Parallel Electrical Connection Research Articles

Matching the Photocurrent of 2‐Terminal Mechanically‐Stacked Perovskite/Organic Tandem Solar Modules by Varying the Cell Width

Photocurrent matching in conventional monolithic tandem solar cells is achieved by choosing semiconductors with complementary absorption spectra and by carefully adjusting the optical properties of the complete top and bottom stacks. However, for thin film photovoltaic technologies at the module level, another design variable significantly alleviates the task of photocurrent matching, namely the cell width, whose modification can be readily realized by the adjustment of the module layout. Herein, this concept is demonstrated at the experimental level for the first time for a 2T‐mechanically stacked perovskite (FAPbBr3)/organic (PM6:Y6:PCBM) tandem mini‐module, an unprecedented approach for these emergent photovoltaic technologies fabricated in an independent manner. An excellent I sc matching is achieved by tuning the cell widths of the perovskite and organic modules to 7.22 mm (PCE PVKT‐mod = 6.69%) and 3.19 mm (PCE OPV‐mod = 12.46%), respectively, leading to a champion efficiency of 14.94% for the tandem module interconnected in series with an aperture area of 20.25 cm2. Rather than demonstrating high efficiencies at the level of small lab cells, this successful experimental proof‐of‐concept at the module level proves to be particularly useful to couple devices with non‐complementary semiconductors, either in series or in parallel electrical connection, hence overcoming the limitations imposed by the monolithic structure.

Integration of a lithium-ion battery in a micro-photovoltaic system: Passive versus active coupling architectures

A balcony photovoltaic (PV) system, also known as a micro-PV system, is a small PV system consisting of one or two solar modules with an output of 100–600 Wp and a corresponding inverter that uses standard plugs to feed the renewable energy into the house grid. In the present study we demonstrate the integration of a commercial lithium-ion battery into a commercial micro-PV system. We firstly show simulations over one year with one second time resolution which we use to assess the influence of battery and PV size on self-consumption, self-sufficiency and the annual cost savings. We then develop and operate experimental setups using two different architectures for integrating the battery into the micro-PV system. In the passive hybrid architecture, the battery is in parallel electrical connection to the PV module. In the active hybrid architecture, an additional DC-DC converter is used. Both architectures include measures to avoid maximum power point tracking of the battery by the module inverter. Resulting PV/battery/inverter systems with 300 Wp PV and 555 Wh battery were tested in continuous operation over three days under real solar irradiance conditions. Both architectures were able to maintain stable operation and demonstrate the shift of PV energy from the day into the night. System efficiencies were observed comparable to a reference system without battery. This study therefore demonstrates the feasibility of both active and passive coupling architectures.

Control of a thermoelectric cooling unit complex mixed electrical connection in an uneven temperature field

A possibility of optimal thermal management of a number of temperature-dependent and heat-laden elements of radio electronicequipment with different power dissipation in an uneven temperature field using a set of thermoelectric cooling devices with mixed electrical connection and fixed geometry of thermocouple branches has been considered.Ratios for determining the relative operating current corresponding to the minimum supply voltage at a given thermal load for different temperature gradients and thermocouple branch geometries are derived. The possibility of selecting a supply voltage for a group of thermoelectric coolers with parallel electric connection using both analytical and graphical methods of solving a system of algebraic equations of first and second orders is shown. The basic parameters, reliability indices and dynamic characteristics of a thermoelectric cooler complex with mixed electrical connection when a group of thermoelectric coolers with series electrical connection operates at maximum cooling capacity and supply voltage variation of a group of coolers with parallel electrical connection are evaluated. Analysis of the research results showed the possibility of selecting the optimum supply voltage for a group of thermoelectric coolers with parallel electric connection in the interrelation of energy, mass-dimensional and dynamic characteristics, taking into account the reliability indicators of the complex as a whole. It is shown that by reducing the supply voltage of a group of thermoelectric coolers with parallelelectric connection included in the complex, the energy, mass-size and dynamic characteristics are improved, and the reliability of the complex with mixed electric connection in an uneven temperature field is increased.

A Novel Forked-Finger Electrode-Structured Thermoelectric Module with High Output Power

Thermoelectric harvesting technology is a clean and friendly energy-conversion technology. In the π-type traditional thermoelectric module (TEM), n- and p-type thermoelectric legs are electrically connected in a series to generate large temperature differences in the heat flow direction and to achieve a better module performance. However, damages to one thermoelectric leg could lead to the failure of the thermoelectric system. This work proposes a novel forked-finger electrode-structured thermoelectric module (FFTEM), which enables a simultaneous parallel electrical connection and thermal transfer in a homogeneous material’s thermoelectric leg set. The four thermoelectric legs share a common pair of electrodes, and this parallel structure makes the FFTEM benefit from low internal resistance, a high operating current, and high output power. The internal resistance and output power of the TEM are 4.25 mΩ and 1.766 mW, respectively, at a temperature difference of 40 °C. The internal resistance of the FFTEM is reduced to 0.81 mΩ, and the output power is increased to 13.81 mW. The FFTEM’s maximum output power achieved under temperature-dependent conditions is nine times that of the TEM’s output power. This FFTEM design provides a configuration to obtain a much higher output power, which could benefit future applications of thermoelectric devices.

Performance assessment of stacked air-cathode microbial fuel cells under series and parallel electrical connections

Microbial fuel cells (MFCs) are playing an important role in the context of sustainable energy development. They represent a sustainable approach to harvest electricity from biodegradable materials. However, harvesting energy from MFCs represents a critical issue because of the low output voltage and power produced. Realizing stacked configurations may involve an increase in MFCs performances in terms of output voltage, current and electric power. In this paper, two stacked configurations under different electrical connection modes have been designed, developed, modeled and tested. The stacked MFCs consist of 4 reactors (28 mL x4) that are connected in series, and parallel-series modes. Three different tests have been carried out, which involves: 1) performing the polarization and power curves by applying decreasing resistances; 2) assessment of the electric behavior of each reactor over time at a fixed resistance, 3) performing the polarization and power curves by applying increasing resistances. Moreover, a numerical model for predicting the transient behavior of the electrical quantities for one reactor, has been developed and validated by using the experimental data. As expected, the results highlighted that the parallel-series configuration assures the highest volumetric power density compared to the series configuration, reaching the maximum value of 1248.5 mW/m3 (139.8 µW) at 0.291 mA. Eventually, by comparing the numerical and the experimental data, it has been demonstrated that the developed model is able to predict the reactor’s electrical trend with a good accuracy.

Piezomagnetic cantilever stator energy harvester using Savonius wind rotor

This paper proposes the piezomagnetic cantilever beam energy harvester connected to the Savonius vertical axis wind turbine for micro-power generation. The system consists of a rotor plate that is driven by the vertical shaft of the turbine and a stator with a vertically installed piezoelectric cantilever beam. Several magnets are mounted on the rotor and one magnet is attached at the free end of the cantilever as a tip mass. The alternating magnetic interaction force between magnets on the stator and the rotor induces deflection and strain on the piezoelectric layer that generates power. The arrangement of the magnets, wind speed, and resistive loads are some parameters that play important roles in the output power that are relatively investigated by experiments with the same conditions. Based on experimental results, by increasing resistive load, output power increases and then decreases. The same trend was observed for the gap distance between magnets mounted on the rotor and the stator. The 11 mm gap, 60 mm distance from the center, and 33 kΩ were obtained for the arrangement of the magnets on the rotor and also resistive load which leads to the highest power density of 0.85 μWcm-2 at 9.5 m/s wind speed using the standard circuit. Adding a second piezoelectric cantilever causes 37% (1.17 μWcm-2) and 80% (1.54 μWcm-2) improvement in the output power compared to single piezoelectric for series and parallel electrical connection respectively.

Characterisation of thermal runaway behaviour of cylindrical lithium-ion battery using Accelerating Rate Calorimeter and oven heating

In this work, thermal runaway of lithium-ion battery was characterised under adiabatic and non-adiabatic conditions using Accelerating Rate Calorimeter (ARC) and oven respectively. Battery with higher electrical capacity demonstrated a higher tendency to experience thermal runaway with shorter induction time and resulted with a more energetic response, as indicated by higher maximum temperature rise. Oven tests at 190 °C were able to capture thermal runaway characteristics in batteries with 100% state-of-charge (SOC) only and resulted in a maximum temperature of 738–783 °C. Two batteries were more inclined to suffer thermal runaway as the induction time was reduced by 8.6% to 115.98 min, compared to 126.92 min for single cell. A further inclined by 15% to 107.72 min was recorded for two batteries with parallel electrical connection. Meanwhile, ARC was able to induce thermal runaway in 50% SOC battery and instigated exothermic thermal decomposition in 0% SOC battery due to the longer heating process. The maximum temperatures recorded from ARC tests were between 404 and 522 °C, lower than oven tests since some of the battery energy content was released slowly during the long self-heating period, leaving the battery with less energy for rapid release during thermal runaway.

How to balance the voltage in serially stacked bioelectrochemical systems

Stack configuration of multiple bioelectrochemical system (BES) modules is considered nowadays as the best option for a successful scale-up of this technology, either in case of electricity-producing microbial fuel cells (MFC) or in case of electricity-consuming microbial electrolysis or electrosynthesis cells (MEC or MES, respectively). While the parallel electrical connection allows to independently operate each BES in a stack without major issues, serially stacked BES are more appealing from the point of view of energy conversion, as they suffer lower energy losses and it is possible to operate them at higher voltages. However, in the case of MEC/MES cells connected in series, high performing bioanodes can push the less-performing ones in the stack outside their “working zone”, resulting in unfavorable potentials, uncontrolled voltage drops, and the temporal or permanent damage of the electroactive biofilm. A few cell balance systems (CBS) were proposed in the past but requiring expertise in power electronics. In this study an easy, passive and low-cost CBS based on commercial diodes is proposed. Three double-chamber MECs were adopted. A first set of experiments were performed to characterize the cells and understand reasons for voltage unbalance in a series-connected stack. Then, the CBS was adopted and validated.

Comparative study of different hydro-dynamic flow in microbial fuel cell stacks

• Different hydrodynamic configuration were investigated in MFC stacks. • Modified earthen membrane was utilized in the MFCs. • Parallel independent hydrodynamic connection showed the best power generation. This work has investigated the scale-up potential of microbial fuel cells (MFCs) under stacking mode. Stacking was done in batch mode and continuous mode. Batch feeding mode stacks were operated in electrical series (S) and parallel (P) mode. Continuous feeding mode stacks were kept in electrically parallel mode with different hydro-dynamic patterns. The two continuous stacks were connected hydro-dynamically in series ( i . e . Parallel Dependent; PD) and parallel ( i . e . Parallel Independent; PID) configurations. The performance of the continuous stacks was evaluated on the basis of COD consumption rate, power generation and coulombic efficiency. PID obtained highest power (0.47 mW) which was approximately 3.6 times that of PD configuration (0.13 mW). The rate of COD consumption was also highest in PID stack (3091.75 mg·L −1 ·d −1 ). Coulombic efficiency of the PID stack was 14.26% which was approximately 292.8% of the PD stack. The results confirmed that the parallel electrical connection hybridized with the independent hydro-dynamic flow gives the best possible results when working with stacking of MFCs.

Phase-Locking of Spin-Torque Nano-Oscillator Pairs by Magnetic Dipolar Coupling in Electrical Serial Connection

Synchronization of spin-torque nano-oscillators (STNOs) by magnetic dipolar interactions in a parallel electrical connection (PC) introduces the technological possibility for an enhancement of output signal. In this study, we consider two identical or nonidentical STNOs in serial electrical connection (SC). By using a pendulum-like approximation model, we analytically predict the dipolar coupling strength, critical current and frequency of phase-locking precession. The numerical calculations of those analytical expressions are confirmed by macrospin simulations, revealing that the dipolar coupling strength responsible for the phase-locking in SC case is three times larger than that in the PC case for the two STNOs with the same separation, which results in the enlarged and symmetric phase-locking window of frequency versus current. These results suggest that the SC of multiple STNOs could be more promising for the enhancement of output power.

Investigation of magnetoelectric multilayer laminate composites with series and parallel electrical connections

AbstractThis paper investigates the performance of magnetoelectric composites composed of multilayer magnetostrictive and piezoelectric laminates in which the series and parallel electrical connections are applied. The multiphysics simulations have been performed according to the different longitudinal and transversal magnetization and polarization modes using a numerical model based on the finite element method and an analytical formulation based on the equivalent circuit model. The obtained results highlight the limitation of the analytical formulation to model the multilayer composites when an alternative opposing polarization between each neighboring piezoelectric layer is applied.

Multi-objective optimization of a triple layer piezoelectric bender with a flexible extension using genetic algorithm

ABSTRACTThis article presents an electromechanical analysis for a piezoelectric bimorph actuator with a flexible extension, which is used to increase the tip deflection. The performance measuring attributes of such an actuator are derived, and a genetic algorithm is used for multi-objective optimization. The analysis reveals that for a thick flexible extension, the length of the extension provides Pareto optimal solutions for multi-objective optimization. The analysis also shows that as the thickness of the flexible extension decreases, the Pareto optimal solutions converge to a single solution for multi-objective optimization. We have considered nonlinear deflection behavior of piezoelectric materials at high electric fields, and series and parallel electrical connections in the analysis.

Active filter driver for piezo-actuators for flapping-wing micro air vehicles

Piezoelectrically actuated flapping-wing micro air vehicle (MAV) is an emerging technology. This paper discusses limitations of presently used voltage drivers for the piezoelectric actuators used in such applications and suggests an active filter-based unipolar high-voltage driver. A Chebyshev polynomial has been used to extract a unipolar sinusoidal high voltage signal from a unipolar square wave signal for driving the piezoelectric actuators at low frequency in flapping-wing MAV applications. The filter is based on Sallen–Key topology and is suitable for connecting a piezo-bimorph in series or parallel electrical connection. We have considered an application-specific piezoelectric bimorph actuator of 40 Hz flapping frequency and 32 nF capacitance in each piezoelectric layer to design a driver. The driver circuit in verified by simulation results of OrCAD® software. The driver circuit can control the frequency of the sinusoidal driving voltage, which causes wing-flapping, by radio control communication.

Lightweight High Voltage Electronic Circuits for Piezoelectric Composite Actuators

The purpose here is to enable peak-to-peak actuation of piezocomposite devices to perform shape control of structures, specifically bimorph variable-camber control surfaces on small aircraft. One of the major drawbacks in implementing control with piezocomposite actuation is its asymmetry in the positive and negative voltage directions. To remedy this situation, a novel, solid-state electrical circuit employing diodes and resistors is proposed. The circuit allows a single bipolar amplifier to control a bimorph composed of two piezoceramic composite actuators known as Macro-Fiber Composite (MFC). The MFCs have an asymmetric actuation range of -500 to 1500 V; hence an MFC bimorph with conventional serial or parallel electrical connection limits the actuation to the -500 to 500 V range. The proposed circuit allows the division of the input voltage so that: (1) The MFC that is in extension receives 1500 V, and (2) The MFC that is in compression receives -500 V. The circuit also allows the actuation in the opposite direction without any physical changes (i.e., not using any electromechanical switches) The input-output relationship of the circuit is characterized experimentally. An MFC bimorph is used to further demonstrate the capability of the circuit.

Modular speaker cabinet

A speaker cabinet design for providing adjustability of the number of speaker cabinets contained in a speaker array comprises female connectors ( 50 ) along the front and back edges on the top and right sides. A user of the cabinet can attach a mating second cabinet to any side of the first cabinet by inserting male connector ( 40 ) in the pass through assembly and securing to the female connector at all locations on that side. A user can connect a second speaker cabinet in a series or parallel electrical connection. This allows the user to build up to the desired number of speakers without purchasing a full speaker array. Furthermore, once the desired array is complete the user can remove only the number needed for transport. A variety of different speakers can be preloaded in the cabinet at the factory, thus giving the user flexibility in sound without having to remove and install different speakers.

Development of a fabrication process for parallel multijunction thin film silicon solar cells on wafer substrates

The parallel multijunction (PMJ) cell design theoretically enables high efficiency thin film polysilicon solar cells at lower cost. Since its initial proposal in 1994 the PMJ cell has been the subject of a number of theoretical studies, however, no detailed experimental investigation has yet been reported. Any systematic study of the PMJ solar cell will require suitably designed and fabricated devices to serve as experimental test-beds. This paper reports the successful development of a fabrication sequence for PMJ cells in CVD-epilayers on inert single-crystal silicon substrates, producing cells with efficiencies up to 13%. The processing sequence is based on photolithography, anisotropic wet etching, high temperature furnace steps and evaporated metallisation. Full details of the processing sequence are provided, with explanations of particular process choices, including the method of parallel electrical connection of like-polarity layers, the use of a thick photoresist (Shipley SJR5740), avoiding pitfalls, and procedures to minimise cell shunt behaviour. The establishment of this baseline fabrication sequence for PMJ cells opens up a wealth of opportunities for systematic studies of cell performance limiting mechanisms, such as junction recombination, and the implications of various cell design and processing options, particularly those likely to be of more commercial relevance, such as laser scribing, laser doping, rapid thermal processing and electroless metal plating. Copyright © 2000 John Wiley & Sons, Ltd.

Vibration detector incorporating two or more seismic elements

ABSTRACT OF THE DISCLOSURE The present invention provides a vibration responsive detector comprising at least one pair of parallel, electrically conductive rods, at least two seismic elements, having electrically conductive outer surfaces, mounted on the rods of said one pair so as to provide parallel electrical connections between these two rods, characterised in that positioning means are provided for urging each seismic element into contact with an adjacent seismic element so as to ensure electrical connection between adjacent elements irrespective of relative movement of adjacent elements transversely of the rods.