RESUMEN
Power line communication within a lithium-ion battery allows for high fidelity sensor data to be transferred between sensor nodes of each instrumented cell within the battery pack to an external battery management system. In this paper, the changing characteristics of the lithium-ion cell at various states of charge are measured, analysed, and compared to understand their effectiveness on the communication channel of a power line communication system for carrier frequencies of 10 MHz to 6 GHz. Moreover, the use of quadrature amplitude modulation (QAM) is investigated to determine its effectiveness as a state-of-the-art modulation method for the same carrier frequency range. The overall results indicate that certain carrier frequencies and QAM orders may not be suitable for the in situ battery pack power line communication due to changes in battery impedance with certain lithium-ion cell states of charge, which cause an increase in error vector magnitude, bit error ratio, and symbol error ratio. Recommendations and trends on the impact of these changing characteristics based upon empirical results are also presented in this paper.
RESUMEN
In anticipation of the hybrid utilisation of the radio frequency (RF) wireless transceiver technology embedded in future smart Li-ion battery cells to deliver hybrid links based on power line communication (PLC) and wireless connections, herein we present an empirical high-frequency investigation of the direct current (DC) bus. The focus is to determine, via statistical tools including correlation coefficient (CC), root mean squared error (RMSE) and feature selective validation (FSV) method, the impedance and signal change impact on a possible communication link when fully charged cells are present or completely missing from the bus. Moreover, to establish if technological differences may be accounted for during the empirical experiments, Li-ion cells from two different manufacturers were selected and connected via three subsequent capacitive couplings of 1 µF, 1 nF and 1 pF. According to a methodical comparison by employing CC, RMSE, and FSV over the measured impedance and signal attenuation, this study has shown that the physical DC network is the dominant impedance at high frequencies and that the signal attenuation on the DC line supports communication in the investigated spectrum. The reported findings are critical for in situ hybrid PLC and wireless communication implementation of BMS for Li-ion systems supported through only one RF transceiver.
RESUMEN
As the RF communication on 18650 Li-ion cell level has not been reported due to its challenges and constrains, in this work, a valid wireless data link is demonstrated in an enclosed empty metal shell at 868 MHz and 2.4 GHz based on the IEEE 802.15.4 standard. The experimental tests are carried out using two generic unturned radiative structures, a wire loop fitted inside a cell shell, and an open terminal sub miniature version A (SMA), subsequently oriented vertically and horizontally relative to the ground plane. Based on signal strength indicator, bit error rate, and packet error rate, the test characterized a payload of 120 bytes at the highest speed of 150 kbps and 250 kbps supported by the IEEE 802.15.4 for the two communication frequencies. A MATLAB simulation is used in parallel to determine the three-dimensional radiative pattern of the two structures, whereas a three-ray model for multipath range propagation is implemented to complete the empirical experiments. It was demonstrated through testing communication of up to 10 m for both operating frequencies, proving the concept of wireless cell communication within short ranges, an essential feature for monitoring the health of each cell inside future electric vehicles (EVs).
RESUMEN
Efficient management through monitoring of Li-ion batteries is critical to the progress of electro-mobility and energy storage globally, since the technology can be hazardous if pushed beyond its safety boundaries. Battery management systems (BMSs) are being actively improved to reduce size, weight, and cost while increasing their capabilities. Using power line communication, wireless monitoring, or hybrid data links are one of the most advanced research directions today. In this work, we propose the use of radio frequency (RF) transceivers as a communication unit that can deliver both wired and wireless services, through their superior analog and digital signal processing capability compared to PLC technology. To validate our approach computational simulation and empirical evaluation was conducted to examine the possibility of using RF transceivers on a direct current (DC) bus for wired BMS. A key advantage of this study is that it proposes a flexible and tested system for communication across a variety of network scenarios, where wireless data links over disrupted connections may be enabled by using this technology in short-range wired modes. This investigation demonstrates that the IEEE 802.15.4-compliant transceivers with operating frequencies of 868 MHz and 2.4 GHz can establish stable data links on a DC bus via capacitive coupling at high data rates.
RESUMEN
Thermoresponsive surfaces featured with nanostructures have found wide potential applications in biological and chemical fields. Herein, we report nanostructured thermoresponsive surfaces engineered via stable immobilization of thermoresponsive nanogels with the assistance of polydopamine. The results show that the thin layer of polydopamine on the poly( N-isopropylacrylamide) (PNIPAM) nanogels nearly does not affect the thermoresponsive property of the nanogels. The stability of the thermoresponsive nanogels on the substrate surfaces immobilized under different pH conditions of dopamine solutions are quatitively studied by fluid shearing experiments inside capillaries, and the characterization results show that the strong interaction forces between the polydopamine layer on the substrate surfaces and the thermoresponsive nanogels are heavily dependent on the oxidation state of the dopamine molecules. With the proposed strategy, thermoresponsive nanostructured surfaces immobilized with PNIPAM nanogels on two-dimensional and three-dimensional substrate surfaces are generated to achieve smart cell culture plates and smart gating membranes, respectively, which demonstrate versatile applications of the nanostructured thermoresponsive surfaces.