Battery system

Abstract

The present disclosure relates to a battery system capable of wireless communication between a plurality of battery management systems (BMSs). The battery system includes at least one battery module including a battery cell configuration unit and a slave battery management system (BMS) managing the battery cell configuration unit, the battery system including: a communication unit of the slave BMS; a capacitor connected between the communication unit and the first ground; a first inductor and a second inductor connected in series between a contact between the first ground and the capacitor and the 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 communication is performed from the BMS to the outside, in which the second inductor is configured by the wire such that the first antenna impedance determined by the first inductor is matched with the second antenna impedance of the main BMS that is a communication target.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0103594 filed in the Korean Intellectual Property Office on August 8, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present disclosure relates to a battery system capable of wireless communication between a plurality of battery management systems (BMSs). Background Art

[0004] A battery system applied to an electric vehicle or the like may include a plurality of battery modules including a battery cell configuration unit and a slave battery management system (BMS) managing the battery cell configuration unit. In addition, the battery system may further include a master battery management system (BMS) that communicates with the vehicle system and manages the plurality of battery modules.

[0005] In recent years, research and development on methods for wireless communication between a master BMS and a plurality of slave BMSs has increased in order to solve problems such as poor quality and frequent maintenance issues of electrical wiring related to wire cables and connectors, and to increase mileage by reducing the weight of electric vehicles. Summary of the invention

[0006] Technical issues

[0007] The present disclosure attempts to provide a battery system capable of wireless communication between a plurality of battery management systems (BMS) without adding a separate component for wireless communication.

[0008] The present disclosure provides a battery system capable of performing impedance matching of an antenna with a simple configuration.

[0009] The present disclosure provides a battery system capable of wireless communication between a plurality of battery management systems (BMS) in various industrial scientific and medical frequency bands (ISM frequency bands).

[0010] Technical Solution

[0011] According to one aspect of the present disclosure, a battery system includes: at least one battery module, the at least one battery module including a battery cell configuration unit and a slave battery management system (BMS) that manages the battery cell configuration unit, the battery system includes: a communication unit of the slave BMS; a capacitor, which is connected between the communication unit and a first ground; a first inductor and a second inductor, the first inductor and the second inductor are connected in series between a contact portion between the first ground and the capacitor and the second ground; and a control unit, which sends an AC signal with a predetermined frequency to the communication unit in an antenna mode for communicating with the outside from the BMS, wherein the second inductor is configured by a wire so that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS as a communication target.

[0012] For the second inductor, at least one of the number of conductive lines, thickness of the conductive lines, length of the conductive lines, and spacing between adjacent conductive lines may be determined so that the first antenna impedance matches the second antenna impedance.

[0013] The first inductor and the second inductor may be located between the battery cell configuration unit and the slave BMS.

[0014] A length between the second inductor and the first ground may correspond to 1 / 4 of a wavelength of the AC signal, and the second inductor is farther from the contact portion than the first inductor.

[0015] The first ground may be a signal ground from the BMS, and the second ground may be a chassis ground of the battery cell configuration unit.

[0016] The battery system may further include a monitoring unit electrically connected to each of the plurality of battery cells included in the battery cell configuration unit and collecting battery data including at least one of current, voltage, and temperature of each of the plurality of battery cells.

[0017] The control unit may send the DC signal to the communication unit in a monitoring mode in which the monitoring unit collects battery data.

[0018] The battery system may further include a master BMS which manages the at least one slave BMS by wirelessly communicating with the communication unit.

[0019] The control unit may transmit the collected battery data to the main BMS through the communication unit in the antenna mode.

[0020] The first inductor may be configured in the form of a chip having a preset impedance value.

[0021] Beneficial Effects

[0022] According to the present disclosure, since wireless communication and impedance matching of an antenna can be achieved with a simple configuration, a size of a printed circuit board (PCB) constituting a slave BMS can be reduced and costs can be reduced.

[0023] According to the present disclosure, since the BMS PCB does not need to be changed according to the frequency band, a universal design of the BMS PCB can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a block diagram for describing a battery system according to an embodiment.

[0025] Figure 2 It is shown in detail Figure 1 Block diagram of the battery module.

[0026] Figure 3 It is shown in detail Figure 1 A block diagram of a battery module when it operates in a monitoring mode.

[0027] Figure 4 It is shown in detail Figure 1 Block diagram of a battery module when it operates in antenna mode.

[0028] Figure 5 It is used to describe in detail Figure 4 Block diagram of the antenna.

[0029] Figure 6 is an example of a Smith chart for describing antenna matching according to an exemplary embodiment. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar components are given the same reference numerals and are not described repeatedly. The suffixes "module" and / or "unit" of the components used in the following description are given or mixed only for the ease of writing the specification, and therefore do not have meanings or roles that are distinguished from each other in them. In addition, when it is determined that the detailed description of the known technology related to the present specification in describing the exemplary embodiments disclosed in the present specification may unnecessarily confuse the main points of the exemplary embodiments disclosed in the present specification, the detailed description will be omitted. In addition, it should be understood that the drawings are provided only to allow easy understanding of the exemplary embodiments of the present disclosure, and the spirit of the present disclosure is not limited by the drawings, but includes all modifications, equivalents and substitutions included in the spirit and scope of the present disclosure.

[0031] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited to these terms. The above terms are used only for the purpose of distinguishing one component from another.

[0032] In this specification, it should be understood that when a component is referred to as being “connected to” or “coupled to” another component, it may be directly connected or coupled to the other component or connected to the other component with other components interposed therebetween. On the other hand, it should be understood that when an element is referred to as being “directly connected to” or “directly coupled to” another element, it may be connected or coupled to the other element without other elements interposed therebetween.

[0033] It will also be understood that the terms "including" or "having" used in this specification specify the presence of the features, numbers, steps, operations, components, parts or their combinations mentioned in this specification, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or their combinations.

[0034] Figure 1 is a block diagram for describing a battery system according to an embodiment. Figure 2 It is shown in detail Figure 1 Block diagram of the battery module.

[0035] refer to Figure 1 The battery system 1 includes a battery 10 and a main battery management system (hereinafter referred to as a main BMS) 20 .

[0036] The battery 10 includes at least one battery module. Figure 1 , a plurality of battery modules 10_1 to 10_n are shown, but are not limited thereto, and the battery 10 may include one battery module 10_1.

[0037] Hereinafter, when indicating a specific battery module among the plurality of battery modules 10_1 to 10_n, reference numeral "10_j" is used, and a battery cell configuration unit and a slave BMS included in the corresponding battery module 10_j use reference numerals "100j" and "200j", respectively. In addition, a capacitor, an inductor, a contact portion, and an antenna included in the battery module 10_j described below are each indicated by reference numerals "Cj", "Lj", "Nj", "200_Aj".

[0038] The battery module 10_j includes a battery cell configuration unit 100j and a slave BMS 200j.

[0039] The battery cell configuration unit 100 may include a plurality of battery cells connected in series and / or in parallel. In some embodiments, the battery cells may be rechargeable secondary batteries. Figure 1 and Figure 2 , a battery cell configuration unit 100j including three battery cells Cell1, Cell2, and Cell3 connected in series is shown, but is not limited thereto. The battery cell configuration unit 100j may include various battery cells.

[0040] The slave BMS 200j may collect battery data of the battery cell configuration unit 100j and transmit the collected battery data to the master BMS 20 via wireless communication. In this case, 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 the battery cell configuration unit 100j, and a module current, which is a current flowing through the battery cell configuration unit 100j.

[0041] refer to Figure 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.

[0042] The monitoring unit 210j is electrically connected to the plurality of battery cells Cell1, Cell2 and Cell3 and collects battery data. For example, the monitoring unit 210j may be composed of an application specific integrated circuit (ASIC), a battery monitoring IC (BMIC), etc. as an integrated circuit (IC) capable of collecting battery data.

[0043] refer to Figure 2 For example, the monitoring unit 210j is electrically connected to the positive and negative electrodes of each of the multiple battery cells Cell1, Cell2, and Cell3, and measures the cell voltage of each of the multiple battery cells Cell1, Cell2, and Cell3. For another example, the monitoring unit 210j may receive information about the cell current and the cell temperature measured by each of the current sensor (not shown) and the temperature sensor (not shown). For another example, the monitoring unit 210j may measure the cell voltage of each of the multiple battery cells Cell1, Cell2, and Cell3 in a predetermined cycle during a rest period in which no charging or discharging occurs, and calculate the cell current based on the measured cell voltage. The monitoring unit 210j may collect battery data in a predetermined cycle or in real time, and send the collected battery data to the control unit 230j.

[0044] The communication unit 220j may be an analog signal processing device that processes data to be transmitted. For example, the communication unit 220j may be composed of a radio frequency IC (RFIC), but is not limited thereto.

[0045] According to an exemplary embodiment, the control unit 230j may convert the digital signal into an analog signal (AC signal) and transmit it to the communication unit 220j. Then, the communication unit 220j 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 form and transmit the electromagnetic wave into the air. The antenna may be an antenna generated in an antenna mode according to an exemplary embodiment, and will be referred to below. Figure 4 and Figure 5 To describe the detailed description.

[0046] The control unit 230 j may control the overall operation of the slave BMS 200 j , For example, the monitoring unit 210 j may be controlled to collect battery data, and the communication unit 220 j may be controlled to transmit the collected battery data to the master BMS 20 .

[0047] The capacitor Cj may be connected between the communication unit 220j and the first ground GND1-j. In this case, the first ground GND1-j may be a signal ground located in the slave BMS 200j, but is not limited thereto. For example, the first ground GND1-j may be implemented as a ground ground or a chassis ground.

[0048] The first inductor L1-j and the second inductor L2-j may be connected between the contact portion Nj between the first ground GND1-j and the capacitor Cj and the second ground GND2-j. For example, when the battery cell configuration unit 100j and the slave BMS 200j are connected to a flexible printed circuit board (FPCB), the first inductor L1-j and the second inductor L2-j may be formed on the FPCB. For another example, when the battery cell configuration unit 100j and the slave BMS 200j are connected with wiring, the first inductor L1-j and the second inductor L2-j may be formed on the wiring.

[0049] According to an exemplary embodiment, reference Figure 2 , the first inductor L1-j and the second inductor L2-j may be located in the external space between the battery cell configuration unit 100j and the slave BMS 200j. Specifically, the other end of the first inductor L1-j connected to the contact portion Nj may be located outside the housing of the slave BMS 200j. In addition, 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 configuration unit 100j. In this case, the second ground GND2-j may be a chassis ground located in the battery cell configuration unit 100j, but is not limited thereto. For example, the second ground GND2-j may be implemented as a ground ground or a signal ground.

[0050] 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 connecting the battery cell configuration unit 100j and the slave BMS 200j by surface mounting technology (SMT). Surface mounting technology (SMT) is a technology of printing solder paste on an FPCB substrate and mounting a chip component thereon using reflow to join the FPCB and the chip component.

[0051] According to an exemplary embodiment, the first inductor L1-j configured in the form of a chip may be standardized at a predetermined size interval such as 30H, 50H, or 100H. That is, the first inductor L1-j may have a large inductance, but may have limitations because it is difficult to accurately tune impedance.

[0052] The second inductor L2-j can be configured by a wire. According to an exemplary embodiment, the size of the second inductor L2-j can be small, but precise impedance tuning is enabled. For example, when the number of wires constituting the second inductor L2-j increases, the size of the inductance L and the resistance R can be reduced. In addition, when the thickness of the wire constituting the second inductor L2-j increases, the size of the resistance R can be reduced. In addition, when the material of the wire constituting the second inductor L2-j changes, the values ​​of the inductance L and the resistance R can change depending on the characteristics of the material. In addition, when the length of the wire constituting the second inductor L2-j increases, the size of the inductance L can increase. Furthermore, when the separation distance between the multiple wires constituting the second inductor L2-j increases, the value of the capacitance C can increase. The following will be related to Figure 6 A specific method of tuning impedance by changing the number, thickness, material, and length of the conductive wires constituting the second inductor L2 - j is described together.

[0053] The master BMS 20 may wirelessly communicate with each of the plurality of slave BMSs to transmit various control signals or receive battery data. The slave BMS 200j according to the exemplary embodiment may wirelessly communicate with the master BMS 20 without including a separate antenna device. This will be described below with reference to Figure 4 and Figure 5 Detailed description.

[0054] Figure 3 It is shown in detail Figure 1 A block diagram of a battery module when it operates in a monitoring mode. Figure 4 It is shown in detail Figure 1 Block diagram of a battery module when it operates in antenna mode. Figure 5 It is used to describe in detail Figure 4 Block diagram of the antenna.

[0055] According to an exemplary 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. Figure 3 The structure of the battery module 10_j in the monitoring mode is described in detail, and Figure 4 and Figure 5 The structure of the battery module 10_j in the antenna mode is described in detail.

[0056] refer to Figure 3 , in the monitoring mode, the control unit 230j may control the communication unit 220j to send a direct current (DC) signal to the capacitor Cj.

[0057] When a direct current (DC) signal is applied to the capacitor Cj, a capacitor Cj may be disconnected by the DC signal and may be disconnected by the DC signal. Figure 3 The circuit shown in . That is, the other end of the first inductor L1-j can be connected to the first ground GND1-j, and one end of the second inductor L2-j can be connected to the second ground GND2-j. In this case, external noise can be removed by the first inductor L1-j and the second inductor L2-j.

[0058] refer to Figure 4 , in the antenna mode, the control unit 230j may control the communication unit 220j to transmit an alternating current (AC) signal having a predetermined frequency to the capacitor Cj.

[0059] When an AC signal is applied to the capacitor Cj, a first inductor L1-j and a second inductor L2-j disconnected by the AC signal may be formed as follows: Figure 4 The circuit shown in .

[0060] Even though the AC signal passes through the first inductor L1-j, the area after the first inductor L1-j is not completely disconnected, and some of the AC signal remains. Then, when the AC signal passes through the second inductor L2-j, almost no AC signal remains. Figure 5 In FIG. 1 , the darker the color, the stronger the RF AC signal component can be, and the second inductor L2 - j can also be used as an antenna.

[0061] Specifically, the transmission line (bold part) connected among the first terminal connected to the capacitor Cj, the second terminal connected to the first ground GND1-j, and the third terminal adjacent to the second inductor L2-j can perform an inverted F antenna function. That is, in the antenna mode for communicating with the outside (e.g., the master BMS), the antenna Aj corresponding to the inverted F antenna structure can be formed in the slave BMS 200j.

[0062] The inverted-F antenna is an antenna formed to improve impedance matching of the inverted-L antenna. In this case, the inverted-L antenna may be an antenna formed by horizontally bending about 80% of the upper length of the monopole antenna to reduce its height.

[0063] refer to Figure 4 For example, the antenna Ant-j may convert an AC signal input through the communication unit 220j into an electromagnetic wave and transmit the converted electromagnetic wave into the air. As 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 220j.

[0064] According to an exemplary embodiment, the antenna Ant-j may resonate at a frequency at which the wavelength λ is four times the antenna length AL. Specifically, the inverted F antenna may be configured to have an antenna length (AL=λ / 4) corresponding to 1 / 4 of the wavelength λ of the signal to be transmitted and 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.

[0065] For example, to transmit and receive signals corresponding to a frequency of 2.45 GHz, the antenna length AL may 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 may be configured to be 81.97 mm.

[0066] According to an exemplary embodiment, the antenna length AL-j may be determined according to the position (installation distance) of the first inductor L1-j and the second inductor L2-j. That is, by a simple operation of changing the position where the first inductor L1-j and the second inductor L2-j are installed, the slave BMS 200j may wirelessly communicate with the master BMS 20 in various Industrial Science and Medical (ISM) bands.

[0067] Figure 6 is an example of a Smith chart for describing antenna matching according to an exemplary embodiment.

[0068] In an antenna system, if impedance mismatch occurs, a reflected wave may be generated, resulting in power loss. That is, when connecting two circuits such as a signal source and a load, it is necessary to achieve impedance matching so that there is no reflection loss. Impedance matching of sensitive receiver components can improve the signal-to-noise ratio (SNR) and linearize frequency characteristics.

[0069] According to an exemplary embodiment, in the wireless communication between the slave BMS 200j and the master BMS 20, one side may be a signal source and the other side may be a load. Hereinafter, for the convenience of description, impedance matching is described below in which the impedance of the slave BMS 200j is matched with the impedance of the master BMS 20. That is, the impedance of the slave BMS 200j is referred to as a load impedance, and the impedance of the master BMS 20 is referred to as a signal source impedance.

[0070] Figure 6 is an example of a Smith chart, and the Smith chart may be in the form of an impedance graph and an admittance graph superimposed on each other. Since the impedance graph and the admittance graph are each widely known in the past, the drawing and description are omitted. According to an exemplary embodiment, impedance matching may be described using a Smith chart.

[0071] According to an exemplary embodiment, when the second inductor L2-j is varied for impedance matching using the Smith chart, if the inductance component increases, it moves in the upward direction of the concentric circles of the Smith chart, and if the capacitance component increases, it moves in the downward direction of the concentric circles of the Smith chart.

[0072] In a state where only the first inductor L1-j of the standardized chip form is installed, impedance mismatch, that is, deviation, may occur between the master BMS 20 and the slave BMS 200j. Figure 6 , it is assumed that the first coordinate ① is the load impedance corresponding to the slave BMS 200j in a state where only the first inductor L1-j is installed, and the third coordinate ③ is 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 thickness of the wire, the length of the wire, and the spacing between adjacent wires may be determined.

[0073] For example, when the number of wires constituting the second inductor L2-j increases, the magnitude of the inductance L and the resistance R may decrease. In addition, when the thickness of the wire constituting the second inductor L2-j increases, the magnitude of the resistance R may decrease. In addition, when the material of the wire constituting the second inductor L2-j changes, the values ​​of the inductance L and the resistance R may change depending on the characteristics of the material. In addition, when the length of the wire constituting the second inductor L2-j increases, the magnitude of the inductance L may increase. In addition, when the separation distance between the plurality of wires constituting the second inductor L2-j increases, the value of the capacitance C may increase.

[0074] According to an exemplary embodiment, impedance matching can be achieved by performing impedance tuning using the second inductor L2-j after installing the first inductor L1-j. In order to move the first coordinate ① to the third coordinate ③ as a target point, which track of the Smith chart can be selected by the user in various ways. For example, in Figure 6 , it is assumed that after moving from the first coordinate ① to the second coordinate ②, the second coordinate ② is moved to the third coordinate ③ as the target coordinate.

[0075] refer to Figure 6 , in order to move from the first coordinate ① to the second coordinate ②, it is necessary to move in the upward direction of the concentric circles in the Smith chart, so it is necessary to increase the inductance component. For example, as described above, the length of the wire constituting the second inductor L2-j can be increased to greatly increase the inductance component. In order to move from the second coordinate ② to the third coordinate ③, it is necessary to move in the downward direction of the concentric circles on the Smith chart, so it is necessary to increase the capacitance component. For example, as described above, the separation distance of the wire constituting the second inductor L2-j can be increased to greatly increase the capacitance component. However, it is not limited to this example, and the number of wires constituting the second inductor L2-j, the thickness of the wire, the length of the wire, and the spacing between adjacent wires can be comprehensively changed to match the first coordinate ① with the third coordinate ③.

[0076] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by a person of ordinary skill in the art to which the present invention pertains belong to the scope of the present invention.

Claims

1. A battery system, comprising at least one battery module, wherein the at least one battery module comprises a battery cell configuration unit and a slave battery management system BMS for managing the battery cell configuration unit, wherein the battery system comprises: the communication unit of the slave BMS; a capacitor connected between the communication unit and a first ground; a first inductor and a second inductor, the first inductor and the second inductor being connected in series between a contact portion between the first ground and the capacitor and a second ground; as well as a control unit that transmits an AC signal having a predetermined frequency to the communication unit in the antenna mode for communicating from the BMS to the outside, Wherein, the second inductor The conductive wires are configured so that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS as a communication target.

2. The battery system according to claim 1, wherein: For the second inductor, At least one of the number of conductive lines, the thickness of the conductive lines, the length of the conductive lines, and the spacing between adjacent conductive lines is determined so that the first antenna impedance and the second antenna impedance are matched.

3. The battery system according to claim 2, wherein: The first inductor and the second inductor Located between the battery cell configuration unit and the slave BMS.

4. The battery system according to claim 3, wherein: The length between the second inductor, which is farther from the contact portion than the first inductor, and the first ground Corresponding to 1 / 4 of the wavelength of the AC signal.

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

6. The battery system according to claim 5, further comprising: A monitoring unit is electrically connected to each of the plurality of battery cells included in the battery cell configuration unit and collects battery data including at least one of a current, a voltage, and a temperature of each of the plurality of battery cells.

7. The battery system according to claim 6, wherein: The control unit A direct current signal is sent 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 manages at least one slave BMS by wirelessly communicating with the communication unit.

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

10. The battery system according to claim 1, wherein: The first inductor It is configured in the form of a chip with a preset impedance value.

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