Battery System

Abstract

The present invention relates to a battery system capable of wireless communication between a plurality of battery management systems (BMSs), and includes at least one battery module including a battery cell component and a slave BMS (Battery Management System) that manages the battery cell component. The battery system of the present invention includes a communication unit of the slave BMS, a capacitor connected between the communication unit and a first ground, a first inductor and a second inductor connected in series between a contact point of 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, and the second inductor is configured with a wire so that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS with which communication is to be performed.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0103594 dated August 8, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

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

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

[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 associated with wire cables and connectors, and to increase the driving range of electric vehicles by reducing their weight. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a battery system that enables wireless communication between a plurality of BMSs (Battery Management Systems) without adding a separate component for wireless communication.

[0006] An object of the present invention is to provide a battery system that is capable of antenna impedance matching with a simple configuration.

[0007] An object of the present invention is to provide a battery system capable of wireless communication between a plurality of Battery Management Systems (BMS) in various ISM (Industrial Scientific and Medical) bands. [Means for solving the problem]

[0008] According to one aspect of the present invention, a battery system includes at least one battery module including a battery cell component and a slave BMS (Battery Management System) that manages the battery cell component, the battery system including: a communication unit of the slave BMS; a capacitor connected between the communication unit and a first ground; a first inductor and a second inductor connected in series between a contact point of 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, and the second inductor is configured with a wire so that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS with which communication is to be performed.

[0009] At least one of the number of wires, the thickness of the wires, the length of the wires, and the spacing between adjacent wires of the second inductor may be determined so that the first antenna impedance and the second antenna impedance are matched.

[0010] The first inductor and the second inductor may be located between the battery cell component and the slave BMS.

[0011] The length between the second inductor, which is located farther from the contact point than the first inductor, and the first ground can correspond to ¼ of the wavelength of the AC signal.

[0012] The first ground may be a signal ground of the slave BMS, and the second ground may be a chassis ground of the battery cell component.

[0013] The battery system may further include a monitoring unit electrically connected to each of the plurality of battery cells included in the battery cell component 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.

[0014] 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.

[0015] The battery system may further include a master BMS that wirelessly communicates with the communication unit and manages the at least one slave BMS.

[0016] The control unit may transmit the collected battery data to the master BMS through the communication unit in the antenna mode.

[0017] The first inductor may be configured in the form of a chip having a preset impedance value. [Effects of the Invention]

[0018] The present invention enables wireless communication and antenna impedance matching with a simple configuration, thereby reducing the size of the PCB (Printed Circuit Board) that constitutes the slave BMS and saving costs.

[0019] The present invention does not require changing the BMS PCB depending on the frequency band, and therefore allows for a commonization design of the BMS PCB. [Brief explanation of the drawings]

[0020] [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 module of FIG. 1 in detail. [Figure 3] FIG. 2 is a block diagram illustrating in detail when the battery module of FIG. 1 operates in a monitoring mode. [Figure 4] FIG. 2 is a block diagram illustrating in detail when the battery module 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] FIG. 2 is a diagram illustrating an example of a Smith chart for explaining antenna matching according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, the embodiments disclosed herein will be described in detail with reference to the accompanying drawings. Identical or similar components will be designated by identical or similar reference numerals, and redundant description thereof will be omitted. The suffixes "module" and / or "section" for components used in the following description are assigned or used interchangeably solely for ease of description and do not have any distinct meanings or functions. Furthermore, when describing the embodiments disclosed herein, if it is determined that a detailed description of related publicly known technology may obscure the gist of the embodiments disclosed herein, such a detailed description will be omitted. Furthermore, the accompanying drawings are intended to facilitate understanding of the embodiments disclosed herein, and should not be construed as limiting the technical concepts disclosed herein, and should be understood to include all modifications, equivalents, or alternatives within the concept and technical scope of the present invention.

[0022] 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.

[0023] 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.

[0024] 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 stated in the specification, and should be understood as not precluding the presence or possible addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0025] FIG. 1 is a block diagram illustrating a battery system according to an embodiment, and FIG. 2 is a block diagram illustrating a battery module of FIG. 1 in detail.

[0026] 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.

[0027] The battery 10 includes at least one battery module. Although a plurality of battery modules 10_1-10_n are shown in FIG. 1, the battery 10 is not limited thereto, and may include only one battery module 10_1.

[0028] Hereinafter, when referring to a specific battery module among the plurality of battery modules 10_1-10_n, reference numeral "10_j" will be used, and the battery cell components and slave BMS included in the battery module 10_j will be referred to by reference numerals "100j" and "200j," respectively. Furthermore, the capacitors, inductors, contacts, and antennas included in the battery module 10_j described below will be referred to by reference numerals "Cj," "Lj," "Nj," and "200_Aj," respectively.

[0029] The battery module 10_j includes a battery cell component 100j and a slave BMS 200j.

[0030] The battery cell component 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 cell component 100j including three battery cells Cell1, Cell2, and Cell3 connected in series, the present invention is not limited thereto. The battery cell component 100j may include various numbers of battery cells.

[0031] The slave BMS 200j can collect battery data for the battery cell component 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 cell component 100j, and the module current, which is the current flowing through the battery cell component 100j.

[0032] Referring to FIG. 2, the slave BMS 200j may include a monitoring unit 210j, a communication unit 220j, a control unit 230j, a capacitor Cj, a first inductor L1-j, and a second inductor L2-j.

[0033] The monitoring unit 210j is electrically connected to a plurality of battery cells Cell1, Cell2, and Cell3 to collect battery data. For example, the monitoring unit 210j is an integrated circuit (IC) capable of collecting battery data, and may be configured as an application specific IC (ASIC), a battery monitoring IC (BMIC), or the like.

[0034] 2, for example, the monitoring unit 210j 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. As another example, the monitoring unit 210j may receive information on the cell current and cell temperature measured by a current sensor (not shown) and a temperature sensor (not shown), respectively. As another example, the monitoring unit 210j 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 210j may collect battery data at predetermined intervals or in real time, and transmit the collected battery data to the control unit 230j.

[0035] The communication unit 220j may be an analog signal processing device that processes data that needs to be transmitted. For example, the communication unit 220j may be configured as an RFIC (Radio Frequency IC), but is not limited to this.

[0036] According to an embodiment, the control unit 230j may convert a digital signal into an analog signal (AC signal) and transmit the signal to the communication unit 220j. The communication unit 220j then amplifies, filters, and processes the analog signal, 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 according to an embodiment, and details of the antenna will be described below with reference to FIGS. 4 and 5.

[0037] The control unit 230j may control the overall operation of the slave BMS 200j. For example, the control unit 230j may control the monitoring unit 210j to collect battery data and the communication unit 220j to transmit the collected battery data to the master BMS 20.

[0038] The capacitor Cj may be connected between the communication unit 220j and a first ground GND1-j. In this case, the first ground GND1-j may be, but is not limited to, a signal ground located in the slave BMS 200j. For example, the first ground GND1-j may be embodied as an earth ground or a chassis ground.

[0039] The first inductor L1-j and the second inductor L2-j may be coupled between the first ground GND1-j and the node Nj of the capacitor Cj and the second ground GND2-j. For example, when the battery cell component 100j and the slave BMS 200j are coupled by a flexible printed circuit board (FPCB), the first inductor L1-j and the second inductor L2-j may be formed on the FPCB. As another example, when the battery cell component 100j and the slave BMS 200j are coupled by wiring, the first inductor L1-j and the second inductor L2-j may be formed on the wiring.

[0040] 2, according to an embodiment, the first inductor L1-j and the second inductor L2-j may be located in an external space between the battery cell component 100j and the slave BMS 200j. Specifically, the other end of the first inductor L1-j connected to the contact Nj may be located outside the housing of the slave BMS 200j. Also, one end of the second inductor L2-j connected to the second ground GND2-j may be located outside the housing of the battery cell component 100j. In this case, the second ground GND2-j may be, but is not limited to, a chassis ground located in the battery cell component 100j. For example, the second ground GND2-j may be implemented as an earth ground or a signal ground.

[0041] The first inductor L1-j may be configured in the form of a chip having a preset impedance value. For example, the first inductor L1-j may be mounted on an FPCB that connects the battery cell component 100j and the slave BMS 200j using surface mount technology (SMT). SMT is a technology in which solder paste is printed on an FPCB substrate and chip components are mounted on the solder paste using reflow to bond the FPCB and chip components.

[0042] According to an embodiment, the first inductor L1-j configured in a chip form may be standardized in predetermined size intervals such as 30H, 50H, 100H, etc. In other words, the first inductor L1-j has a large inductance, but may have a limitation in that it is difficult to precisely tune the impedance.

[0043] The second inductor L2-j may be formed of a wire. According to an embodiment, the second inductor L2-j may be small in size but may enable precise impedance tuning. For example, increasing the number of wires constituting the second inductor L2-j may reduce the inductance (L) and resistance (R). Increasing the thickness of the wires constituting the second inductor L2-j may reduce the resistance (R). Changing the material of the wires constituting the second inductor L2-j may change the inductance (L) and resistance (R) values ​​according to the characteristics of the material. Increasing the length of the wires constituting the second inductor L2-j may increase the inductance (L). Increasing the separation distance between the multiple wires constituting the second inductor L2-j may increase the capacitance (C). A specific method for tuning the impedance by changing the number, thickness, material, and length of the wires constituting the second inductor L2-j will be described below with reference to FIG. 6.

[0044] The master BMS 20 can wirelessly communicate with each of the multiple slave BMSs to transmit various control signals and receive battery data. The slave BMS 200j according to the embodiment can wirelessly communicate with the master BMS 20 without including a separate antenna device. This will be described in detail below with reference to FIGS. 4 and 5.

[0045] FIG. 3 is a block diagram illustrating in detail the battery module of FIG. 1 operating in monitoring mode, FIG. 4 is a block diagram illustrating in detail the battery module of FIG. 1 operating in antenna mode, and FIG. 5 is a block diagram illustrating in detail the antenna of FIG. 4.

[0046] According to the embodiment, the battery module 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 explain in detail the structure of the battery module 10_j in the monitoring mode, and Figs. 4 and 5 will explain in detail the structure of the battery module 10_j in the antenna mode.

[0047] Referring to FIG. 3, in the monitoring mode, the control unit 230j can control the communication unit 220j to transmit a DC signal to the capacitor Cj.

[0048] When a direct current (DC) signal is applied to capacitor Cj, the electrical characteristics of capacitor Cj, which is open when the DC signal is applied, form a circuit as shown in Figure 3. That is, the other end of first inductor L1-j may be connected to first ground GND1-j, and one end of second inductor L2-j may be connected to second ground GND2-j. In this case, external noise may be filtered out by first inductor L1-j and second inductor L2-j.

[0049] Referring to FIG. 4, in the antenna mode, the control unit 230j controls the communication unit 220j to transmit an AC signal having a predetermined frequency to the capacitor Cj.

[0050] When an alternating current (AC) signal is applied to the capacitor Cj, a circuit as shown in FIG. 4 can be formed due to the electrical characteristics of the first inductor L1-j and the second inductor L2-j, which are opened by the AC signal.

[0051] Even when an AC signal passes through the first inductor L1-j, the inductors after the first inductor L1-j are not completely open, and some of the AC signal remains. After that, when the AC signal passes through the second inductor L2-j, almost no AC signal remains. In Figure 5, the darker the color, the stronger the RF AC signal component, and the second inductor L2-j can act as an antenna.

[0052] 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-j, and a third end adjacent to the second inductor L2-j 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 the slave BMS 200j.

[0053] An inverted-F antenna is an antenna designed to improve the impedance matching of an inverted-L antenna. In this case, an inverted-L antenna can be an antenna created by bending about 80% of the top length of a monopole antenna horizontally to reduce its height.

[0054] 4, for example, antenna Ant-j may convert an AC signal input through communication unit 220j into an electromagnetic wave and transmit the converted electromagnetic wave into the air. As another example, antenna Aj may receive an electromagnetic wave, convert the received electromagnetic wave into an AC signal, and transmit the converted AC signal to communication unit 220j.

[0055] According to an embodiment, the antenna Ant-j 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 may correspond to the length (AL-j) between the second inductor L2-j and the first ground GND1-j.

[0056] For example, to transmit and receive signals corresponding to a frequency of 2.45 GHZ, the antenna length (AL) may 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) may be configured as 81.97 mm.

[0057] According to an embodiment, the antenna length (AL-j) may be determined by the positions (mounting distance) of the first inductor L1-j and the second inductor L2-j. That is, by simply changing the mounting positions of the first inductor L1-j and the second inductor L2-j, the slave BMS 200j can wirelessly communicate with the master BMS 20 in various ISM (Industrial Scientific and Medical) frequency bands.

[0058] FIG. 6 is a diagram illustrating an example of a Smith chart for explaining antenna matching according to an embodiment.

[0059] If impedance mismatch occurs in an antenna system, reflected waves can occur, resulting in power loss. In other words, when connecting two circuits, such as a signal source and a load, impedance matching is required to prevent reflection loss. Impedance matching of sensitive receiver components can improve the signal-to-noise ratio (SNR) and linearize frequency characteristics.

[0060] According to an embodiment, in wireless communication between the slave BMS 200j and the master BMS 20, one of them may be a signal source and the other may be a load. For convenience of explanation, the following describes impedance matching, which matches the impedance of the slave BMS 200j to the impedance of the master BMS 20. That is, the impedance of the slave BMS 200j will be referred to as the load impedance, and the impedance of the master BMS 20 will be referred to as the signal source impedance.

[0061] 6 is an example of a Smith chart, which may be a combination of an impedance chart and an admittance chart. Both the impedance chart and the admittance chart are well known and therefore drawings and descriptions thereof will be omitted. According to an embodiment, impedance matching can be explained using the Smith chart.

[0062] According to an embodiment, when the second inductor L2-j is varied for impedance matching using a Smith chart, as the inductance component increases, it moves along the upper direction of the concentric circles of the Smith chart, and as the capacitance component increases, it moves along the lower direction of the concentric circles of the Smith chart.

[0063] When only the first inductor L1-j in a standardized chip form is mounted, impedance mismatch, i.e., deviation, may occur between the master BMS 20 and the slave BMS 200j. For example, in FIG. 6, the first coordinate (1) is assumed to be the load impedance corresponding to the slave BMS 200j when only the first inductor L1-j is mounted, and the third coordinate (3) is assumed to be the signal source impedance corresponding to the master BMS 20. In order to match the first coordinate (1) with the third coordinate (3), at least one of the number of wires constituting the second inductor L2-j, the wire thickness, the wire length, and the spacing between adjacent wires may be determined.

[0064] For example, increasing the number of wires constituting the second inductor L2-j can reduce the inductance (L) and resistance (R). Increasing the thickness of the wires constituting the second inductor L2-j can reduce the resistance (R). Changing the material of the wires constituting the second inductor L2-j can change the inductance (L) and resistance (R) values ​​according to the characteristics of the material. Increasing the length of the wires constituting the second inductor L2-j can increase the inductance (L). Increasing the separation distance between the wires constituting the second inductor L2-j can increase the capacitance (C) value.

[0065] According to the embodiment, after the first inductor L1-j is mounted, impedance tuning can be performed using the second inductor L2-j to achieve impedance matching. The user can select various loci on the Smith chart to move the first coordinate (1) to the target third coordinate (3). For example, in FIG. 6, assume that the first coordinate (1) is moved to the second coordinate (2), and then the second coordinate (2) is moved to the target third coordinate (3).

[0066] Referring to FIG. 6, in order to move from the first coordinate (1) to the second coordinate (2), the Smith chart requires moving upward on the concentric circles, which requires an increase in the inductance component. For example, as described above, the length of the wire constituting the second inductor L2-j can be increased to significantly increase the inductance component. In order to move from the second coordinate (2) to the third coordinate (3), the Smith chart requires moving downward on the concentric circles, which requires an increase in the capacitance component. For example, as described above, the separation distance between the wires constituting the second inductor L2-j can be increased to significantly increase the capacitance component. However, this is not limited to this example, and the number, thickness, length, and spacing between adjacent wires of the wires constituting the second inductor L2-j can be comprehensively changed to match the first coordinate (1) with the third coordinate (3).

[0067] 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 a person having ordinary skill 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 module including a battery cell component and a slave BMS that manages the battery cell component, a communication unit of the slave BMS; a capacitor connected between the communication unit and a first ground; a first inductor and a second inductor connected in series between the first ground and a junction of the capacitor and a second ground; 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 an external device, The second inductor is A battery system configured with wires such that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS with which communication is intended.

2. The second inductor is 2. The battery system of claim 1, wherein at least one of the number of wires, the thickness of the wires, the length of the wires, and the spacing between adjacent wires is determined so that the first antenna impedance and the second antenna impedance are matched.

3. The first inductor and the second inductor are The battery system according to claim 2 , which is located between the battery cell component and the slave BMS.

4. The length between the second inductor, which is located farther from the contact point than the first inductor, and the first ground is 4. The battery system of claim 3, wherein the wavelength corresponds to one-quarter of the wavelength of the AC signal.

5. The first ground is a signal ground of the slave BMS, The battery system according to claim 1 , wherein the second ground is a chassis ground of the battery cell component.

6. 6. The battery system according to claim 5, further comprising a monitoring unit electrically connected to each of the plurality of battery cells included in the battery cell configuration unit 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.

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

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

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

10. The first inductor is The battery system of claim 1 , wherein the battery system is configured in a chip form having a preset impedance value.

Images