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 same. The battery system according to the present invention includes at least one battery pack including a battery module and a slave BMS (Battery Management System) that manages the battery module, and includes a communication unit of the slave BMS, a capacitor connected between the communication unit and a first ground, an inductor connected between a junction between the first ground and the capacitor and a second ground, and a control unit that transmits an AC signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with the outside.

Description

[Technical Field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0083730 dated July 7, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a wireless communication method between a plurality of battery management systems (BMS) and a battery system that provides the method. [Background technology]

[0003] A battery system applied to an electric vehicle or the like may include a plurality of battery packs each including a battery module and a slave battery management system (BMS) that manages the battery modules. The battery system may also include a master battery management system (BMS) that communicates with the vehicle system and manages the plurality of battery packs.

[0004] Recently, there has been an increase in research and development into methods for wirelessly communicating between a master BMS and multiple slave BMSs in order to solve problems such as poor quality electrical wiring and frequent maintenance and repair issues associated with wire cables and connectors, and to reduce the weight of electric vehicles and increase their mileage. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a wireless communication method that enables wireless communication between a plurality of BMSs (Battery Management Systems) without adding a separate component for wireless communication, and a battery system that provides the method.

[0006] The present invention provides a wireless communication method that enables wireless communication between a plurality of Battery Management Systems (BMS) in various ISM (Industrial Scientific and Medical) bands, and a battery system that provides the method. [Means for solving the problem]

[0007] According to one aspect of the present invention, a battery system includes at least one battery pack including a battery module and a slave BMS (Battery Management System) that manages the battery module, and includes: a communication unit of the slave BMS; a capacitor connected between the communication unit and a first ground; an inductor connected between a junction between the first ground and the capacitor and a second ground; and a control unit that transmits an AC signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with the outside.

[0008] The inductor may be disposed between the battery module and the slave BMS.

[0009] The length between the inductor and the first ground may correspond to 1 / 4 of the wavelength of the AC signal.

[0010] The first ground may be a signal ground of the slave BMS, and the second ground may be a chassis ground of the battery module.

[0011] 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 configured to collect battery data including at least one of a current, a voltage, and a temperature of each of the plurality of battery cells.

[0012] The control unit may transmit a DC signal to the communication unit in a monitoring mode in which the monitoring unit collects the battery data.

[0013] The battery system may further include a master BMS that wirelessly communicates with the communication unit and manages the at least one slave BMS.

[0014] The control unit may transmit the collected battery data to the master BMS through the communication unit in the antenna mode.

[0015] According to another aspect of the present invention, a wireless communication method is a method for wireless communication in a battery system including 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 junction between the first ground and the capacitor and a second ground, the method including transmitting an AC signal having a predetermined frequency to the communication unit so that the slave BMS communicates with an external device.

[0016] The inductor may be disposed between the battery module and the slave BMS.

[0017] The length between the inductor and the first ground may correspond to 1 / 4 of the wavelength of the AC signal.

[0018] The first ground may be a signal ground of the slave BMS, and the second ground may be a chassis ground of the battery module.

[0019] 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 configured to collect battery data including at least one of a current, a voltage, and a temperature of each of the plurality of battery cells.

[0020] The wireless communication method may further include a step of the monitoring unit collecting the battery data before 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.

[0021] The communicating with the outside may include transmitting the collected battery data to a master BMS that manages the slave BMS through the communication unit. [Effects of the Invention]

[0022] In the embodiment of the present invention, it is not necessary to add components for wireless communication (such as an antenna) inside a BMS (Printed Circuit Board) PCB, so the size of the BMS PCB can be reduced.

[0023] Embodiments of the present invention can reduce the cost of purchasing components (eg, antennas) for wireless communication.

[0024] In the embodiment of the present invention, the BMS PCB does not need to be changed depending on the frequency band, and therefore a commonization design of the BMS PCB is possible. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a block diagram illustrating a battery system according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating the battery pack of FIG. 1 in more detail. [Figure 3]FIG. 2 is a block diagram illustrating in detail when the battery pack of FIG. 1 operates in a monitoring mode. [Figure 4] FIG. 2 is a block diagram illustrating in detail when the battery pack of FIG. 1 operates in antenna mode. [Figure 5] FIG. 5 is a block diagram illustrating the antenna of FIG. 4 in more detail. [Figure 6] 1 is a flowchart illustrating a wireless communication method according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, the embodiments disclosed herein will be described in detail with reference to the accompanying drawings. Identical or similar components will be designated by the same or similar drawing numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and / or "section" for components used in the following description are assigned or used interchangeably solely for the convenience of writing the specification, and do not have any distinct meanings or roles. Furthermore, in describing the embodiments disclosed herein, if it is determined that a detailed description of related known technology may obscure the gist of the embodiments disclosed herein, such a detailed description will be omitted. Furthermore, the accompanying drawings are merely intended to facilitate understanding of the embodiments disclosed herein, and the accompanying drawings should not be construed as limiting the technical concept disclosed herein, and should be understood to include all modifications, equivalents, or alternatives within the concept and technical scope of the present invention.

[0027] Terms including ordinal numbers such as "first," "second," etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0028] When a component is said to be "coupled" or "connected" to another component, it should be understood that it may be directly coupled or connected to the other component, but that there may be other components in between. Conversely, when a component is said to be "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0029] In this application, the terms "comprise" or "have" and the like are intended to specify the presence of any feature, number, step, operation, component, part, or combination thereof described in the specification, and should be understood not to preclude the presence or possible addition of one or more other features, numbers, steps, operations, 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, a battery system 1 includes a battery 10 and a master BMS (Battery Management System, hereinafter referred to as master BMS) 20.

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

[0033] Hereinafter, when referring to a specific battery pack among the plurality of battery packs 10_1-10_n, reference numeral "10_j" will be used, and the battery modules and slave BMSs included in the battery pack 10_j will be referred to by reference numerals "100j" and "200j," respectively. Furthermore, the capacitors, inductors, contacts, and antennas included in the battery pack 10_j described below will be referred to by reference numerals "Cj," "Lj," "Nj," and "200_Aj," respectively.

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

[0035] The battery module 100j may include a plurality of battery cells connected in series and / or parallel. In one embodiment, the battery cells may be rechargeable secondary batteries. While FIGS. 1 and 2 illustrate the battery module 100j including three battery cells Cell1, Cell2, and Cell3 connected in series, the battery module 100j is not limited thereto. The battery module 100j may include any number of battery cells.

[0036] The slave BMS 200j can collect battery data for the battery module 100j and wirelessly transmit the collected battery data to the master BMS 20. At this time, the battery data can include at least one of the cell voltage, cell current, and cell temperature of each of the plurality of battery cells Cell1, Cell2, and Cell3. The battery data can also include at least one of the module voltage, which is the voltage across both ends of 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 to collect battery data. For example, the monitoring unit 210 may be configured as an integrated circuit (IC) capable of collecting battery data, such as an application specific IC (ASIC) or a battery monitoring IC (BMIC).

[0039] 2, for example, the monitoring unit 210 is electrically connected to the positive and negative electrodes of each of the plurality of battery cells Cell1, Cell2, and Cell3 and measures the cell voltages of each of the plurality of battery cells Cell1, Cell2, and Cell3. For another example, the monitoring unit 210 may receive information about the cell current and cell temperature measured by a current sensor (not shown) and a temperature sensor (not shown), respectively. For another example, the monitoring unit 210 may measure the cell voltages of each of the plurality of battery cells Cell1, Cell2, and Cell3 at predetermined intervals during a rest period in which no charging or discharging occurs, and calculate the cell current based on the measured cell voltages. The monitoring unit 210 may collect battery data at predetermined intervals 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 that needs to be transmitted. For example, the communication unit 220 may be configured from an RFIC (Radio Frequency IC), but is not limited to this.

[0041] Depending on the embodiment, the control unit 230 may convert a digital signal into an analog signal (AC signal) and transmit it to the communication unit 220. The communication unit 220 then 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. The antenna may be an antenna generated in an antenna mode depending on the embodiment, and a detailed description thereof will be given below with reference to FIGS. 4 and 5.

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

[0043] The capacitor Cj may be connected between the communication unit 220 and a first ground GND1. In this case, the first ground GND1 may be, but is not limited to, a signal ground located in the slave BMS 200j. For example, the first ground GND1 may be an earth ground or a chassis ground.

[0044] The inductor Lj may be connected between a node Nj between the first ground GND1 and the capacitor Cj and a second ground GND2. In this case, the second ground GND2 may be, but is not limited to, a chassis ground located in the battery module 100j. For example, the second ground GND2 may be an earth ground or a signal ground.

[0045] 2, the inductor Lj may be disposed 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 disposed outside the housing of the slave BMS 200j.

[0046] The master BMS 20 communicates with the upper controller 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. In this case, the upper controller 2 may be a controller of a higher-level system (e.g., an automobile, an ESS system, etc.) in which the battery system 1 is installed.

[0047] 1, depending on the embodiment, the master BMS 20 can transmit various control signals or receive battery data by wirelessly communicating with each of the multiple slave BMSs 2001-200N. The external device shown in FIG. 1 can be a charger in a charging mode that charges the battery 10, or a load (e.g., a motor) in a discharging mode that discharges the battery 10.

[0048] The slave BMS 200j according to the embodiment does not need a separate antenna device to be able to wirelessly communicate with the master BMS 20. This will be described in detail below with reference to FIGS.

[0049] FIG. 3 is a block diagram illustrating in detail the battery pack of FIG. 1 operating in monitoring mode, FIG. 4 is a block diagram illustrating in detail the battery pack of FIG. 1 operating in antenna mode, and FIG. 5 is a block diagram illustrating in detail the antenna of FIG. 4.

[0050] Depending on the 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 will describe in detail the structure of the battery pack 10_j in the monitoring mode, and Figs. 4 and 5 will describe in detail the structure of the battery pack 10_j in the antenna mode.

[0051] Referring to FIG. 3, in the monitoring mode, the control unit 230 controls the communication unit 220 to transmit a DC signal to the capacitor Cj.

[0052] When a direct current (DC) signal is applied to capacitor Cj, the electrical characteristics of capacitor Cj, which is open by the DC signal, form a circuit as shown in Figure 3. That is, one end of inductor Lj is connected to first ground GND1, and the other end of inductor Lj is connected to second ground GND2. In this case, external noise can be removed by inductor Lj.

[0053] Referring to FIG. 4, in the antenna mode, the control unit 230 controls the communication unit 220 to transmit an AC signal having a predetermined frequency to the capacitor Cj.

[0054] When an alternating current (AC) signal is applied to capacitor Cj, the electrical characteristics of inductor Lj, which is opened by the AC signal, form a circuit as shown in Figure 4. Specifically, a transmission line (shown in bold) connecting a first end connected to capacitor Cj, a second end connected to first ground GND1, and a third end adjacent to inductor Lj, can function as an inverted-F antenna. That is, in an antenna mode for communicating with an external device (e.g., a master BMS), an antenna Aj corresponding to an inverted-F antenna structure can be formed in slave BMS 200j.

[0055] An inverted-F antenna is an antenna designed to improve the impedance matching of an inverted-L antenna. In this case, the inverted-L antenna may be an antenna created by bending approximately 80% of the top length of a monopole antenna horizontally to reduce its height.

[0056] 4, for example, the antenna 200_Aj may convert an AC signal input through the communication unit 220 into an electromagnetic wave and transmit the converted electromagnetic wave into the air. In another example, the antenna Aj may receive an electromagnetic wave, convert the received electromagnetic wave into an AC signal, and transmit the converted AC signal to the communication unit 220.

[0057] 5, according to an embodiment, the antenna 200_Aj may resonate at a frequency having a wavelength (λ) four times the antenna length AL. Specifically, the inverted-F antenna may be configured with an antenna length (AL=λ / 4) corresponding to one-quarter of the wavelength (λ) of the signal to be transmitted or received. In this case, the antenna length AL may correspond to the length between the inductor Lj and the first ground GND1.

[0058] For example, to transmit and receive signals corresponding to a frequency of 2.45 GHz, the antenna length AL can be configured to be 30.61 mm. In another example, to transmit and receive signals corresponding to a frequency of 915 MHZ, the antenna length AL can be configured to be 81.97 mm.

[0059] Depending on the embodiment, the antenna length AL may be determined by the position (mounting distance) of the inductor Lj. That is, by simply changing the mounting position of the inductor Lj, the slave BMS 200j can wirelessly communicate with the master BMS 20 in various ISM (Industrial Scientific and Medical) frequency bands.

[0060] FIG. 6 is a flowchart illustrating a wireless communication method according to one embodiment.

[0061] Hereinafter, a wireless communication method and a battery system that provides the method will be described with reference to FIGS.

[0062] Referring to FIG. 6, first, the monitoring unit 210 collects battery data (S100).

[0063] The monitoring unit 210 may 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 a cell voltage, a cell current, and a cell temperature of each of the plurality of battery cells Cell1, Cell2, and Cell3. In addition, the battery data may include at least one of a module voltage, which is a voltage across both ends of the battery module 100j, and a module current, which is a current flowing through the battery module 100j.

[0064] In step S100, the control unit 230 controls the communication unit 220 to transmit a direct current (DC) signal to the capacitor Cj. Specifically, when a direct current (DC) signal is applied to the capacitor Cj during a monitoring mode in which the monitoring unit 210 collects battery data, a circuit as shown in FIG. 3 is formed due to the electrical characteristics of the capacitor Cj, which is opened by the DC signal. That is, both ends of the capacitor Cj are connected to a first ground GND1 and a second ground GND2, respectively, and an inductor Lj is located between the first ground GND1 and the second ground GND2. At this time, external noise can be removed by the inductor Lj. As a result, the monitoring unit 210 can collect battery data with little influence from external noise.

[0065] Next, the control unit 230 transmits the collected battery data to the master BMS 20 through the communication unit 220 (S200).

[0066] According to one embodiment, the control unit 230 may transmit battery data to the master BMS 20 through the communication unit 220. According to another embodiment, the control unit 230 may transmit various information or receive control signals through wireless communication with the outside through the communication unit 220. In this case, the outside may be the master BMS 20, but is not limited thereto, and may include various devices located outside the slave BMS 200j.

[0067] In step S200, the control unit 230 may control the communication unit 220 to transmit an AC signal having a predetermined frequency to the capacitor Cj. Specifically, when an AC (Alternating Current) signal is applied to the capacitor Cj, a circuit as shown in FIG. 4 is formed due to the electrical characteristics of the inductor Lj, which is opened by the AC signal. Specifically, a transmission line (shown in bold) connecting a first end connected to the capacitor Cj, a second end connected to the first ground GND1, and a third end adjacent to the inductor Lj may function as an inverted-F antenna. That is, in an antenna mode step for communicating with the outside, an antenna 200_Aj corresponding to an inverted-F antenna structure may be formed in the slave BMS 200j.

[0068] An inverted-F antenna is an antenna designed to improve the impedance matching of an inverted-L antenna. In this case, the inverted-L antenna may be an antenna created by bending approximately 80% of the top length of a monopole antenna horizontally to reduce its height.

[0069] 5, for example, the antenna 200_Aj may convert an AC signal input through the communication unit 220 into an electromagnetic wave and transmit the converted electromagnetic wave into the air. In another example, the antenna 200_Aj may receive an electromagnetic wave, convert the received electromagnetic wave into an AC signal, and transmit the converted AC signal to the communication unit 220.

[0070] 4, according to an embodiment, the antenna 200_Aj may resonate at a frequency having a wavelength (λ) four times the antenna length AL. Specifically, the inverted-F antenna may be configured with an antenna length (AL=λ / 4) corresponding to one-quarter of the wavelength (λ) of the signal to be transmitted or received. In this case, the antenna length AL may correspond to the length between the inductor Lj and the first ground GND1.

[0071] For example, to transmit and receive signals corresponding to a frequency of 2.45 GHz, the antenna length AL can be configured as 30.61 mm. As another example, to transmit and receive signals corresponding to a frequency of 915 MHZ, the antenna length AL can be configured as 81.97 mm.

[0072] Depending on the embodiment, the antenna length AL may be determined by the position (mounting distance) of the inductor Lj. That is, by simply changing the mounting position of the inductor Lj, the slave BMS 200j can wirelessly communicate with the master BMS 20 in various ISM (Industrial Scientific and Medical) frequency bands.

[0073] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to these, and various modifications and improvements made by those skilled in the art to which the present invention pertains also fall within the scope of the present invention.

Claims

1. A battery system including at least one battery pack including a battery module and a slave BMS 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 coupled between a junction between the first ground and the capacitor and a second ground; and a control unit that transmits an AC signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with the outside, controls the communication unit to transmit the AC signal to the capacitor, and forms an antenna using a transmission line that connects a first end connected to the capacitor, a second end connected to the first ground, and a third end adjacent to the inductor. Including the battery system.

2. The battery system according to claim 1 , wherein the inductor is located between the battery module and the slave BMS.

3. The battery system of claim 2 , wherein a length between the inductor and the first ground corresponds to ¼ of a wavelength of the AC signal.

4. The first ground is a signal ground of the slave BMS, The battery system according to claim 3 , wherein the second ground is a chassis ground of the battery module.

5. 10. The battery system of claim 1, further comprising a monitoring unit electrically connected to each of a plurality of battery cells included in the battery module and configured to collect battery data including at least one of a current, a voltage, and a temperature of each of the plurality of battery cells.

6. The battery system of claim 5 , wherein the control unit transmits a DC signal to the communication unit in a monitoring mode in which the monitoring unit collects the battery data.

7. The battery system according to claim 6 , further comprising a master BMS that wirelessly communicates with the communication unit and manages the at least one slave BMS.

8. The battery system of claim 7 , wherein the control unit transmits the collected battery data to the master BMS through the communication unit in the antenna mode.

9. A method for wireless communication in a battery system including: a communication unit of a slave BMS that manages a battery module; a capacitor connected between the communication unit and a first ground; and an inductor connected between a junction between the first ground and the capacitor and a second ground, transmitting an AC signal having a predetermined frequency to the communication unit, controlling the communication unit to transmit the AC signal to the capacitor, forming an antenna using a transmission line connecting a first end connected to the capacitor, a second end connected to the first ground, and a third end adjacent to the inductor, and communicating with the outside through the antenna by the slave BMS. A wireless communication method comprising:

10. The wireless communication method according to claim 9 , wherein the inductor is located between the battery module and the slave BMS.

11. The wireless communication method according to claim 10 , wherein the length between the inductor and the first ground corresponds to ¼ of the wavelength of the AC signal.

12. The first ground is a signal ground of the slave BMS, The wireless communication method according to claim 11 , wherein the second ground is a chassis ground of the battery module.

13. The battery system includes: a monitoring unit electrically connected to each of the plurality of battery cells included in the battery module, and configured to collect battery data including at least one of a current, a voltage, and a temperature of each of the plurality of battery cells; The wireless communication method of claim 9, further comprising:

14. The method further includes a step of the monitoring unit collecting the battery data before the step of communicating with the outside, The wireless communication method of claim 13 , wherein collecting the battery data comprises transmitting a DC signal to the communication unit.

15. The wireless communication method of claim 14 , wherein the communicating with the outside comprises transmitting the collected battery data to a master BMS that manages the slave BMS through the communication unit.

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