Improved communication device for battery packs
Patent Information
- Application Number
- JP2025530772
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-11-29
- Filing Date
- 2023-05-26
- Publication Date
- 2025-11-28
Smart Images
Figure 2025538663000001_ABST
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to the field of batteries and battery cells. Embodiments of the present disclosure relate to an assembly for use with a battery pack including a plurality of battery cells, the assembly enabling wireless communication between an electronic device in the battery pack and a battery management system (BMS) including a wireless transceiver located remotely from the electronic device. [Background technology]
[0002] Battery systems including multiple battery cells are used in a wide range of modern power applications. For example, they are used to power electric vehicles, industrial power applications, transportation, and commercial applications such as powering modern electronic devices. Given the relatively high power demands of such applications, battery systems often include multiple battery cells coupled together to achieve a required power output and / or voltage output. Battery cells may be coupled together to form a battery pack, and a battery system may include one or more battery packs.
[0003] It is common for battery systems to be connected to a battery management system (BMS) configured to ensure that the battery system operates within its safe operating range. The safe operating range is defined as the temperature, voltage, and current conditions under which the battery system is expected to operate without self-damage. The BMS may include one or more cell monitoring devices (CMDs) configured to monitor at least one battery cell and report back to the BMS. A CMD typically consists of an electronic device that may be configured to measure physical characteristics at the battery cell level, such as current, voltage, temperature, and other characteristics useful in determining the state of the battery cell.
[0004] As a result, a BMS typically includes a means of communication between each CMD and the BMS's management circuitry. However, given the high-voltage environment in which the BMS and CMD are deployed, it is essential that such systems provide high-voltage isolation and EMI (electromagnetic interference) immunity performance to ensure fault-free operation. High-voltage isolation is necessary for communication signals transmitted between individual battery cells or packs and the BMS because each battery cell or pack is at a different voltage relative to the system ground. Voltage fluctuations from the system ground can reach hundreds of volts in a typical battery system. Thus, kilovolts of isolation may be required. Furthermore, electromagnetic interference can couple with the communication signals transmitted between the CMD and the BMS, disrupting or directly interfering with the communication signals. Because high-voltage battery systems are a powerful source of EMI, the immunity performance of the communication system deployed within the battery pack is important.
[0005] Known applications for signal communication within a battery system include isolated wired communication protocols such as CAN bus, or wireless communication protocols such as WiFi or ZigBee. While both approaches address the isolation issue, wired communication protocols do not directly address EMI issues and require more cumbersome assembly. The use of WiFi or ZigBee, which involves the use of far-field communication protocols, requires that each antenna within the battery system be separated by multiple wavelengths at which radio frequencies operate in order to function optimally. These solutions may not fit within the typical dimensions of many battery systems.
[0006] It is an object of at least some embodiments of the present disclosure to address one or more of the shortcomings of the prior art and, in particular, to provide a more convenient means for enabling communication with a BMS within a battery system that benefits from high voltage isolation and electromagnetic interference immunity. Summary of the Invention
[0007] According to one aspect of the present disclosure, there is provided an assembly for use with a battery pack including a plurality of battery cells, the assembly being suitable for enabling communication between an electronic device and a wireless transceiver located remotely from the electronic device. The assembly may include: a module antenna operably connected to the electronic device, the module antenna including first and second coils that are conductors; and a bus antenna configured to provide a communication channel for the wireless transceiver, the bus antenna including two transmission lines, each transmission line spaced apart from and adjacent to the first and second coils, respectively, to enable short-range coupling between the module antenna and the bus antenna when a transmission signal is input to either the module antenna or the bus antenna. The two transmission lines are positioned relative to the coils such that the magnitude of the current induced in each transmission line by coupling between each transmission line and the adjacent coil is substantially equal.
[0008] According to other aspects of the present disclosure, there is provided a battery cell including the aforementioned assembly, and a battery pack having a plurality of battery cells including the aforementioned assembly.
[0009] Particular embodiments of the present disclosure are described in more detail below with reference to the accompanying drawings, in which like-numbered reference numerals appearing in different drawings refer to the same components and / or steps, and in which the drawings are not drawn to scale. [Brief explanation of the drawings]
[0010] [Figure 1] FIG. 1 is a schematic diagram of a battery system according to an embodiment of the present disclosure. [Figure 2A] FIG. 1 is a schematic diagram of an exemplary balanced circuit employing common mode rejection. [Figure 2B] FIG. 2B is a schematic diagram of the balanced circuit of FIG. 2A including a balun. [Figure 3]1 is a schematic diagram of an exemplary bus / module antenna assembly, according to one embodiment of the present disclosure. [Figure 4A] 1 is a schematic diagram of a counterclockwise magnetic field generated by an elongated conductor carrying a current. [Figure 4B] 1 is a schematic diagram of a counterclockwise magnetic field generated by an elongated conductor carrying a current. [Figure 5A] 1 is a schematic diagram of a magnetic field generated by a current carrying coil, with current flowing through the coil from left to right. [Figure 5B] 1 is a schematic diagram of a magnetic field generated by a current carrying coil, with current flowing through the coil from right to left. [Figure 6A] 1 is a schematic diagram of inductive magnetic coupling between a coil and an elongated conductor when current is flowing through the elongated conductor in a direction out of the page. [Figure 6B] 1 is a schematic diagram of inductive magnetic coupling between a coil and an elongated conductor when current flows through the elongated conductor into the page. [Figure 6C] 1 is a schematic diagram of inductive magnetic coupling between a coil and an elongated conductor when current flows through the coil from right to left. [Figure 6C] 1 is a schematic diagram of inductive magnetic coupling between a coil and an elongated conductor when current flows through the coil from left to right. [Figure 7A] FIG. 1 is a schematic diagram of an exemplary bus / module antenna assembly in operation in a configuration where the coils are connected at a T-junction, in accordance with one embodiment of the present disclosure. [Figure 7B] FIG. 7B is a schematic diagram of the exemplary bus / module antenna assembly shown in FIG. 7A in a configuration in which the coils are connected in series, according to one embodiment of the present disclosure. [Figure 7C] FIG. 7C is a schematic diagram of the exemplary bus / module antenna assembly shown in FIG. 7B in a configuration in which the coils are connected in series, in accordance with another embodiment of the present disclosure. [Figure 7D]FIG. 1 is a schematic diagram of an exemplary bus / module antenna assembly in a configuration where the coils are connected at a T-junction and the conductors of the bus antenna are located on opposite sides of the coil, in accordance with one embodiment of the present disclosure. [Figure 7E] FIG. 7E is a schematic diagram of the exemplary bus / module antenna assembly shown in FIG. 7D in a configuration in which the coils are connected in series, in accordance with an embodiment of the present disclosure. [Figure 7F] FIG. 7F is a schematic diagram of the exemplary bus / module antenna assembly shown in FIG. 7E in a configuration in which the coils are connected in series, in accordance with another embodiment of the present disclosure. [Figure 8] 1 is a schematic diagram of an exemplary bus / module antenna assembly in which a differential pair of signals is output to a coil, according to one embodiment of the present disclosure. FIG. [Figure 9A] FIG. 1 is a schematic diagram of an exemplary bus / module antenna assembly in a configuration in which the coil is included in a printed wiring board circuit arranged orthogonally to the plane of the bus antenna, according to one embodiment of the present disclosure. [Figure 9B] FIG. 2 is a schematic diagram of an exemplary bus / module antenna assembly in a configuration in which the coil is included in a circuit on a printed wiring board arranged parallel to the plane of the bus antenna, according to one embodiment of the present disclosure. [Figure 9C] 9 is a schematic diagram illustrating the embodiment of FIG. 8 implemented with a printed wiring board arranged orthogonal to the plane of the bus antenna. [Figure 9D] 10 is a schematic diagram illustrating the embodiment of FIG. 9 implemented by a printed wiring board arranged parallel to the plane of the bus antenna. [Figure 10] FIG. 1 is a perspective view of an exemplary battery system including multiple battery cells, each including a PCB with a module antenna mounted thereon, with the bus antenna positioned orthogonal to the plane of the battery cell including the PCB. DETAILED DESCRIPTION OF THE INVENTION
[0011] Exemplary embodiments of the present disclosure will now be described with reference to the accompanying drawings. The same reference numbers used in different drawings represent the same or similar elements unless otherwise stated. The exemplary embodiments described below do not represent all possible implementations of the present disclosure. Rather, they are merely non-limiting examples consistent with aspects of the present disclosure as set forth in the appended claims.
[0012] Embodiments of the present disclosure provide an assembly including an electronic device and a module antenna, configured locally with a battery module, that enables wireless short-range communication with a bus antenna. The bus antenna provides a signal path from the battery module to a remotely located battery management system (BMS). The short-range communication with the bus antenna is achieved through electromagnetic coupling between the module antenna and the bus antenna. The module antenna itself may include one or more coils, thereby enabling electromagnetic coupling with the bus antenna through a wide range of orientations of the bus antenna relative to the module antenna coil. Thus, embodiments of the present disclosure provide a convenient solution for achieving short-range communication within a battery system, which can accommodate a variety of battery module placement orientations within the battery system. Further details follow below, along with a description of the basic operating principles.
[0013] Overview of Battery Management Systems (BMS). FIG. 1 is a schematic diagram of a battery system 100 according to an embodiment of the present disclosure. The battery system 100 includes, but is not limited to, a plurality of battery modules 103 (labeled with an integer between 1 and N, where N is the total number of battery modules in the battery system 100), a BMS 101, one or more cell monitoring devices (CMDs) 105, and a bus antenna 115. According to the illustrated embodiment, each battery module 103 is monitored by an associated CMD 105 (labeled with an integer related to the associated battery module). In alternative embodiments, each single CMD may monitor one or more different battery modules. The battery modules 103 of the battery system 100 may be electrically coupled, and the battery system 100 may include electrical terminals 119 for drawing power from the battery system 100. The battery module 103 may include a single battery cell or multiple battery cells arranged in series, parallel, or a combination thereof. 1, each CMD 105 may be configured to communicate (transmit / receive data) with the BMS 101, and more specifically, with the BMS management circuitry 113, by near field coupling (NFC) with a bus antenna 115. The bus antenna 115 may be connected to a wireless transceiver 111, which is itself connected to the management circuitry 113 of the BMS 101.
[0014] Each CMD 105 may include an electronic device 107 and a module antenna 109. The electronic device 107 may include or be operatively connected to a plurality of sensors configured to measure and monitor one or more physical characteristics (e.g., voltage, current, charge, temperature, pressure, humidity) at the battery module or battery cell level. The module antenna 109 may be associated with any physical system capable of establishing NFC communication with the bus antenna 115. Thus, the module antenna 109 and the bus antenna 115 enable communication between each electronic device 107 of each CMD 105 and a wireless transceiver 111 located remotely from the plurality of electronic devices 107.
[0015] In this context, short-range coupling may be interpreted to include a separation distance between the bus antenna 115 and each module antenna 109 that is less than one wavelength of electromagnetic radiation, or more specifically, less than one wavelength of the wireless transmission signal between the bus antenna 115 and the module antenna 109. For example, if the wavelength is 120 mm, the separation distance may be less than 120 mm. Stronger electromagnetic short-range coupling may occur if the separation is substantially shorter than one wavelength, e.g., less than one-tenth of a wavelength. The battery system 100 may be configured such that each module antenna 109 is no more than one-half, one-third, one-quarter, one-fifth, one-sixth, one-seventh, one-eighth, one-ninth, or one-tenth of a wavelength of electromagnetic radiation from the transmission line. According to some embodiments, the wavelength of the transmission signal may be associated with any Industrial, Scientific, Medical (ISM) short-range wireless band. Exemplary, non-limiting wavelengths may include 440 MHz, 828 MHz, 915 MHz, 2.4-2.5 GHz, and 5 GHz.
[0016] The use of near-field coupling may allow multiple module antennas 109 to be located closer to the bus antenna 115, making the module antennas 109 less susceptible to external EMI interference than prior art long-field module antennas, thereby overcoming some of the problems noted above. According to some embodiments, multiple module antennas 109 may be located at substantially the same distance from the bus antenna 115. Transmission of communications between the electronic device 107 and the wireless transceiver 111 may be subject to additional constraints resulting from the high-voltage environment of the battery system 100. As previously mentioned, these additional constraints relate to high-voltage isolation and immunity to electromagnetic interference. These two constraints are discussed below.
[0017] High voltage insulation Battery system operating voltage (V B ) are obtained by stacking different cells or battery packs in series (as shown in Figure 1). In most applications, these operating voltages are called high voltages (V B>60V). For example, automotive batteries typically have an operating voltage of about 400V, a bus may operate at 800V, and an industrial energy storage system may operate at 1500V. As shown in FIG. 1, each battery module 103 has a different voltage / potential difference V with respect to the ground of the battery system 100. i+1 -V i (where i is an integer between 1 and N), igradually increases. The last battery module 103-N in the battery system 100 will be at a higher voltage than the first battery module 103-1. It may be necessary to insulate these high voltages to prevent devices in the battery system from being exposed to them, which may otherwise be unable to withstand them. In particular, high-voltage isolation is required between the antenna module 109 and the bus antenna 115. In FIG. 1, the module antenna 109 and the bus antenna 115 are separated by gaps 2, 4, 6, and 8. From the preceding discussion regarding the voltages experienced by each different battery module 103, the high-voltage isolation required across gaps 2, 4, 6, and 8 may, in principle, be different for different battery modules 103 depending on the voltages each battery module 103 is exposed to. Thus, for example, the high-voltage isolation required across gap 2 between the module antenna 109 and bus antenna 115 of battery module 103-1 may be lower than the high-voltage isolation required across gap 8 between the module antenna 109 and bus antenna 115 of battery module 103-N. This is because battery module 103-N may be at a higher voltage compared to battery module 103-1. Accordingly, battery systems 100 are envisioned in which different battery modules have different high-voltage isolations. However, for practical purposes, it is often easier to configure each battery module 103, its associated module antenna 109, and gaps 2, 4, 6, and 8 to meet the maximum high-voltage isolation that may be experienced within battery system 100. In other words, each battery module, and more specifically, its associated module antenna 109 and gaps 2, 4, 6, and 8, may be configured to ensure high-voltage isolation for the maximum voltage that battery module 103-N may be experienced.
[0018] Consider a car battery consisting of 96 lithium polymer cells with a maximum voltage of 4.2 V. The maximum operating voltage of such a car battery, V Bis therefore 403.2 V. A car battery may be divided into eight battery modules of 12 series-connected cells, each at a voltage of 50.4 V. A CMD configured to handle 60 V can therefore monitor 12 cells, but because the battery pack is connected in series, each subsequent CMD must be electrically isolated from all other CMDs and associated battery modules, particularly the car battery operating voltage V to ensure that the maximum potential difference seen by any single CMD is less than 60 V. B If the two battery packs are not completely isolated, their respective CMDs may not be able to withstand the potential difference (100.8V).
[0019] High-voltage insulation not only requires the use of the correct insulating components with the right materials, but also the adherence to the correct distances in the design of the battery system to ensure that high-voltage insulation is maintained in all use cases, in all environments, and as the battery system ages. Two characteristic distances related to the geometry of the battery system are crucial to ensure high-voltage insulation: clearance and creepage distance. Clearance (IEC 60664-1) corresponds to the shortest distance in air between two conductive parts, while creepage distance (IEC 60664-1) corresponds to the shortest distance along the surface of a solid insulating material between two conductive parts. To ensure a certain level of voltage insulation between two conductive parts, certain minimum clearance / creepage distances must be observed. These distances are generally specified in industry standard documents, an example of which is IEC standard 60664-1. In practice, the battery operating voltage V B A voltage isolation level greater than 1 kV may be selected, for example, for a 400V battery system, a voltage isolation level of 500V, 1 kV or more may be appropriate.
[0020] It should be noted that high voltages not only represent a risk of damage to battery system components, but also pose a risk of electric shock to battery system assemblers or end users. Components used for signal communication between the CMD, battery modules, and BMS within the battery system are carefully monitored, as they present a potential source of leakage current and the associated risk increases as the number of cells, N, increases.
[0021] Electromagnetic interference immunity and common mode rejection Electromagnetic interference (EMI) is the disturbance of electronic devices or systems due to electromagnetic radiation, electrostatic coupling, magnetic coupling, or electrical conduction. It can cause malfunction, data corruption, data loss, or complete failure of the affected equipment. EMI can be caused by a variety of different sources, including power lines, radio waves, and even household appliances. Within the context of a battery system, the high voltages and currents present are a strong source of EMI, and electronic components such as CMDs or other circuits are susceptible to EMI. Shielding, filtering, and grounding are common methods used to reduce the effects of EMI on electronic systems.
[0022] According to an embodiment of the present disclosure, the approach taken to reduce EMI is the use of balanced electrical paths and common-mode rejection. For an electrical signal to propagate, a return path must exist. In an unbalanced system, a first conductor is provided to propagate the signal, and the return path is referred to as the ground connection. In a balanced system, a second conductor is provided to propagate the same signal as the first conductor, but with opposite polarity (e.g., same amplitude but opposite phase). The second conductor is the return path for the first conductor, and vice versa.
[0023] Balanced systems have two signal propagation modes. The first mode is differential, where the signal of interest is determined by the difference between the signals propagating on the two conductors. The second mode is common, where the signal of interest is the signal that appears on both conductors. In balanced systems, EMI typically couples to the common mode, and noise filtering may be required to eliminate it. In contrast, when operating in differential mode, the signals are of opposite polarity, and the output is determined by calculating the difference between the two opposite-polarity signals propagating on each conductor. When the signal difference is determined, any EMI that couples to the two conductors can be effectively eliminated or filtered. Because the two conductors are located close to each other relative to the distance of the EMI source, the amplitude and polarity of the EMI induced on each conductor are essentially the same. Therefore, when the difference between the two EMI-affected signals propagating in the two conductors is determined, the induced EMI noise cancels out. In this way, the desired signal can be transmitted without leaving any EMI signature on the differential-mode conductors. In practice, a signal subtractor may be required to determine the difference between the two opposite-polarity signals propagating on the two conductors. In other words, the device receives two differential signals as its inputs and outputs their difference, i.e., the signal of interest. A differential receiver may be used to determine the difference. Similarly, a differential amplifier is another example of a signal subtractor, except that it outputs an amplified difference signal. Conversely, generating a differential signal for input onto two conductors may require an input signal splitter and a differential output block, such as an inverter, a differential output amplifier, or a phase splitter. A signal splitter splits the input signal V dm Let us consider two equal amplitude signals V dm The inverter inverts the polarity of one of the divided signals (i.e., -V dm / 2). The end result is that two signals of opposite polarity (i.e., equal amplitude but opposite phase) can be provided and input on separate conductors, thus forming a differential pair of signals. Functionally, a splitter-inverter performs the inverse of a subtractor—given a single input signal, the splitter-inverter splits it into two signals and inverts the polarity of one of them. In contrast, a subtractor is provided with a differential signal pair and determines the difference by subtracting the two differential signals and outputting a difference signal.
[0024] 2A is a schematic diagram of an exemplary balanced circuit using common mode rejection. A signal source 201 receives an input signal V S The circuit includes a first balanced conductor 203-1 and a second balanced conductor 203-2. S / 2 and -V S / 2 is the input signal V S The first differential signal V is generated using the splitter-inverter 207-1. S / 2 is output on the first conductor 203-1, and the second (inverted) differential signal -V S / 2 is output to the second conductor 203-2. If the circuit is not completely immune to EMI, both the first conductor 203-1 and the second conductor 203-2 will receive interference / noise signals V from nearby noise sources 205. ノイズ However, because both conductors are balanced, the resulting signal propagating along the first conductor 203-1 is subject to V ノイズ +V S / 2, and the signal on the second conductor 203-2 is equal to V ノイズ -V S The two resulting signals are input to subtractor 207-2, and a difference signal is output from subtractor 207-2 and input to receiver 209. Thus, receiver 209 measures a signal proportional to the difference between the two signals obtained from first conductor 203-1 and second conductor 203-2, i.e., V ノイズ +V S / 2-V ノイズ -(-V S / 2)=V SCommon mode interference / noise signal V ノイズ As mentioned above, the function of the subtractor 207-2 may be provided by a differential amplifier, in which case the output signal received at the receiver 209 is amplified, i.e., GV S , where G represents the gain of the differential amplifier. A measure of a differential amplifier's ability to reject common-mode voltages is known as the common-mode rejection ratio, or CMRR.
[0025] The differential operation of the first conductor 203-1 signal and the second conductor 203-2 signal can be performed using a balun 208, as shown in FIG. 2B. In other words, according to some embodiments, the functions of the splitter inverter 207-1 and the subtractor 207-2 in FIG. 2A can be provided by the balun 208. The balun 208 is a reciprocal three-port power splitter including one unbalanced port and two balanced ports, shown in FIG. 2B as port 1 and ports 2 and 3, respectively. The signals at the balanced ports are equal and opposite (frequency domain: π phase shift - time domain: one balanced port signal is the opposite of the other balanced port signal). The balun 208 is designed to divide the energy of the signal fed to the unbalanced port equally between the two balanced ports; conversely, the balun can also combine differential signals applied to the two balanced ports at the unbalanced port. In the example shown in FIG. 2B, the balun 208-1 divides the energy of the source signal V applied to the unbalanced port 1 into a S, while balun 208-2 combines the differential signal applied to balanced ports 2 and 3. Receiver 209, which may be associated with a wireless transceiver, typically has only one unbalanced input / output port. To use balanced communication with common-mode rejection, a balun with sufficient CMRR may be required. According to at least some embodiments of the present disclosure, the balun may be associated with a hardware device; however, it should be understood that the functionality provided by a balun may be provided by alternative means. Specifically, as described in the following description of exemplary embodiments, the functionality of balun 208 may be provided by the configuration of module antenna 109 and bus antenna 115 of FIG. 1 . More specifically, applying the principles of FIG. 2B to the battery system of FIG. 1 , when a signal is transmitted from cell monitoring device 105 to BMS 101, electromagnetic coupling of module antenna 109 with bus antenna 115 provides the functionality of balun 208-1 of FIG. 2B , and wireless transceiver 111 provides the functionality of balun 208-2. To achieve this, the wireless transceiver 111 in the BMS 101 may be equipped with a balun or other subtractor device, such as a differential amplifier. Further implementation details according to embodiments of the present disclosure follow below. Alternatively, the bus antenna 115 may be bidirectional, i.e., a transmission signal may be transmitted from any of the CMDs 105 to the BMS 101 or from the BMS 101 to any of the CMDs 105. In this latter situation, the CMD 105 corresponds to the receiver, the wireless transceiver 111 corresponds to the source, and the electromagnetic coupling between the module antenna 109 and the bus antenna 115 provides the function of balun 208-2 in FIG. 2B, while the wireless transceiver 111 provides the function of balun 208-1. To achieve this, the wireless transceiver 111 in the BMS 101 may be equipped with a block that provides a differential output, such as a splitter inverter, a differential output amplifier, or a balun.
[0026] NFC Communication Assembly Returning to FIG. 1 , an embodiment of the present disclosure provides an assembly including a bus antenna 115 and a module antenna 109 employing short-range communication. This assembly enables communication with the BMS 101, specifically, communication between at least one electronic device 107 of each CMD 105 and the wireless transceiver 111 of the BMS 101. Such an assembly simultaneously addresses both high-voltage (HV) isolation and EMI issues. Another advantage of short-range coupling is that the value of the coupling strength can be easily adjusted to achieve weak coupling. The weak coupling may be set so as not to overload the bus antenna 115. The use of weak coupling is advantageous in that it allows a large number of CMDs 105 (e.g., N>200) to be spaced along the bus antenna 115 without overloading it or changing its characteristics. The module antenna 109 may be operatively coupled to the electronic device 107, and the bus antenna 115 may be configured to operatively communicate with the wireless transceiver 111. The module antenna 109 and the bus antenna 115 are positioned relative to one another to enable close-range coupling therebetween when a transmission signal is input to either the module antenna 109 or the bus antenna 115. In other words, the assembly disclosed herein enables bidirectional communication between the CMD 105 and the BMS 101. Within this context, the transmission signal may correspond to an electrical signal characterized by at least one of a voltage, a current, a power, and a frequency of a wavelength. For example, in some non-limiting embodiments, the transmission signal may correspond to a radio wave having a frequency between 2.4 and 2.5 GHz, although as is clear from the foregoing description, this frequency range is in no way limiting. Any desired frequency may be selected, and more specifically, any desired ISM band may be used.
[0027] As shown in FIG. 1 , bus antenna 115 may include at least two transmission lines 115-1 and 115-2. A transmission line may more generally refer to any elongated conductor that enables the transmission of a signal. Accordingly, examples of transmission lines may include a cable, a wire, a cable from a twisted pair, or a microstrip. According to some embodiments, bus antenna 115 may include three or more transmission lines. Accordingly, for purposes of this discussion, the remaining embodiments will be described with respect to a bus antenna having two transmission lines, but it should be understood that the bus antenna may include three or more transmission lines. In such embodiments, it is assumed that one or more additional transmission lines have negligible or no near-field coupling strength (e.g., a ground line) different from module antenna 109. According to some embodiments, bus antenna 115 may also include termination 117 ( FIG. 1 ), which may be located at one end of bus antenna 115 opposite the end to which wireless transceiver 111 (shown in FIG. 1 ) is connected. The bus antenna 115 may be configured such that substantially all of the energy in the transmission lines that is not coupled to the module antenna 109 is absorbed by the termination 117. The termination 117 may include any electrical device configured to match the characteristic impedance of the two transmission lines 115-1 / 2, such as a resistor. According to some embodiments, as described in the previous section, the two transmission lines 115-1 and 115-2 of the bus antenna 115 may be configured as a balanced circuit such that the electrical signal propagating in the first of the two transmission lines is π radians out of phase with the electrical signal propagating in the second of the transmission lines.
[0028] In some embodiments, as described above, module antenna 109 and bus antenna 115 may form an operational balun. In this scenario, the transmission signal may include an unbalanced electrical signal input to module antenna 109, which is output as a balanced electrical signal at bus antenna 115. This is the scenario in which the transmission signal is being transmitted from module antenna 109 to bus antenna 115. Alternatively, if the transmission signal is being transmitted from bus antenna 115 to module antenna 109, the transmission signal may include a balanced electrical signal input to bus antenna 115, which is output as an unbalanced electrical signal at module antenna 109. In this situation, EMI immunity is advantageously enhanced by common-mode rejection.
[0029] Assembly Architecture Having demonstrated the principles of operation of the present disclosure, more specific details regarding the assembly architecture are provided below. FIG. 3 illustrates a schematic diagram of an electromagnetic bus / module antenna assembly consistent with an embodiment of the present disclosure. Specifically, FIG. 3 illustrates how electromagnetic coupling between the module antenna 109 and the bus antenna 115 can be achieved. The module antenna 109 includes a first coil 109-1 and a second coil 109-2, which are conductive. As discussed above, the bus antenna 115 includes at least two transmission lines 115-1 and 115-2. Each transmission line 115-1 and 115-2 is positioned adjacent to and spaced apart from the first coil 109-1 and second coil 109-2 of the module antenna 109, respectively, and is configured to enable near-field coupling when a transmission signal is present in either the bus antenna 115 or the module antenna 109. The two transmission lines 115-1 and 115-2 are arranged with respect to the coils 109-1 and 109-2 so that the induced currents in each transmission line caused by coupling between each transmission line and its adjacent coil are substantially equal. In other words, when a transmission signal is input into the module antenna 109 and also input to the first coil 109-1 and the second coil 109-2, the magnitudes of the induced currents generated in each transmission line 115-1 and 115-2 are substantially equal. In the context of the present disclosure, the coils adjacent to a transmission line may refer to the coils closest to the transmission line. For example, as shown in FIG. 3, the first coil 109-1 is adjacent to the transmission line 115-1, and the second coil 109-2 is adjacent to the transmission line 115-2. Additionally or alternatively, two transmission lines 115-1, 115-2 may be positioned relative to coils 109-1, 109-2 such that the induced currents induced in each of first coil 109-1 and second coil 109-2 by coupling between each transmission line and its adjacent coil are substantially equivalent (transmission signal input to bus antenna 115). Within this context, two substantially equivalent magnitudes may refer to two values whose relative difference is less than a predetermined percentage. For example, two values of induced current may be substantially identical if they differ by less than 1%, 2%, or 5%.Additionally or alternatively, the proximity of the magnitude of the induced currents can be expressed by the CMRR (Common Mode Rejection Ratio), which is described below.
[0030] When the module antenna 109 and the bus antenna 115 form a balun during operation, balanced ports (ports 2 and 3) are formed by the two transmission lines 115-1 and 115-2, which form a balanced circuit. The unbalanced port (port 1) is formed by the electrically connected first coil 109-1 and second coil 109-2. The balance between the two transmission lines 115-1 and 115-2 relates to the assembly's ability to generate induced currents in each transmission line that are phase shifted by π radians but have substantially the same magnitude. The closer the values of the induced currents in each transmission line, the higher the balance and the better the CMRR of the balun formed by the bus antenna 155 and the module antenna 109. For example, according to some embodiments, the balance between the two balanced ports can be configured to provide a CMRR of 0, 10 dB, 20 dB or more, or even higher.
[0031] The unbalanced port (Port 1) may be operatively connected to the electronic device 107. According to some embodiments, the first coil 109-1 and the second coil 109-2 are connected in series or in parallel branches. For example, when connected in parallel, the coils may be connected by a unique node forming a T-junction. The two parallel branches may include one or more electrical components (e.g., capacitors) in addition to the coils 109-1 and 109-2. Thus, the unbalanced port (Port 1) is either located at one of the two ends of the first coil 109-1 and the second coil 109-2 connected in series, or located in a branch at a unique node different from the branch connected to the first coil 109-1 and the second coil 109-2. In the example of FIG. 3, the first coil 109-1 and the second coil 109-2 are connected in series.
[0032] For current to flow through either the first coil 109-1 or the second coil 109-2, the module antenna 109 must be placed in a closed electrical circuit. In the example of FIG. 3, the module antenna 109 and the electronic device 107 form a closed circuit. This closed circuit may include one or more additional electronic components. For example, according to some embodiments, the first coil 109-1 and the second coil 109-2 may be connected to a capacitor 309. As shown in FIG. 3, the capacitor 309 may be connected in series with the first coil 109-1 and the second coil 109-2. Alternatively, the capacitor 309 may be connected in parallel with the first coil 109-1 and the second coil 109-2. The capacitance characteristics of the capacitor 309 may be selected to adjust the resonant frequency of the closed circuit of the module antenna 109.
[0033] The strength of the near-field coupling between the bus antenna 115 and the module antenna 109 is related to the magnitude of the induced current in either the bus antenna 115 or the module antenna 109, as well as the characteristic impedance value and resonant frequency of the circuit of the bus antenna 115 and the module antenna 109. The greater the magnitude of the induced current, the greater the magnitude of the near-field coupling strength.
[0034] The near-field coupling strength, and therefore the magnitude of the induced current in the bus antenna 115 or module antenna 109, depends on the separation distance 303 between each of the bus antenna's transmission lines 115-1, 115-2 and its adjacent coil. Because the near-field coupling strength is expected to increase as the separation distance 303 decreases, the separation distance 303 may be selected to adjust the value of the near-field coupling strength. According to some embodiments, each of the bus antenna's transmission lines 115-1, 115-2 may be positioned equidistant from a different one of the module antenna's coils 109-1, 109-2. For example, as shown in FIG. 3 , the separation distance 303 between the first coil 109-1 and the transmission line 115-1 is substantially equal to the separation distance between the second coil 109-2 and the transmission line 115-2. Notwithstanding the above, alternative embodiments are contemplated in which the separation distances between the bus antenna's transmission lines 115-1, 115-2 and their adjacent coils are different. According to some embodiments, the separation distance 303 between each of the bus antenna transmission lines and its adjacent coils may be selected to achieve a coupling strength of greater than or equal to -50 dB and less than or equal to -10 dB. Alternatively, the separation distance 303 may be selected to achieve a coupling strength of greater than or equal to -40 dB and less than or equal to -20 dB, or greater than or equal to -35 dB and less than or equal to -25 dB. In some embodiments, the coupling strength may be approximately -30 dB.
[0035] The separation distance 303 may also be selected as a function of the clearance / creepage distance 301. A minimum separation distance 303 may be required because a particular clearance / creepage distance 301 is required to ensure a particular level of voltage isolation. The distinction between clearance and creepage distance depends on the nature of the material separating each of the bus antenna's transmission lines and its adjacent coils. According to some embodiments, each of the bus antenna's transmission lines and its adjacent coils may be insulated by a dielectric insulating material. Examples of dielectric insulating materials may include any one or more of air, plastic material, glass-filled plastic material, epoxy composite material, polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polybutylene terephthalate (PBT), polyethylene (PE), polyamide (PA), FR4, ceramic-filled polytetrafluoroethylene (PTFE), ceramic laminate, or Mylar. In the example of Figure 3, the transmission lines 115-1, 115-2 of each bus antenna and their adjacent coils are separated by air. According to some embodiments, the dielectric insulating material may be selected to have a breakdown voltage higher than the operating voltage of the battery system. The breakdown voltage is the voltage at which the dielectric material undergoes a significant increase in its conductivity, resulting in a breakdown of its insulating properties. For example, the operating voltage V of the battery system may be selected to have a breakdown voltage higher than the operating voltage V of the battery system. B is equal to 400 V and the separation distance between each one of the bus antenna transmission lines 115-1, 115-2 and its adjacent coil is 4 mm, a material with a minimum breakdown voltage of 100 V / mm can be used to address the high-voltage insulation problem. In practice, it is common to select a material with a breakdown voltage several orders of magnitude higher than the required breakdown voltage. In the above example, it would be common to select a dielectric material with a breakdown voltage of several kV / mm for increased safety. Examples of such materials are listed above; for example, Mylar has a breakdown voltage equal to 7 kV / mm.
[0036] The first coil 109-1 and the second coil 109-2 have one or more coil characteristics, such as a coil cross-sectional area, a number of conductor turns, an electrical resistance, or a core material. The core material refers to the material on which the coil is wound. For example, in some embodiments, the core material may be at least one of air (air core coil), an insulating material, ferrite, or a ceramic. While this disclosure includes drawings primarily including coils with circular cross-sections, it should be noted that the cross-section of the coil may have any shape (square, rectangular, etc.). According to some embodiments, the first coil 109-1 and the second coil 109-2 may share at least one of the following characteristics: an equivalent coil cross-sectional area, an equivalent number of conductor turns, an equivalent electrical resistance, or an equivalent core material. In the example shown in FIG. 3, the first coil 109-1 and the second coil 109-2 are made from an equivalent conductor, and therefore share an equivalent electrical resistance. Furthermore, they share an equivalent cross-sectional area, an equivalent number of conductor turns (6 turns), and they are both air core coils.
[0037] Similarly, each transmission line 115-1, 115-2 has one or more transmission line characteristics, such as a cross-sectional area, an electrical resistance, or a magnetic permeability. According to some embodiments, the transmission lines 115-1, 115-2 of the bus antenna may share at least one of the following characteristics: a similar cross-sectional area, a similar electrical resistance, or a similar magnetic permeability. For example, as shown in FIG. 3, the transmission lines 115-1 and 115-2 of the two bus antennas are identical, and they both share a similar cross-sectional area, a similar electrical resistance, and a similar magnetic permeability.
[0038] Further, each of the first coil 109-1 and the second coil 109-2 is characterized by a longitudinal axis 305 and a winding direction. According to some embodiments, the first coil 109-1 and the second coil 109-2 may be configured to share the same longitudinal axis 305, as illustrated in the assembly of FIG. 3. It is convenient to orient the longitudinal axis of the coil to characterize the winding direction of the coil. According to some embodiments, the first coil 109-1 and the second coil 109-2 may be wound along the same rotational direction. Alternatively, the first coil 109-1 and the second coil 109-2 may be wound along opposite rotational directions. In the example shown in FIG. 3 , the first coil 109-1 and the second coil 109-2 are wound in opposite directions, with the first coil 109-1 being right-handed about a longitudinal axis 305 and the second coil 109-2 being left-handed about the longitudinal axis 305. Similarly, each of the two transmission lines 115-1, 115-2 is characterized by a longitudinal axis 307. According to some embodiments, the two transmission lines 115-1 and 115-2 may be substantially parallel, i.e., share a common longitudinal axis 307, which, as shown in FIG. 3 , is perpendicular to the plane of the drawing. The alignment of each transmission line 115-1, 115-2 relative to the adjacent coil may be described using the angle between the longitudinal axis 307 of the transmission line and the longitudinal axis 305 of the adjacent coil. This angle may be different for each transmission line 115-1, 115-2. According to some embodiments, for each of the transmission lines 115-1, 115-2 of the bus antenna, the longitudinal axis of the transmission line may be aligned perpendicular to the longitudinal axis of its respective adjacent coil. That is, for both transmission lines, the angle between the longitudinal axis 307 of the transmission line and the longitudinal axis 305 of the adjacent coil may be equal to π / 2.
[0039] Each of the aforementioned parameters (coil / transmission line characteristics, separation distance, and angle between the longitudinal axes of the coil / transmission line) has a direct effect on the value of the induced current generated by the short-range coupling. The effects of these parameters will be explained in the next section, which will provide a detailed description of the inductive magnetic coupling acting between the coil and the transmission line.
[0040] The magnetic field generated by a long, thin conductor carrying an electric current. Magnetic fields arise from electric charges. Figures 4A-4B show different magnetic fields generated by an elongated conductor 401 carrying a current.
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[0041] The magnetic field produced by a coil carrying a current. 5A-5B show a magnetic field generated by a coil 501 through which a current flows.
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[0042] Inductive magnetic coupling. Electromagnetic induction is a phenomenon that occurs when a magnetic field interacts with an electric circuit. Faraday's law of electromagnetic induction states that when a changing magnetic field is applied to a conductor, an electromotive force ε is induced in the conductor, and when the conductor is in a closed circuit, an induced current flows in the conductor. Lenz's law of electromagnetic induction states that the induced current flows in such a way that the magnetic field it produces is opposite to the original changing magnetic field that caused the induction. More specifically, the induced electromotive force ε is the negative rate of change of magnetic flux.
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[0043] Two conductors are said to be inductively or magnetically coupled if a varying current (or supply current I(t)) flowing in one conductor induces a voltage in the other conductor by electromagnetic induction. If the latter conductor forms a closed circuit, a time-varying induced current I ind6A and 6B show the inductive magnetic coupling that occurs between the elongated conductor 601 and the coil 605 when a changing current I(t) flows through the elongated conductor 601. The elongated conductor 601 and the coil 605 are similar to those shown in FIGS. 4A to 5B, and although not shown, both form a closed circuit. When a changing current I(t) flows through the elongated conductor 601, a changing magnetic field
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[0044] 6C and 6D show the inductive magnetic coupling that occurs between the elongated conductor 601 and the coil 605 when a varying current I(t) flows through the coil 605. When a varying current I(t) flows through the coil 605, a varying magnetic field
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[0045] The induced current I in either the elongated conductor 601 or the coil 605 ind The magnitude of (t) depends on the relative arrangement of the elongated conductor 601 and the coil 605, and the characteristic parameters of the elongated conductor or coil, such as the cross-sectional area A, the electrical resistance R, and the magnetic permeability μ. ind (t) is a function of the angle between the unit normal vector of the cross section and the magnetic field, and the strength of the magnetic field B. The latter parameter is particularly related to the distance between the elongated conductor 601 and the coil 605, as the magnetic fields generated by both the elongated conductor 601 and the coil 605 decrease as the distance increases as a function of the distance from the elongated conductor 601 or the coil 605, resulting in a higher induced current value as the gap distance decreases. With respect to the angle α between the unit normal vector of the cross section and the magnetic field, the induced current is at a maximum when the angle α = 0. The angle α is given by
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[0046] Therefore, by appropriately adjusting the various parameters mentioned above, the induced current I indIt should be appreciated that it may be possible to maintain a constant value of I(t). Furthermore, even if the configurations are different or the characteristic parameters are different, given the same supply current I(t), two elongated conductor / coil pairs will produce substantially the same value of induced current I(t). ind For example, if a first elongated conductor / coil pair is spaced apart by a first gap distance and a second elongated conductor / coil pair is spaced apart by a second, larger gap distance, and the first and second elongated conductors carry the same supply current I(t), the second coil may have a larger cross-sectional area, lower electrical resistance, better longitudinal axis orientation, or a core material with higher magnetic permeability, thereby compensating for the decrease in magnetic field strength with increasing gap distance, thereby generating an equal amount of induced current I(t) in both coils. ind (t) can be generated.
[0047] Assembly embodiment As described in the previous section, in each embodiment of the present disclosure, there are multiple configurations of the bus antenna 115 and the module antenna 109, where the induced current in each transmission line of the bus antenna 115 is obtained by coupling between each transmission line and its adjacent coil. The induced current in each transmission line of the bus antenna 115 has substantially the same magnitude. Alternatively, the induced current in each first coil 109-1 and second coil 109-2 of the bus antenna 115 can be obtained by coupling between each transmission line and its adjacent coil. FIGS. 7A-7F illustrate various configurations of bus / module antenna assemblies according to embodiments of the present disclosure. Each illustrated assembly includes a module antenna 109 including a first air core coil 109-1 and a second air core coil 109-2 that share a common longitudinal axis 705. The coils 109-1 and 109-2 have the same circular cross-sectional area, the same number of turns of conductor, and the same electrical resistance. The illustrated bus antenna 115 includes two identical transmission lines 115-1 and 115-2 having the same cross-sectional area, the same electrical resistance, and the same magnetic permeability. Furthermore, each transmission line 115-1 and 115-2 of the bus antenna is positioned equidistantly with respect to the different coils of the module antenna 109. The transmission lines 115-1 and 115-2 of each bus antenna are positioned perpendicular to the longitudinal axis 705 of the adjacent coil. FIGS. 7A-7F show the induced currents I2(t) and I1(t) generated in the first coil 109-1 and the second coil 109-2, respectively, when supply currents I2(t) and I1(t) flow through the transmission lines 115-1 and 115-2, respectively. ind-1 (t) and I ind-2 7A-7F. In some embodiments, the supply currents I1(t) and I2(t) have substantially equal magnitudes but opposite phases. The arrow convention is used to indicate the direction of current in the enclosed diagrams, i.e., I1(t) flows outward from FIGS. 7A-7F and I2(t) flows inward toward FIGS. 7A-7F. Therefore, the transmission line of each bus antenna
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[0048] 7A, the first coil 109-1 and the second coil 109-2 are wound in the same rotational sense (right-handed relative to the longitudinal axis 705) and connected at a unique node 701, forming a T-junction. The first coil 109-1 generates a varying magnetic field that circulates from right to left.
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[0049] 7B, the first coil 109-1 and the second coil 109-2 are wound in the same rotational direction (right-handed relative to the longitudinal axis 703) and connected in series. The first coil 109-1 generates a varying magnetic field that circulates from right to left.
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[0050] 7C, the first coil 109-1 and the second coil 109-2 are wound in opposite directions (the first coil 109-1 is wound right-handed relative to the longitudinal axis 705, and the second coil 109-2 is wound left-handed relative to the longitudinal axis 705) and connected in series. In this configuration, a plane of symmetry 707 exists between the transmission line 115-1 and its adjacent coil 109-1 (first coil), and between the transmission line 115-2 and its adjacent coil 109-2 (second coil). The first coil 109-1 is irradiated with a varying magnetic field that circulates from right to left.
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[0051] 7D-7F show embodiments in which transmission lines 115-1 and 115-2 of bus antenna 115 are located on opposite sides of the coil of module antenna 109. For example, first transmission line 115-1 and second transmission line 115-2 may be located on different parallel planes sandwiching module antenna 109. Further details regarding each embodiment are provided below.
[0052] In the embodiment of Figure 7D, the first coil 109-1 and the second coil 109-2 are wound in opposite directions (first coil 109-1 is wound right-handed and second coil 109-2 is wound left-handed relative to the longitudinal axis 705) and are both connected to a unique node 701. The first coil 109-1 generates a varying magnetic field that circulates from right to left.
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[0053] In the embodiment of Figure 7E, the first coil 109-1 and the second coil 109-2 are wound in the same direction (right-handed with respect to the longitudinal axis 703) and are connected in series. The first coil 109-1 generates a varying magnetic field that circulates from right to left.
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[0054] In the embodiment of Figure 7F, the first coil 109-1 and the second coil 109-2 are wound in opposite rotational directions (first coil 109-1 is wound clockwise relative to longitudinal axis 703, and second coil 109-2 is wound counterclockwise relative to longitudinal axis 703) and are connected in series. The first coil 109-1 generates a varying magnetic field that circulates from right to left.
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[0055] 8 illustrates yet another configuration of the first coil 109-1 and second coil 109-2 and the bus antenna transmission line 115, in which the coil 109 and the bus antenna transmission line 115 are not configured as a balun. Instead, the coil 109 and the bus antenna transmission line are configured as a four-port coupler. In this embodiment, the electronic device 107 is connected to a differential output block that may be associated with a phase splitter 110. When a signal is transmitted from the CMD 105, or more specifically from the module antenna 109 to the bus antenna 115, the phase splitter 110 splits the single input signal V S receives the differential signal V S / 2 and -V S / 2 pair, so that an AC current I(t) flows from the "+" pole to the "-" pole of the phase splitter 110. The second coil 109-2 is wound in the opposite direction to the first coil 109-1. In this way, the magnetic fields in the first coil 109-1 and the second coil 109-2 are oriented in opposite directions. As a result, the induced currents in the first bus antenna transmission line 115-1 and the second bus antenna transmission line 115-2 also flow in opposite directions, forming a differential signal pair. In this embodiment, the first coil 109-1 can be considered as port 1, the second coil 109-2 can be considered as port 2, the first transmission line 115-1 can be considered as port 3, and the second transmission line 115-2 can be considered as port 4. A signal input to port 1 is output at port 3, and a signal input to port 2 is output at port 4. The functionality of phase splitter 110 may be provided by any device that outputs a differential signal pair for a given input signal, such as a balun.
[0056] Printed Circuit Board Assembly According to some embodiments, an assembly including the bus antenna 115 and the module antenna 109 may include a printed circuit board (PCB). In some embodiments, the PCB may include the electronic device 107 and the module antenna 109. In such embodiments, the first coil 109-1 and the second coil 109-2 are included on the PCB. For example, the first coil 109-1 and the second coil 109-2 may be associated with air-core coils or ferrite-core coils soldered to the surface of the PCB. Alternatively, the first coil 109-1 and the second coil 109-2 may be integrated into the PCB substrate. For example, according to some embodiments, the first coil 109-1 and the second coil 109-2 may be formed by multiple tracks and vias. FIGS. 9A-9D show a PCB 901 including the electronic device 107 and the module antenna 109. The first coil 109-1 and the second coil 109-2 may be formed by multiple tracks and vias. The arrangement of the bus antenna 115 and transmission lines 115-1 and 115-2 relative to the first coil 109-1 and second coil 109-2 is similar to that shown in FIG. 7C , with a plane of symmetry 905 extending into the page. Additionally, the coil 109 includes a ground connection 909 and a capacitor 907, ensuring that the coil 109 and electronic device 107 form an unbalanced circuit. The ground connection may be achieved by using a via or track extending from one of the coils to the ground plane of the PCB 901. An advantage of incorporating the module antenna 109 and electronic device 107 on the PCB, as shown in FIGS. 9A-9D , is a smaller footprint compared to embodiments in which the module antenna 109 and electronic device 107 are separately mounted to the battery module. Additionally, incorporating the module antenna 109 and electronic device 107 on the PCB facilitates assembly.Therefore, embodiments in which the module antenna 109 and electronic device 107 are integrated into the PCB make the battery system 100 more compact, reducing the PCB footprint and allowing more battery modules 103 to be stacked within the battery system without increasing volume. The bus antenna 115 can extend in a plane perpendicular to the plane of the PCB 801, as shown in FIG. 9A , or can extend parallel to the plane of the PCB 901, as shown in FIG. 9B . PCB materials can be selected based on required insulation properties. For example, as mentioned above, required clearance and creepage distances can be specified by relevant standards, and thus, PCB materials can be selected to comply with the relevant standards. PCB tracks and / or vias (including vias and / or tracks used to form the coil 109) can be coated with an insulating material to further improve creepage and clearance. Similarly, tracks and / or vias can be embedded within the PCB to further improve creepage and clearance.
[0057] 9C and 9D show an embodiment with the electromagnetic coupling shown in FIG. 8, but where the functionality of phase splitter 110 of FIG. 8 is provided in electronic device 112. For example, electronic device 112 may include local means for replicating the functionality of phase splitter 110. It is envisioned that electronic device 112 may include a phase splitter internally.
[0058] In further embodiments, it is contemplated that the bus antenna transmission line may also be integrated onto the PCB along with the module antennas and electronic devices. In such embodiments, it is contemplated that the PCBs attached to adjacent battery modules are electrically connected, with the bus antenna transmission line forming a continuous electrical path through all of the battery modules in the battery system.
[0059] FIG. 10 is a schematic perspective view of a battery pack 1000 including multiple battery modules 103, each of which has a PCB 901 mounted on its surface. The bus antenna 115, and specifically the first and second transmission lines 115-1 and 115-2, may extend in a plane perpendicular to the surface of the PCB 901 mounted on the battery module 103. The relative configuration of the bus antenna 115 and the module antenna 109 shown in FIG. 10 illustrates one advantage associated with embodiments of the present disclosure, namely, that electromagnetic coupling between the module antenna and the bus antenna can be achieved through various configurations between the bus antenna and the module antenna. Accordingly, the embodiments disclosed herein can be implemented in various types of battery packs, and more specifically, in combination with various relative arrangements of battery modules within the battery pack.
[0060] The description of the examples provided herein is for convenience of explanation. This description is not intended to be exhaustive or to limit the example embodiments to the precise form disclosed; modifications and variations are possible in light of the above teachings or may result from the practice of various alternatives or equivalents to the examples provided. The examples described herein were chosen and described in order to explain the principles and nature of the various example embodiments and, by their practical application, enable those skilled in the art to utilize the example implementations and various modifications in various ways as suited to the particular use intended. Features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, systems, and computer program products. It is understood that the example embodiments presented herein can be implemented in any combination with each other.
[0061] It should be noted that the word "comprising" does not necessarily exclude the presence of other elements or steps than those listed, and that the words "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. Furthermore, it should be noted that any reference signs do not limit the scope of the claims, that the exemplary embodiments may be implemented at least in part by means of both hardware and software, and that several "means," "units," or "devices" may be represented by the same or functionally equivalent items of hardware.
[0062] Various exemplary embodiments described herein are described in the general context of method steps or processes, which, in one aspect, may be implemented by a computer program product embodied in a computer-readable medium or non-transitory computer-readable medium that includes computer-executable instructions, such as program code, executed by a computer or one or more processors in a network environment. The computer-readable medium or non-transitory computer-readable medium may include removable and non-removable storage devices. These storage devices include, but are not limited to, read-only memory (ROM), random access memory (RAM), compact discs (CDs), digital versatile discs (DVDs), flash memory, and the like. Generally, program modules may include routines, programs, objects, components, data structures, and the like that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.
[0063] In the drawings and specification, illustrative embodiments are disclosed. However, many variations and modifications of these embodiments are possible. Accordingly, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. The scope of the embodiments is defined in the following claims.
Claims
1. 1. An assembly for use with a battery pack including a plurality of battery cells, the assembly being adapted to enable communication between an electronic device and a wireless transceiver located remotely from the electronic device, the assembly comprising: a modular antenna operably connected to the electronic device, the modular antenna including a first coil and a second coil, the first coil and the second coil being electrically conductive; a bus antenna configured to provide a communication channel with the wireless transceiver, the bus antenna including two transmission lines, each of the two transmission lines being disposed adjacent to a different one of the first coil and the second coil and spaced apart, the bus antenna being configured to enable short-range coupling between the module antenna and the bus antenna when a transmission signal is input to either the module antenna or the bus antenna; and The arrangement of the two transmission lines relative to the coils is such that the induced currents in each transmission line caused by coupling of each transmission line with its adjacent coil are substantially equal in magnitude. The arrangement of the two transmission lines relative to each of the coils is configured such that the currents induced in each transmission line by coupling of each transmission line with its adjacent coil are substantially equal in magnitude.
2. 10. The assembly of claim 1, wherein, in operation, the module antenna and the bus antenna function as a balun, such that when the transmission signal comprises an unbalanced electrical signal input to the module antenna, it is output as a balanced electrical signal at the bus antenna, or when the transmission signal comprises a balanced electrical signal input to the bus antenna, it is output as an unbalanced electrical signal at the module antenna.
3. 3. The assembly of claim 1, wherein for each of the transmission lines of each bus antenna, a longitudinal axis of the transmission line is oriented perpendicular to a longitudinal axis of an adjacent coil corresponding to the respective transmission line.
4. 10. An assembly according to any preceding claim, wherein the first coil and the second coil are configured to share the same longitudinal axis.
5. 10. An assembly according to any preceding claim, wherein the first coil and the second coil comprise at least one of the following characteristics: equivalent cross-sectional area, equivalent number of turns of the conductor, equivalent electrical resistance, equivalent core material.
6. 10. An assembly according to any preceding claim, wherein each transmission line of the bus antenna comprises at least one of the following characteristics: equivalent cross-sectional area, equivalent electrical resistance, equivalent magnetic permeability.
7. Assembly according to any of the preceding claims, wherein each transmission line of the bus antenna is positioned equidistant to different coils of the module antenna.
8. Assembly according to any of the preceding claims, wherein the first coil and the second coil are wound along the same direction of rotation.
9. 8. The assembly of claim 1, wherein the first coil and the second coil are wound along opposite rotational directions.
10. 10. The assembly according to claim 8 or 9, wherein the first coil and the second coil are connected in series or by a singular node.
11. 10. An assembly according to any preceding claim, wherein the two transmission lines of the bus antenna are configured as a balanced circuit such that an electrical signal propagating on a first of the two transmission lines is π radians out of phase with an electrical signal propagating on a second of the two transmission lines.
12. Assembly according to any preceding claim, wherein each transmission line of the bus antenna is connected at one end to a termination resistor.
13. 10. An assembly according to any preceding claim, wherein the separation distance between each transmission line of the bus antenna and its adjacent coil is selected to provide a coupling strength of at least -50 dB and not more than -10 dB.
14. 14. The assembly of claim 13, wherein a separation distance between each transmission line of the bus antenna and its adjacent coil is selected to provide a coupling strength of at least −40 dB and at most −20 dB.
15. Assembly according to claim 13 or 14, wherein the separation distance is selected to provide a coupling strength of not less than -35 dB and not more than -25 dB.
16. Assembly according to any one of claims 13 to 15, wherein the separation distance is selected to obtain a coupling strength of -30 dB.
17. 10. An assembly according to any preceding claim, wherein each transmission line of the bus antenna and its adjacent coil are insulated by a dielectric insulating material.
18. 20. The assembly of claim 17, wherein the dielectric insulating material comprises any one of the following: air, a plastic material, a glass-filled plastic material, an epoxy composite material.
19. 20. The assembly of claim 17, wherein said dielectric insulating material comprises any one of the following: polyethylene terephthalate "PET", acrylonitrile butadiene styrene "ABS", polytetrafluoroethylene "PTFE", polyvinyl chloride "PVC", polybutylene terephthalate "PBT", polyethylene "PE", polyamide "PA".
20. 18. The assembly of claim 17, wherein said dielectric insulating material comprises any one of the following: FR4, ceramic filled polytetrafluoroethylene "PTFE", ceramic laminate, Mylar.
21. Assembly according to any preceding claim, wherein the first coil and the second coil are air core coils.
22. 10. An assembly according to any preceding claim, wherein the first coil and the second coil are wrapped around a material.
23. 23. The assembly of claim 22, wherein the material comprises at least one of the following: a plastic insulating material, a ferrite, or a ceramic.
24. 10. An assembly according to any preceding claim, comprising a printed circuit board "PCB" containing the electronic device, the PCB containing the modular antenna.
25. 25. The assembly of claim 24, wherein the first coil and the second coil are integrated within the PCB substrate.
26. 26. The assembly of claim 25, wherein the first coil and the second coil are formed by a plurality of tracks and vias.
27. Assembly according to any of the preceding claims, wherein the first coil and the second coil are connected to a capacitor.
28. A battery cell comprising an assembly according to any preceding claim.
29. 28. A battery pack having a plurality of battery cells and including the assembly of any one of claims 1 to 27, wherein each battery cell is associated with an electronic device, and the assembly enables communication between each electronic device and a wireless transceiver located remotely from the battery pack via the bus antenna and the module antenna.