Non-uniform Current Distribution Research Articles

Eddy Current Transducer with Rotating Permanent Magnets to Test Planar Conducting Plates.

In this paper, we present an eddy current transducer with rotating permanent magnets for the inspection of planar conducting plates. The transducer consists of a rotating head with permanent magnets, which is used to generate variable magnetic fields and thus induce eddy currents in the tested material. Two Hall sensors connected in a differential manner are used to detect a nonuniform distribution of eddy currents induced in a specimen containing a defect. To prove the usability of the transducer, a number of experiments were conducted on thick aluminum samples containing notches at different depths. Selected results of the achieved measurements are presented.

Investigation on Current Distribution and Joint Resistance-Overlap Length Relationship for Non-Superconducting Joints

Low-resistance joint technology is crucial for high-temperature superconducting (HTS) closed-loop coils that work in persistent current mode. The non-uniform current distribution (NUCD) phenomenon in HTS joint has a significant influence on joint resistance, which may lead to a nonlinear relationship between joint resistance Rj and overlap length l (Rj-l curve) instead of following the laws of resistance. In this paper, an arched structure joint made by YBCO tapes has been designed to provide a direct evidence for the NUCD phenomenon inside solder joint. It is found that the current transports mainly at the end of the overlap area and is much different from the regular conductors. The V/I-I method is proposed to measure Rj of solder joints (less than 2 nΩ) with various overlap lengths in order to obtain more precise data. A complete Rj-l curve (l = 5-100 cm) has been successfully illustrated and a nonlinear saturation relationship between Rj and l is presented. The joint resistance tends to approach to a lower limit value about 1.5-1.6 nΩ when the overlap length exceeds 20 cm.

Current Density Distribution in Electrochemical Cells with Small Cell Heights and Coplanar Thin Electrodes as Used in ec-S/TEM Cell Geometries

The electrochemical engineering aspects of high aspect ratio cells, such as those used in in situ electrochemical scanning transmission microscopy (ec-S/TEM) were examined, focusing on aspects that could cause non-uniform current distribution. Having a uniform current distribution across the working electrode is important for any spectroelectrochemical technique in order to provide accurate electrochemical information as well as structural electrolyte-electrode interface information. An analytical model was developed to determine current density distribution and a Wagner number was derived for a small cell height with coplanar electrodes. The main assumptions of this analysis are: 1) mass transport effects are negligible, 2) a uniform potential distribution in the direction of the cell height due to their small size, and 3) the working electrode potential is constant across its length. With our analysis, the assumptions were found to be reasonable. In addition, the effect of the conductivity and thickness of the thin film electrode and its potential effect on current density distribution have been analyzed. Now, with this work, high aspect ratio cells with a small cell heights and coplanar thin electrodes can be analyzed to determine their current density distribution.

The effects of anode distance and corrosion activity on current distribution for ICCP systems

One of the most effective techniques to mitigate corrosion of steel reinforcement in concrete is impressed current cathodic protection (ICCP). This technique has been widely used for several decades; however, there is limited research systematically studying the various factors affecting the distribution of cathodic current over the area of steel reinforcement. Understanding how current is distributed in an ICCP system is crucial for its design to ensure that all areas of steel are sufficiently protected, and overprotection of certain areas is avoided. In this study, the effect of distance of the anode from the steel and level of corrosion on current distribution is investigated by applying a potential sweep and measuring the steel potential and current for specimens with three layers of steel at different depths. The findings from this study revealed an inverse relationship between cathodic polarisation with steel distance from the anode and that higher levels of corrosion can cause a more non-uniform current distribution favouring the closest bar to the anode.

Analysis of transient current distribution characteristics of Press Pack IGBT

In the switching process of Press Pack IGBT (PPI) module, the phenomenon of nonuniform current distribution invariably happens which reduce the reliability and life time of chips and the module. The uneven current distribution would be caused by some physical reasons such as the clamp force, the temperature; and the electrical reasons including the parasitic inductance of the emitter pillars, the parasitic resistance of the gate connector and the difference of the paralleled chips characteristic, etc. Based on the modeling of two disparate module structures, the parasitic parameter of the emitter pillars and gate connector is extracted in this paper. Then the different equivalent circuits of PPI module are built due to the researches in different factors with the Synopsys Saber software. At last, by comparing the influence of two modules indifferent factors, the simulation results prove the relationship between the pillars distribution and the chip switching losses.

Design and analysis of a high quality factor multipath spiral inductor

Recently high quality factor and small-occupying-area inductors are prerequisite for wireless communication products such as mobile phones and wireless network, low cost and high performance on chip radio-frequency devices and microwave integrated circuit applications. In high frequencies, non-uniform current density distribution in the edge of the coil due to skin effect and proximity effect increases effective resistance of inductor and reduces the quality factor. This paper presented a multipath circular spiral inductor. The multipath technique reduces the skin and proximity effects, therefore increases the quality factor of the inductors. Simulation has been taken using COMSOL Multiphysics software. The results show maximum quality factor of proposed inductor have been achieved about 79 at 230 MHz that have been improved around 73% compared with conventional one. The dimension of the inductor is 2300 µm × 2300 µm. The small size proposed structure with high Q-factor is sufficient for the wireless applications.

Modeling of current distribution in zinc oxide varistors using Voronoi network and finite element method

Nonuniform current distribution inside varistor ceramics is a key factor influencing its performance and failures. Therefore understanding, modeling and predicting of current distribution in varistor ceramics is of crucial significance. This paper proposes a numerical model for simulation of nonuniform electric current distribution inside zinc oxide varistors. A numerical model is based on physical modeling of the varistor's grain-structured geometry presented by Voronoi network using finite element method (FEM) simulation. The presented method is solving complete electric field inside the modeled geometry and therefore provides a more physically accurate approach for better understanding and predicting nonuniform current distribution in the varistor. In order to properly establish a FEM model a novel approach in defining grain boundary characteristic is proposed. Thus, a macroscopic model of the varistor microstructure has been developed and the grain micro-junction boundary characteristic has been derived. The simulation results of nonuniform current distribution in a varistor agree well with measurement results for a typical ZnO varistor. The presented model enables investigation of influences of varistor geometry (shapes, sizes) and material properties on the current distribution. A new mathematical expression for varistor I–V characteristic based on Lambert function is proposed.

Characterizing Lithium-Ion Cell State with a Streamlined Electrochemical/Thermal Model Parameterized By Lock-in Thermography

Large-format prismatic lithium-ion cells have high surface-to-volume ratios, and the positioning of the tabs can make the temperature distribution highly non-uniform across the cell surface [1]. When cells are interconnected, the wiring configuration can induce non-uniform pack-level current distributions, leading to varied cell usage [2]. Non-uniformity of either type is a problem because local thermal runaway can occur at ‘hot spots’ and spread to other regions of a cell, or to other cells in a pack [3]. Even in cases of non-catastrophic failure, non-uniformity leads both to ineffective usage of active materials at the cell level and to an unknown distribution of health across cells salvaged from retired packs. These inefficiencies can be leveraged in a positive way, however, because they allow the correlation of external measurements such as temperature distribution and voltage with internal material properties. A 3-D physics-based model based on the Newman-Tobias porous-electrode theory [4] was developed, augmented with a local energy balance, and implemented in COMSOL Multiphysics® to predict electrical and thermal behaviour. Various material properties corresponding to relevant observable lock-in thermography signatures can be extracted by fitting the model to experimental data. Square-wave current signals with amplitudes ranging from 1 C to 4 C and periods ranging from 20 s to 100 s were applied to A123 20 Ah LiFePO4 cells. These signals keep the average state of charge (SOC) relatively constant, eliminating concerns about how material properties change with SOC [5]. Temperature-distribution and voltage data are gathered together as the battery response reaches a periodic steady state. Parameter sets are extracted by fitting model output to the lock-in thermography data from the most strenuous test (i.e. highest C-rate and longest period). The model has been validated by using parameters extracted from the most strenuous test to simulate tests with different amplitude and period. Characterization of parameter vectors by the above technique across a cell’s available charge states produces a database that can be compared to data from other batteries to diagnose their states. Figures 1A and 1B show lock-in thermography data and model best-fits at the most strenuous testing condition (4 C amplitude and 100 s period about a mean SOC of 50%). Figures 1C and 1D show similar information from the same cell around a different mean SOC of 30%. Table 1 shows the two parameter sets used to simulate these results, giving us insight into SOC-dependent electrical and thermal parameter values. State-of-health analysis of a cell can be performed by gathering a broader property database from lock-in-thermography, encompassing parameter vectors from various points in a battery’s cycling history. This ‘health fingerprint’ could be used to quickly diagnose cells salvaged from larger packs with unknown cycling history. Robinson, J.B., et al., Detection of Internal Defects in Lithium-Ion Batteries Using Lock-in Thermography. ECS Electrochemistry Letters, 2015. 4(9): p. A106-109.Offer, G., et al., Module design and fault diagnosis in electric vehicle batteries. Journal of Power Sources, 2012. 206: p. 383-392.Bandhauer, T.M., S. Garimella, and T.F. Fuller, A Critical Review of Thermal Issues in Lithium-Ion Batteries. Journal of The Electrochemical Society, 2011. 158(3): p. R1-R25.Newman, J.S. and C.W. Tobias, Theoretical Analysis of Current Distribution in Porous Electrodes. Journal of the Electrochemical Society, 1962. 109(12): p. 1183-1191.Maleki, H., et al., Thermal Stability Studies of Li-Ion Cells and Components. Journal of The Electrochemical Society, 1999. 146(9): p. 3223-3229. Figure 1

Influence of Impulse Current Waveform on Current Distribution of Parallel-connected Multi-column Arresters

In order to improve the energy absorption ability of the surge arrester, the high-voltage DC transmission system which has long duration and high energy overvoltage usually adopts paral-lel-connected multi-column arresters. The uniformity of the current distribution between columns determines the total energy absorption capacity of the arrester. In this paper, the effect of impulse current waveform on the non-uniformity of current distribution between four-column parallel valves is studied by testing the arrester of two manufacturers, and the results show that the waveform of the impulse current has a certain effect on the current non-uniformity, but the effect will not exceed the standard value.

Equation-Based Optimization for Inductive Power Transfer to a Miniature CMOS Rectenna

This work presents an analytical approach for optimizing the single-ended (SE) and differential (DF) reader coils and miniature rectenna designs in near-field inductive power transfer (IPT) systems. In this design context, the appropriate operation frequency is in the gigahertz range, and the nonuniform current distribution on the reader coil and the radiation resistance must be considered and are included in this paper. Utilizing the rectenna miniaturization, the reader coil and the rectenna designs can be decoupled and their figure of merits (FOMs) are identified. The equation-based approach optimizes the IPT design rapidly, and the optimized reader-coil FOM and the optimized rectenna FOM, both plotted versus the IPT frequency, co-decide the optimal IPT frequency and the coil geometries for the highest RF-dc power transfer efficiency. The analytical method is verified by EM-simulation and measurement, and the DF reader coil topology is demonstrated to be more efficient than the commonly used SE coils. An optimized 2.2-mm IPT with a DF coil is realized at 4.8 GHz and significantly outperforms the previous works. Under a total RF power of 33.1 dBm, the CMOS rectenna, with a coil size of only 0.01 mm2, harvests the designed dc conditions of 1 V/0.1 mA.

Design and analysis of a novel MEMS spiral inductor with high quality factor

In this paper a novel spiral inductor with high quality (Q)-factor is presented. Non-uniform current density distribution, especially in inner turn, increases the effective metal resistance due to skin and proximity effect. In order to overcome this problem, an improved inductor layout with non-uniform metal width and non-uniform spacing is proposed to increase the quality factor. For this inductor layout, from outer coil to inner coil, the metal widths are reduced but spacing between strips are increased. Mainly due to the decrease of eddy current loss by weakening the current crowding effect in the center of the spiral inductor. By reducing the current crowding effect, the effective resistance is minimized, thereby increase the quality factor. Simulation has been taken using COMSOL Multiphysics software. The results indicate that maximum value of quality factor and self-inductance of the novel inductor have been obtained about 80.34 and 324 nH, respectively. Which Q-factor improves 27% more than conventional inductors with uniform width. The dimension of the inductor is 1700 × 1660 μm.

Electrode parameters and operating conditions influencing the performance of anion exchange membrane fuel cells

A deeper understanding of porous electrode preparation and performance losses is necessary to advance the anion exchange membrane fuel cell (AEMFC) technology. This study has investigated the performance losses at 50 °C for varied: Tokuyama AS-4 ionomer content in the catalyst layer, Pt/C loading and catalyst layer thickness at the anode and cathode, relative humidity, and anode catalyst. The prepared gas diffusion electrodes in the interval of ionomer-to-Pt/C weight ratio of 0.4–0.8 or 29–44 wt% ionomer content show the highest performance. Varying the loading and catalyst layer thickness simultaneously shows that both the cathode and the anode influence the cell performance. The effects of the two electrodes are shown to vary with current density and this is assumed to be due to non-uniform current distribution throughout the electrodes. Further, lowering the relative humidity at the anode and cathode separately shows small performance losses for both electrodes that could be related to lowered ionomer conductivity. Continued studies are needed to optimize, and understand limitations of, each of the two electrodes to obtain improved cell performance.

Integrated Joule switches for the control of current dynamics in parallel superconducting strips

Understanding and harnessing the physics of the dynamic current distribution in parallel superconducting strips holds the key to creating next generation sensors for single molecule and single photon detection. Non-uniformity in the current distribution in parallel superconducting strips leads to low detection efficiency and unstable operation, preventing the scale up to large area sensors. Recent studies indicate that non-uniform current distributions occurring in parallel strips can be understood and modeled in the framework of the generalized London model. Here we build on this important physical insight, investigating an innovative design with integrated superconducting-to-resistive Joule switches to break the superconducting loops between the strips and thus control the current dynamics. Employing precision low temperature nano-optical techniques, we map the uniformity of the current distribution before- and after the resistive strip switching event, confirming the effectiveness of our design. These results provide important insights for the development of next generation large area superconducting strip-based sensors.

Nonuniform current distribution within parallel-connected batteries

An imbalanced current distribution is often observed in cables of parallel batteries, which may limit the release of the energy and power in the battery pack. Hence, it is very important to analyze the homogeneous current distributions within parallel battery batteries and explore the effect on the state of charge and energy loss. Initially, it can be found that a battery near the load will experience a large local current under higher discharge rate. With the discharge, the current distribution will show a surge wave distribution, and the peak is gradually shifted backwards. As discharge continues, local current profile in segments will have different development trends, while current profile with lower initial current values increase, which leads to an entirely different form of current distribution with the initial stage of discharge. The current profile moves in a wavelike form transmission when the total discharge rate is low. The higher the current rate, the more divergent the current distribution. The state of charge distribution is also nonuniform, clearly indicating underutilization of active materials, which will further aggravate the nonuniformity of the local current distribution in the parallel battery pack.

Multifunctional Energy Storage Composites: Analysis and Optimization of Current Density Distribution

The introduction of electric vehicles (EVs) has posed many technical challenges to the automotive industry; in particular, the state-of-the-art lithium-ion (Li-ion) batteries add massive weight to vehicles both in the form of battery weight and supporting systems, immensely hindering vehicle performance and efficiency. A primary source of this challenge is that the battery packs serve only one purpose – energy storage, as current EV batteries do not carry loads or absorb collision impact energy. Recently introduced by the authors, a hybrid energy storage design, called the Multifunctional Energy Storage Composites (MESC), possesses the unique feature of simultaneously carrying tremendous structural loads and providing energy-storage capabilities (1-3). It has been demonstrated that the concept potentially leads to significant weight and volume savings in electric vehicle and system designs. In brief, the MESC involves a unique integration technique for embedding Li-ion battery materials in structural carbon-fiber-reinforced-polymers (CFRP). The crux of the multifunctional design is the incorporation of three-dimensionally interlocking “rivets” (1-3). The electrode layers, which make up the battery stack, contain a rectangular array of perforations (with diameter on the order of millimeters), instead of being solid, continuous, planar films. The perforations in each layer of the stack line up to fit the interlocking rivets, which three-dimensionally interlock the electrodes and rigidly anchor onto the stiff CFRP faceplates. The interlocking rivets exploit the intrinsic mechanical properties of the Li-ion battery electrodes, allowing them to carry mechanical loads. Despite the non-conventional cell construction, the MESC has demonstrated cycling and cycle-life performance tantamount to commercial pouch cells, with similar mechanical load carrying capabilities to automotive structural materials (2). Even though the rivets are indispensable in the MESC design and offer immense mechanical benefits, they present a slight electrochemical challenge. The presence of the perforations influences the current flow path, current density distribution, and depth of discharge (DoD) uniformity. Therefore, in this work, special attention is given to the numerical modelling and optimization of current density distribution in the electrodes, with the presence of a perforation array. Standard non-perforated graphite/NMC pouch cells are used to determine the DoD dependency of the intrinsic open-circuit voltage, electrochemical conductance, and resistance. The governing equations for charge conservation, polarization, and current density are solved numerically in COMSOL simulation (4-6). The perforations are included as boundary conditions on the electrode domains. The model is parameterized to capture various geometrically feasible perforation patterns, array densities, and diameters. Under different constant-current profiles, the non-uniformity of current density distribution and DoD is quantified. The increase in cell impedance, due to the local constriction and spreading of electrical current, is also evaluated. Complete functional relationships between perforation parameters (e.g. pattern, density, and hole diameter) and the electrochemical performance (current density distribution, DoD distribution, cell impedance, etc.) are established. Counter-intuitively, our results confirm minimal electrochemical impact in MESC cells with current path disruption sufficient for mechanical stabilization. Compared to unperforated cells of the same dimensions, less than a 10% increase in non-uniformity of current distribution and less than a 5% increase in cell impedance are observed. Beyond these indicative results, the model provides meaningful physical insights into the current flow path around the holes, as well as near the current collector tabs. Together, these allow the MSEC electrode design to be optimized in the electrochemical-mechanical tradeoff. Additionally, towards a broader context, it is believed this study will shed light upon electrode design and the optimization of conventional high-energy, high-power Li-ion batteries. To this end, a first step has already been taken to generalize the model and employ advanced optimization schemes e.g. genetic algorithms (GA). References P. Ladpli, R. Nardari and F.-K. Chang, Multifunctional Energy Storage Composites, WO patent application 2016127122, published 2016-08-11.P. Ladpli, R. Nardari, R. Rewari, H. Liu, M. Slater, K. Kepler, Y. Wang, F. Kopsaftopoulos and F.-K. Chang, Multifunctional Energy Storage Composites: Design, Fabrication, and Experimental Characterization, in ASME 2016 Energy Storage Forum, Charlotte, NC (2016).P. Ladpli, R. Nardari, Y. Wang, P. A. Hernandez-Gallegos, R. Rewari, H. T. Kuo, F. Kopsaftopoulos, K. D. Kepler, H. A. Lopez and F. Chang, Multifunctional Energy Storage Composites for SHM Distributed Sensor Networks, in International Workshop on Structural Health Monitoring 2015, Stanford, CA (2015).U. S. Kim, C. B. Shin and C.-S. Kim, Journal of Power Sources, 189, 841 (2009).K. H. Kwon, C. B. Shin, T. H. Kang and C.-S. Kim, Journal of Power Sources, 163, 151 (2006).J. Newman and W. Tiedemann, Journal of The Electrochemical Society, 140, 1961 (1993). Figure 1

Thermal-Mechanical-Electrochemical Coupling Simulation for Electric Vehicle Batteries

The major trend toward vehicle electrification intensifies the need for increased battery energy densities. During the development of new electric vehicle battery technologies, it has become clear that thermal, mechanical, and electrochemical coupling effects play an important role in battery performance, degradation, and response to abusive conditions. The macro-homogeneous Dualfoil model, which solves ion transport and charge transfer dynamics, predicts the electrical response of a single small battery cell. However, when considering large cells or assembled battery modules and packs, inhomogeneity of electric potential and temperature throughout the cell volume becomes severe enough to impact battery performance. Cell expansion and contraction during charge/discharge cycles further increase such inhomogeneity, and the resulting potential and temperature imbalances cause non-uniform current distribution in the cell. Heavily cycled cell regions generate additional heat and stress, causing severe degradation in the performance and life of the battery. Given the strong coupling between thermal, mechanical, and electrochemical phenomena, it is imperative to integrate multiple physical models in the simulation of complete battery packs. In this work, a modified Dualfoil electrochemical model is coupled to a thermo-mechanical finite element solver to represent such multiphysics coupling effects. Outputs from the 3D thermo-mechanical solver, such as temperature and stress, are supplied as inputs to the Dualfoil model, which in return computes the electrochemical response and provides the local heat generation rate and Li intercalation induced volume change to the thermo-mechanical solver. Using this coupled multiphysics simulation framework, the impact of external mechanical loading under different charge/discharge profiles was investigated. The transient, non-linear behavior of internal variables, such as SOC, overpotential, and current density, during and after cycles, was obtained in the entire 3D battery pack domain. This information provides good insights for design and optimization of battery packs with high performance and long life time.

Mechanical stress analysis during a quench in CLIQ protected 16 T dipole magnets designed for the future circular collider

Protecting the magnets in case of a quench is a challenge for the 16 T superconducting dipole magnets presently designed for the 100 TeV: Future Circular Collider (FCC). These magnets are driven to the foreseen technological limits in terms of critical current, mechanical strength and quench protection. The magnets are protected with CLIQ (Coupling-Loss Induced Quench) system, which is a recently developed quench protection method based on discharging a capacitor bank across part of the winding. The oscillation of the magnet currents and the dissipation of the high stored energy into the windings cause electrodynamic forces and thermal stresses, which may need to be considered in the magnet mechanical design. This paper focuses on mechanical stress analysis during a quench of the 16 T cos-θ and block type dipole magnets. A finite element model allowed studying the stress due to the non-uniform temperature and current distribution in the superconducting coils. Two different CLIQ configurations were considered for the cos-θ design and one for the block type magnet. The analyses of the mechanical behavior of two magnets during a quench without or with hot spot turn were separately carried out. The simulation results show that the stress related to a quench should be considered when designing a high field magnet.

Electrochemical characterization of high frequency stimulation electrodes: role of electrode material and stimulation parameters on electrode polarization

Objective. With recent interest in kilohertz frequency electrical stimulation for nerve conduction block, understanding the electrochemistry and role of electrode material is important for assessing the safety of these stimulus protocols. Here we describe an approach to determining electrode polarization in response to continuous kilohertz frequency sinusoidal current waveforms. We have also investigated platinum, iridium oxide, and titanium nitride as coatings for high frequency electrodes. The current density distribution at 50 kHz at the electrode–electrolyte interface was also modeled to demonstrate the importance of the primary current distribution in supporting charge injection at high frequencies. Approach. We determined electrode polarization in response to sinusoidal currents with frequencies in the 1–50 kHz range and current amplitudes from 100 to 500 µA and 1–5 mA, depending on the electrode area. The current density distribution at the interface was modeled using the finite element method (FEM). Main results. At low frequencies, 1–5 kHz, polarization on the platinum electrode was significant, exceeding the water oxidation potential for high amplitude (5 mA) waveforms. At frequencies of 20 kHz or higher, the polarization was less than 300 mV from the electrode open circuit potential. The choice of electrode material did not play a significant role in electrode polarization at frequencies higher than 10 kHz. The current density distribution modeled at 50 kHz is non-uniform and this non-uniformity persists throughout charge delivery. Significance. At high frequencies (>10 kHz) electrode double-layer charging is the principal mechanism of charge-injection and selection of the electrode material has little effect on polarization, with platinum, iridium oxide, and titanium nitride exhibiting similar behavior. High frequency stimulation is dominated by a highly nonuniform primary current distribution.

Comparative study of active plasma lenses in high-quality electron accelerator transport lines

Electrically discharged active plasma lenses (APLs) are actively pursued in compact high-brightness plasma-based accelerators due to their high-gradient, tunable, and radially symmetric focusing properties. In this manuscript, the APL is experimentally compared with a conventional quadrupole triplet, highlighting the favorable reduction in the energy dependence (chromaticity) in the transport line. Through transport simulations, it is explored how the non-uniform radial discharge current distribution leads to beam-integrated emittance degradation and a charge density reduction at focus. However, positioning an aperture at the APL entrance will significantly reduce emittance degradation without additional loss of charge in the high-quality core of the beam. An analytical model is presented that estimates the emittance degradation from a short beam driving a longitudinally varying wakefield in the APL. Optimizing laser plasma accelerator operation is discussed where emittance degradation from the non-uniform discharge current (favoring small beams inside the APL) and wakefield effects (favoring larger beam sizes) is minimized.

Effect of the design parameters on mass transfer and energy consumption inside a lithium electrolysis cell

A 2D axisymmetric electrochemical model of a lithium experimental cell is solved using a finite element method. The model is considering the coupled effect of momentum, electric, kinetic and mass transfer phenomena. The dense diaphragm used in the setup, which is not hydraulically permeable, separates the cell into two regions: 1 (a) turbulent region, between the anode and the diaphragm, and 2 (a) laminar region between the diaphragm and the cathode. The k-epsilon model is used to solve the turbulent flow resulting from bubbles generation at the anode. A two-phase flow model is also developed to simulate the volume fractions of bubbles and electrolyte in the cell. The non-uniform bubbles distribution over the anode surface, derived from the non-uniform current distribution, has been added to the two-phase model. The effects of the diaphragm length, position and porosity on the electric and two-phase flow fields are simulated. In fact, the diaphragm position and length both influence the current distribution at the surface of electrodes and the velocity distribution in the cell, all of which influence ohmic and kinetic overpotentials. The results show that up to 40% of energy can be saved when running the lithium electrolysis cell with a shorter porous diaphragm located as far as possible from the anode. The maximum current density, found at the bottom corner of anode, is higher when the diaphragm is longer and when it is closer to the anode.