIGS. 5.

[0050] FIG. 3 is a block diagram illustrating in detail when the battery pack of FIG. 1 operates in monitoring mode, FIG. 4 is a block diagram illustrating in detail when the battery pack of FIG. 1 operates in antenna mode, and FIG. 5 is a block diagram illustrating in detail the antenna of FIG. 4.

[0051] According to an embodiment, the battery pack (10_j) can operate in a monitoring mode for collecting battery data and an antenna mode for communicating with the outside. Hereinafter, FIG. 3 describes the structure of the battery pack (10_j) in monitoring mode in detail, and FIG. 4 and FIG. 5 describe the structure of the battery pack (10_j) in antenna mode in detail.

[0052] Referring to FIG. 3, in monitoring mode, the control unit (230) can control the communication unit (220) to transmit a DC signal to the capacitor (Cj).

[0053] When a direct current (DC) signal is applied to a capacitor (Cj), a circuit as shown in FIG. 3 can be formed according to the electrical characteristics of the capacitor (Cj) that are opened by the DC signal. That is, one end of the inductor (Lj) can be connected to the first ground (GND1), and the other end of the inductor (Lj) can be connected to the second ground (GND2). At this time, external noise can be removed by the inductor (Lj).

[0054] Referring to FIG. 4, in antenna mode, the control unit (230) can control the communication unit (220) to transmit an alternating current signal (AC Signal) having a predetermined frequency to the capacitor (Cj).

[0055] When an alternating current (AC) signal is applied to a capacitor (Cj), a circuit as shown in FIG. 4 can be formed according to the electrical characteristics of an inductor (Lj) that is open to the alternating current (AC) signal. Specifically, a transmission line (indicated in bold) connecting a first terminal connected to the capacitor (Cj), a second terminal connected to the first ground (GND1), and a third terminal adjacent to the inductor (Lj) can perform the function of an inverted-F antenna. That is, in an antenna mode communicating with an external source (e.g., a master BMS), an antenna (Aj) corresponding to an inverted-F antenna structure can be formed in the slave BMS (200j).

[0056] An inverted F antenna is an antenna created to improve the impedance matching of an inverted-L antenna. In this case, the inverted-L antenna may be an antenna created by bending about 80% of the upper length of a monopole antenna horizontally to reduce its height.

[0057] Referring to FIG. 4, for example, the antenna (200_Aj) can convert an alternating current signal input through the communication unit (220) into an electromagnetic wave and transmit the converted electromagnetic wave into the air. As another example, the antenna (Aj) can receive the electromagnetic wave, convert the received electromagnetic wave into an alternating current signal, and transmit the converted alternating current signal to the communication unit (220).

[0058] Referring to FIG. 5, according to an embodiment, the antenna (200_Aj) can resonate at a frequency having a wavelength (λ) that is four times the antenna length (AL). Specifically, the inverse F antenna can be configured with an antenna length (AL=λ / 4) corresponding to one-fourth of the wavelength (λ) of the signal to be transmitted or received. At this time, the antenna length (AL) can correspond to the length between the inductor (Lj) and the first ground (GND1).

[0059] For example, to transmit and receive a signal corresponding to a frequency of 2.45 GHz, the antenna length (AL) may be configured to be 30.61 mm. As another example, to transmit and receive a signal corresponding to a frequency of 915 MHz, the antenna length (AL) may be configured to be 81.97 mm.

[0060] According to an embodiment, the antenna length (AL) can be determined based on the position (mounting distance) of the inductor (Lj). That is, by simply changing the position where the inductor (Lj) is mounted, the slave BMS (200j) can wirelessly communicate with the master BMS (20) in various ISM (Industrial Scientific and Medical) frequency bands.

[0062] FIG. 6 is a flowchart illustrating a wireless communication method according to one embodiment.

[0063] Hereinafter, with reference to FIGS. 1 to 6, a wireless communication method and a battery system providing the method will be described.

[0064] Referring to FIG. 6, first, the monitoring unit (210) collects battery data (S100).

[0065] The monitoring unit (210) can collect battery data at predetermined intervals or in real time and transmit the collected battery data to the control unit (230). At this time, the battery data may include at least one of the cell voltage, cell current, and cell temperature of each of the plurality of battery cells (Cell1, Cell2, Cell3). Additionally, the battery data may include at least one of the module voltage, which is the voltage across the battery module (100j), and the module current, which is the current flowing through the battery module (100j).

[0066] In step S100, the control unit (230) can control the communication unit (220) to transmit a DC signal to the capacitor (Cj). Specifically, in the monitoring mode step where the monitoring unit (210) collects battery data, when a DC signal is applied to the capacitor (Cj), a circuit as shown in FIG. 3 is formed according to the electrical characteristics of the capacitor (Cj) that is opened by the DC signal. That is, both ends are connected to the first ground (GND1) and the second ground (GND2), respectively, and an inductor (Lj) can be located between the first ground (GND1) and the second ground (GND2). At this time, external noise can be removed by the inductor (Lj). Then, the monitoring unit (210) can collect battery data with minimal influence from external noise.

[0067] Next, the control unit (230) transmits the battery data collected through the communication unit (220) to the master BMS (20) (S200).

[0068] According to one embodiment, the control unit (230) can transmit battery data to the BMS (20) through the communication unit (220). According to another embodiment, the control unit (230) can transmit various information or receive control signals by wirelessly communicating with the outside through the communication unit (220). At this time, the outside may be the master BMS (20), but is not limited thereto, and may include various devices located outside the slave BMS (200j).

[0069] In step S200, the control unit (230) can control the communication unit (220) to transmit an alternating current signal having a predetermined frequency to the capacitor (Cj). Specifically, when an alternating current (AC) signal is applied to the capacitor (Cj), a circuit as shown in FIG. 4 is formed according to the electrical characteristics of the inductor (Lj) that is open in the alternating current signal. Specifically, a transmission line (part shown in bold) connecting the first terminal connected to the capacitor (Cj), the second terminal connected to the first ground (GND1), and the third terminal adjacent to the inductor (Lj) can perform the function of an inverted-F antenna. That is, in the antenna mode stage for communicating with the outside, an antenna (200_Aj) corresponding to the inverted-F antenna structure can be formed in the slave BMS (200j).

[0070] An inverted F antenna is an antenna created to improve the impedance matching of an inverted-L antenna. In this case, the inverted-L antenna may be an antenna created by bending about 80% of the upper length of a monopole antenna horizontally to reduce its height.

[0071] Referring to FIG. 5, for example, the antenna (200_Aj) can convert an alternating current signal input through the communication unit (220) into an electromagnetic wave and transmit the converted electromagnetic wave into the air. As another example, the antenna (200_Aj) can receive the electromagnetic wave, convert the received electromagnetic wave into an alternating current signal, and transmit the converted alternating current signal to the communication unit (220).

[0072] Referring again to FIG. 4, according to an embodiment, the antenna (200_Aj) can resonate at a frequency having a wavelength (λ) that is four times the antenna length (AL). Specifically, the inverted F antenna can be configured with an antenna length (AL=λ / 4) corresponding to 1 / 4 of the wavelength (λ) of the signal to be transmitted or received. At this time, the antenna length (AL) can correspond to the length between the inductor (Lj) and the first ground (GND1).

[0073] For example, to transmit and receive a signal corresponding to a frequency of 2.45 GHz, the antenna length (AL) may be configured to be 30.61 mm. As another example, to transmit and receive a signal corresponding to a frequency of 915 MHz, the antenna length (AL) may be configured to be 81.97 mm.

[0074] According to an embodiment, the antenna length (AL) can be determined based on the position (mounting distance) of the inductor (Lj). That is, by simply changing the position where the inductor (Lj) is mounted, the slave BMS (200j) can wirelessly communicate with the master BMS (20) in various ISM (Industrial Scientific and Medical) frequency bands.

[0075] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modified and improved forms by those skilled in the art to which the present invention pertains also fall within the scope of the present invention.

Claims

Claim 1 A battery system comprising at least one battery pack including a battery module and a slave BMS (Battery Management System) that manages the battery module, wherein the battery system comprises a communication unit of the slave BMS, a capacitor connected between the communication unit and a first ground, an inductor connected between a contact between the first ground and the capacitor and a second ground, and a control unit that transmits an alternating current signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with the outside. Claim 2 In claim 1, the battery system, wherein the inductor is located between the battery module and the slave BMS. Claim 3 A battery system according to paragraph 2, wherein the length between the inductor and the first ground corresponds to 1 / 4 of the wavelength of the alternating current signal. Claim 4 A battery system according to paragraph 3, wherein the first ground is the signal ground of the slave BMS and the second ground is the chassis ground of the battery module. Claim 5 A battery system according to claim 1, further comprising a monitoring unit electrically connected to each of a plurality of battery cells included in the battery module and collecting battery data including at least one of the current, voltage, and temperature of each of the plurality of battery cells. Claim 6 In paragraph 5, the control unit transmits a DC signal to the communication unit in a monitoring mode in which the monitoring unit collects the battery data, in a battery system. Claim 7 A battery system according to claim 6, further comprising a master BMS that manages at least one slave BMS by wirelessly communicating with the communication unit. Claim 8 In claim 7, the battery system wherein the control unit transmits the collected battery data to the master BMS through the communication unit in the antenna mode. Claim 9 A wireless communication method in a battery system comprising a communication unit of a slave BMS (Battery Management System) that manages a battery module, a capacitor connected between the communication unit and a first ground, and an inductor connected between a contact between the first ground and the capacitor and a second ground, the wireless communication method comprising the step of transmitting an alternating current signal having a predetermined frequency to the communication unit so that the slave BMS communicates with the outside. Claim 10 In claim 9, the wireless communication method wherein the inductor is located between the battery module and the slave BMS. Claim 11 A wireless communication method according to claim 10, wherein the length between the inductor and the first ground corresponds to 1 / 4 of the wavelength of the alternating current signal. Claim 12 A wireless communication method according to claim 11, wherein the first ground is the signal ground of the slave BMS and the second ground is the chassis ground of the battery module. Claim 13 A wireless communication method according to claim 9, wherein the battery system further comprises a monitoring unit electrically connected to each of a plurality of battery cells included in the battery module and collecting battery data including at least one of the current, voltage, and temperature of each of the plurality of battery cells. Claim 14 A wireless communication method according to claim 13, wherein prior to the step of communicating with the outside, the monitoring unit further includes the step of collecting the battery data, and the step of collecting the battery data includes the step of transmitting a direct current signal to the communication unit. Claim 15 A wireless communication method according to claim 14, wherein the step of communicating with the outside includes the step of transmitting the collected battery data to a master BMS managing the slave BMS through the communication unit.

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