Battery system

Abstract

The present invention relates to a battery system capable of wireless communication between a plurality of battery management systems (BMS). A battery system includes at least one battery module including a battery cell configuration unit and a slave BMS for managing the battery cell configuration unit, and 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 between the first ground and the capacitor and a second ground; and a control unit for transmitting 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, wherein the second inductor is composed of a wire so that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS which is to be communicated with.

Description

battery system

[0001] Cross-citation with related application(s)

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

[0003] The present invention relates to a battery system capable of wireless communication between a plurality of battery management systems (BMS).

[0004] A battery system applied to an electric vehicle, etc., 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. In addition, the battery system may further include a master battery management system (BMS) that communicates with the vehicle system and manages a plurality of battery modules.

[0005] Recently, research and development on wireless communication between a master BMS and multiple slave BMSs has been increasing to solve problems such as poor quality of electrical wiring related to wire cables and connectors, frequent maintenance issues, and to increase the driving range of electric vehicles by reducing the weight.

[0006] The present invention provides a battery system capable of wireless communication between a plurality of BMS (Battery Management Systems) without adding separate components for wireless communication.

[0007] The present invention provides a battery system capable of impedance matching of an antenna with a simple configuration.

[0008] The present invention provides a battery system capable of wireless communication between a plurality of BMS (Battery Management Systems) in various ISM (Industrial Scientific and Medical) bands.

[0009] According to one aspect of the present invention, a battery system comprises at least one battery module including a battery cell configuration unit and a slave BMS (Battery Management System) for managing the battery cell configuration unit, wherein the battery system comprises 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 between the first ground and the capacitor and a second ground, and a control unit for transmitting an AC signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with the outside, wherein the second inductor is configured with a wire such that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS that is a communication target.

[0010] The second inductor may be configured such that 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.

[0011] The first inductor and the second inductor may be positioned between the battery cell component and the slave BMS.

[0012] The length between the second inductor, which is located further from the contact point than the first inductor, and the first ground may correspond to 1 / 4 of the wavelength of the AC signal.

[0013] 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.

[0014] The above battery system may further include a monitoring unit that 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 current, voltage, and temperature of each of the plurality of battery cells.

[0015] The control unit can transmit a direct current signal to the communication unit in a monitoring mode in which the monitoring unit collects the battery data.

[0016] The above battery system may further include a master BMS that manages at least one slave BMS by wirelessly communicating with the communication unit.

[0017] The control unit can transmit the collected battery data to the master BMS through the communication unit in the antenna mode.

[0018] The above first inductor can be configured in the form of a chip having a preset impedance value.

[0019] The present invention enables wireless communication and impedance matching of an antenna with a simple configuration, thereby reducing the size of a PCB (Printed Circuit Board) constituting a slave BMS and reducing costs.

[0020] The present invention enables a commonization design of the BMS PCB, since the BMS PCB does not need to be changed according to the frequency band.

[0021] FIG. 1 is a block diagram illustrating a battery system according to one embodiment.

[0022] Figure 2 is a block diagram illustrating in detail the battery module of Figure 1.

[0023] Figure 3 is a block diagram detailing when the battery module of Figure 1 operates in monitoring mode.

[0024] FIG. 4 is a block diagram detailing when the battery module of FIG. 1 operates in antenna mode.

[0025] Figure 5 is a block diagram illustrating the antenna of Figure 4 in detail.

[0026] FIG. 6 is an example diagram of a Smith Chart for explaining antenna matching according to one embodiment.

[0027] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the attached drawings. The same or similar components will be given the same or similar drawing reference numerals, and redundant descriptions thereof will be omitted. The suffixes "module" and / or "part" used for components in the following description are given or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

[0028] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0029] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0030] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0031]

[0032] FIG. 1 is a block diagram illustrating a battery system according to one embodiment, and FIG. 2 is a block diagram illustrating in detail the battery module of FIG. 1.

[0033] Referring to FIG. 1, the battery system (1) includes a battery (10) and a master BMS (Battery Management System, hereinafter referred to as master BMS) (20).

[0034] The battery (10) includes at least one battery module. In FIG. 1, a plurality of battery modules (10_1-10_n) are illustrated, but the present invention is not limited thereto, and the battery (10) may include one battery module (10_1).

[0035] Hereinafter, when designating a specific battery module among a plurality of battery modules (10_1-10_n), the drawing symbol “10_j” is used, and the battery cell components and slave BMS included in the battery module (10_j) are each indicated by the drawing symbols “100j” and “200j.” In addition, the capacitors, inductors, contacts, and antennas included in the battery module (10_j) described below are each indicated by the drawing symbols “Cj,” “Lj,” “Nj,” and “200_Aj.”

[0036] The battery module (10_j) includes a battery cell component (100j) and a slave BMS (200j).

[0037] The battery cell component (100j) 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. While FIGS. 1 and 2 illustrate a battery cell component (100j) including three battery cells (Cell1, Cell2, Cell3) connected in series, the battery cell component (100j) is not limited thereto. The battery cell component (100j) may include a variety of battery cells.

[0038] The slave BMS (200j) can collect battery data for the battery cell component (100j) and transmit the collected battery data to the master BMS (20) via wireless communication. 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, Cell3). In addition, the battery data can include at least one of the module voltage, which is the voltage across the two ends of the battery cell component (100j), and the module current, which is the current flowing in the battery cell component (100j).

[0039] 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).

[0040] The monitoring unit (210j) is electrically connected to a plurality of battery cells (Cell1, Cell2, Cell3) and collects battery data. For example, the monitoring unit (210j) may be configured as an IC (Integrated Circuit) capable of collecting battery data, such as an ASIC (Application Specific IC), a BMIC (Battery Monitoring IC), etc.

[0041] Referring to FIG. 2, for example, the monitoring unit (210j) is electrically connected to the positive and negative poles of each of the plurality of battery cells (Cell1, Cell2, Cell3) and measures the cell voltage of each of the plurality of battery cells (Cell1, Cell2, Cell3). For another example, the monitoring unit (210j) may receive information about the cell current and cell temperature measured by each of a current sensor (not shown) and a temperature sensor (not shown). For another example, the monitoring unit (210j) may measure the cell voltage of each of the plurality of battery cells (Cell1, Cell2, Cell3) at predetermined intervals during a rest period in which no charging or discharging occurs, and may calculate the cell current based on the measured cell voltage. 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).

[0042] The communication unit (220j) may be an analog signal processing device that processes data requiring transmission. For example, the communication unit (220j) may be configured as an RFIC (Radio Frequency IC), but is not limited thereto.

[0043] According to an embodiment, the control unit (230j) may convert a digital signal into an analog signal (AC signal) and transmit it to the communication unit (220j). Then, the communication unit (220j) 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 will be provided with reference to FIGS. 4 and 5 below.

[0044] The control unit (230j) can control the overall operation of the slave BMS (200j). For example, it can control the monitoring unit (210j) to collect battery data and control the communication unit (220j) to transmit the collected battery data to the master BMS (20).

[0045] A capacitor (Cj) may be connected between the communication unit (220j) and the first ground (GND1-j). At this time, 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 an earth ground or a chassis ground.

[0046] The first inductor (L1-j) and the second inductor (L2-j) may be connected between the contact point (Nj) between the first ground (GND1-j) and the capacitor (Cj) and the second ground (GND2-j). For example, when the battery cell component (100j) and the slave BMS (200j) are connected with 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 component (100j) and the slave BMS (200j) are connected with a wire, the first inductor (L1-j) and the second inductor (L2-j) may be formed on the wire.

[0047] According to an embodiment, referring to FIG. 2, 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). 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 component (100j). At this time, the second ground (GND2-j) may be a chassis ground located in the battery cell component (100j), but is not limited thereto. For example, the second ground (GND2-j) can be implemented as an earth ground or a signal ground.

[0048] 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 a battery cell component (100j) and a slave BMS (200j) using surface mount technology (SMT). Surface mount technology (SMT) is a technology that prints solder paste on an FPCB substrate and mounts chip components thereon using reflow to bond the FPCB and the chip components.

[0049] According to an embodiment, the first inductor (L1-j) configured in the form of a chip may be standardized at predetermined size intervals, such as 30H, 50H, 100H, etc. That is, although the first inductor (L1-j) has a large inductance, there may be a limitation that makes it difficult to precisely tune the impedance.

[0050] The second inductor (L2-j) may be composed of wires. In some embodiments, the second inductor (L2-j) may be small in size but may be capable of precise impedance tuning. For example, when the number of wires constituting the second inductor (L2-j) increases, the size 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 size of the resistance (R) may decrease. In addition, when the material of the wire constituting the second inductor (L2-j) is changed, 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 size of the inductance (L) may increase. Additionally, as the spacing between the plurality of wires constituting the second inductor (L2-j) increases, the capacitance (C) value may increase. A specific method for tuning the impedance by changing the number, thickness, material, and length of the wires constituting the second inductor (L2-j) is described below together with FIG. 6.

[0051] The master BMS (20) can wirelessly communicate with each of the multiple slave BMSs to transmit various control signals or receive battery data. According to the embodiment, the slave BMS (200j) 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.

[0052]

[0053] FIG. 3 is a block diagram explaining in detail when the battery module of FIG. 1 operates in monitoring mode, FIG. 4 is a block diagram explaining in detail when the battery module of FIG. 1 operates in antenna mode, and FIG. 5 is a block diagram explaining in detail the antenna of FIG. 4.

[0054] According to an 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. Below, FIG. 3 details the structure of the battery module (10_j) in the monitoring mode, and FIGS. 4 and 5 detail the structure of the battery module (10_j) in the antenna mode.

[0055] Referring to FIG. 3, in the monitoring mode, the control unit (230j) can control the communication unit (220j) to transmit a direct current signal (DC signal) to the capacitor (Cj).

[0056] When a direct current (DC) signal is applied to a capacitor (Cj), a circuit as shown in Fig. 3 can be formed depending on the electrical characteristics of the capacitor (Cj) that is opened by the DC signal. 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). At this time, external noise can be removed by the first inductor (L1-j) and the second inductor (L2-j).

[0057] Referring to FIG. 4, in antenna mode, the control unit (230j) can control the communication unit (220j) to transmit an AC signal having a predetermined frequency to the capacitor (Cj).

[0058] When an alternating current (AC) signal is applied to a capacitor (Cj), a circuit such as that shown in Fig. 4 can be formed depending on the electrical characteristics of the first inductor (L1-j) and the second inductor (L2-j) that are opened by the AC signal.

[0059] Even if the AC signal passes through the first inductor (L1-j), the area after the first inductor (L1-j) is not completely open, and some of the AC signal remains. Then, when the AC signal passes through the second inductor (L2-j), almost no AC signal remains. In Fig. 5, the darker the color, the stronger the RF AC signal component can be, and the second inductor (L2-j) can also function as an antenna.

[0060] Specifically, a transmission line (bold portion) connecting a first terminal connected to a capacitor (Cj), a second terminal connected to a first ground (GND1-j), and a third terminal adjacent to a second inductor (L2-j) can perform an inverted-F antenna function. 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).

[0061] The inverted-F antenna is an antenna designed to improve the impedance matching of an inverted-L antenna. The inverted-L antenna may be an antenna that is made by horizontally bending approximately 80% of the upper length of a monopole antenna to reduce its height.

[0062] Referring to FIG. 4, for example, the antenna (Ant-j) can 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) can receive an electromagnetic wave, convert the received electromagnetic wave into an AC signal, and transmit the converted AC signal to the communication unit (220j).

[0063] In some embodiments, the antenna (Ant-j) may resonate at a frequency having a wavelength (λ) that is four times the antenna length (AL). Specifically, the inverted-F antenna may be configured with an antenna length (AL=λ / 4) that corresponds to 1 / 4 of the wavelength (λ) of a 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).

[0064] For example, in order 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. In another example, in order 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.

[0065] In some embodiments, the antenna length (AL-j) may be determined based on the positions (mounting distances) of the first inductor (L1-j) and the second inductor (L2-j). That is, by a simple operation of changing the positions at which the first inductor (L1-j) and the second inductor (L2-j) are mounted, the slave BMS (200j) can wirelessly communicate with the master BMS (20) in various ISM (Industrial Scientific and Medical) frequency bands.

[0066]

[0067] FIG. 6 is an example diagram of a Smith Chart for explaining antenna matching according to one embodiment.

[0068] In antenna systems, impedance mismatch can result in reflected waves, resulting in power loss. Therefore, impedance matching is essential when connecting two circuits, such as a signal source and a load, to prevent reflection loss. Impedance matching of sensitive receiver components can improve the signal-to-noise ratio (SNR) and linearize frequency characteristics.

[0069] In some embodiments, in wireless communication between a slave BMS (200j) and a master BMS (20), one side may be a signal source and the other side may be a load. For convenience of explanation, impedance matching, which matches the impedance of the slave BMS (200j) to the impedance of the master BMS (20), is described below. That is, in the following, the impedance of the slave BMS (200j) is referred to as the load impedance, and the impedance of the master BMS (20) is referred to as the signal source impedance.

[0070] Figure 6 is an example of a Smith chart, which may be a superimposed form of an impedance chart and an admittance chart. Since the impedance chart and admittance chart are both well-known, their drawing and description are omitted. Depending on the embodiment, impedance matching can be explained using the Smith chart.

[0071] In an embodiment, when the second inductor (L2-j) is varied for impedance matching using a Smith chart, when the inductance component increases, it moves along the upward direction of the concentric circles of the Smith chart, and when the capacitance component increases, it moves along the downward direction of the concentric circles of the Smith chart.

[0072] When only the first inductor (L1-j) in the form of a standardized chip is mounted, an impedance mismatch, i.e., a deviation, may occur between the master BMS (20) and the slave BMS (200j). For example, in Fig. 6, let us assume that the first coordinate (①) is the load impedance corresponding to the slave BMS (200j) when only the first inductor (L1-j) is mounted, 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) is changed, 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 embodiment, impedance matching can be realized by performing impedance tuning using the second inductor (L2-j) after mounting the first inductor (L1-j). The user can select various trajectories of the Smith chart to move the first coordinate (①) to the target point, the third coordinate (③). For example, in Fig. 6, it is assumed that after moving from the first coordinate (①) to the second coordinate (②), the movement is made from the second coordinate (②) to the target coordinate, the third coordinate (③).

[0075] Referring to Fig. 6, in order to move from the first coordinate (①) to the second coordinate (②), it is necessary to move in an upward concentric direction on the Smith chart, and thus an increase in the inductance component is required. For example, as previously explained, the inductance component can be greatly increased by increasing the length of the wire constituting the second inductor (L2-j). In order to move from the second coordinate (②) to the third coordinate (③), it is necessary to move in a downward concentric direction on the Smith chart, and thus an increase in the capacitance component is required. For example, as previously explained, the capacitance component can be greatly increased by increasing the separation distance between the wires constituting the second inductor (L2-j). However, the present invention is not limited to these examples, and the first coordinate (①) can be matched with the third coordinate (③) by comprehensively changing the number of wires constituting the second inductor (L2-j), the thickness of the wires, the length of the wires, and the spacing between adjacent wires.

[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 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 (Battery Management System) for managing the battery cell component, The communication unit of the above slave BMS, A capacitor connected between the above communication unit and the first ground, A first inductor and a second inductor connected in series between the contact point between the first ground and the capacitor and the second ground, and In the antenna mode in which the slave BMS communicates with the outside, the control unit is provided to transmit an AC signal having a predetermined frequency to the communication unit, The above second inductor, A battery system configured with a wire so that the first antenna impedance determined by the first inductor matches the second antenna impedance of the master BMS that is the communication target.

2. In paragraph 1, The above second inductor, A battery system in which 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. In paragraph 2, The above first inductor and second inductor, A battery system located between the above battery cell component and the slave BMS.

4. In paragraph 3, The length between the second inductor, which is located further from the contact point than the first inductor, and the first ground is A battery system corresponding to 1 / 4 of the wavelength of the above AC signal.

5. In paragraph 1, The above first ground is the signal ground of the slave BMS, The above second ground is a chassis ground of the battery cell component, a battery system.

6. In paragraph 5, A battery system further comprising a monitoring unit electrically connected to each of a 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.

7. In paragraph 6, The above control unit, A battery system in which the monitoring unit transmits a direct current signal to the communication unit in a monitoring mode in which the battery data is collected.

8. In paragraph 7, A battery system further comprising a master BMS that manages at least one slave BMS by wirelessly communicating with the communication unit.

9. In paragraph 8, The above control unit, A battery system that transmits the collected battery data to the master BMS through the communication unit in the above antenna mode.

10. In paragraph 1, The above first inductor, A battery system configured in the form of a chip having a preset impedance value.

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