Influence Of Cell Design Research Articles

Influence of Cell Design and Gate-to-Source Voltage on Avalanche Robustness of SiC MOSFET Integrated JBS Diode

In this work, 1200 V SiC JMOS devices with different Wsch (2 μm, 2.5 μm and 3 μm) are fabricated. The single unclamped inductive switching (UIS) tests under different Vgs_off (-5 V and 0 V) are carried out to investigate the avalanche capability. The avalanche robustness among various Wsch under same Vgs_off is also compared and analyzed by simulation. The different failure mechanisms between different Vgs_off are studied by failure analysis and simulation. The method of improving avalanche ruggedness of JMOS is proposed.

Experimental investigation of the impact of mechanical deformation on aging, safety and electrical behavior of 18650 lithium-ion battery cells

Particularly in mobile applications, 18650 lithium-ion batteries can be exposed to mechanical abuse. Deforming mechanical abuse can severely damage the battery case, but sometimes without causing instantaneous cell failure. If such cases remain undetected, the cells may remain in use and pose a potential long-term safety hazard. Due to research gaps in the scientific literature regarding the long-term implications of such damage, the influence of cell design, intrusion depth, as well as the impact on the electrical behavior, two cyclic aging studies and further electrical tests (CC–CV capacity, DVA) were conducted with mechanically deformed 18650 cells; using CT, post-mortem, and SEM for further analysis. In the cyclic aging studies, both cell types tested (with a mandrel and mandrel-free) remained electrically functional and showed no safety–critical behavior, despite intrusions of up to 6mm. Cells with significant intrusion exhibited increased CC–CV charge capacity for one charging process, and CC-discharge capacity decreases of 3.2% after mechanical deformation, but no or only slightly accelerated aging rates after the initial capacity drop. DVA indicated a global capacity loss of useable material rather than specific anode or cathode damage. CT analysis revealed case re-deformation after cyclic aging, likely due to jelly roll swelling. Post-mortem analysis showed imprints on all electrode components and active material debonding. SEM analysis revealed changes in cell internal pressure distribution due to external deformation.

Influence of Cell Design on the Performance of Direct Ammonia-Fueled Solid Oxide Fuel Cell: Anode- vs. Electrolyte-Supported Cell

In this study, the performance of anode-supported and electrolyte-supported cells was compared under similar operating conditions for direct ammonia-fueled solid oxide fuel cell (SOFC); the cell configuration of both types of cells was as follows, Ni‒YSZ|YSZ|GDC|LSCF. The anode-supported cell showed better performance as compared with that of the electrolyte-supported cell. A power density of ca. 0.358 W cm-2 was achieved for the anode-supported cell at 700 oC, which was higher than that of the electrolyte-supported cell. Furthermore, the ohmic and polarization resistances were lower for anode-supported cell. This is because in the anode-supported cell, the thinner electrolyte layer is responsible for the reduced ohmic resistance and improved cell efficiency. The effect of humidity on the performance of both types of cells using NH3 and H2 fuels was studied. The experimental results indicated that in the case of ammonia fuel, a small amount of humidity (1.67% H2O) was beneficial for better performance. However, further increase in humidity caused cell performance degradation. The effect of humidity on the cell performance was further analyzed. The anode microstructure of both types of cells was investigated after 10 h of discharge operation at 0.2 A cm-2 at 700 oC using NH3 and H2 fuels under various humidified conditions. For the anode-supported cell, the surface of Ni particles was covered with the small-sized particles after discharge operation; the Ni particles on the anode surface coarsened significantly in the ammonia fuel as compared with the hydrogen fuel. This is because the anode surface is exposed to the gaseous mixture containing large amount of ammonia which may cause the nitridation of Ni particles. On the other hand, at the anode/electrolyte interface the extent of coarsening of Ni particles was almost similar regardless of the fuel. This can be explained by the fact that most of the NH3decomposes catalytically and thermally at the anode surface. Hence, the partial pressure of ammonia will be lower at the anode/electrolyte interface. In this study, it was found that the anode-supported design is suitable for direct-ammonia fueled SOFCs. In the case of anode-supported cells, the improvement in the performance and the stability can be expected by optimizing the operating conditions, such as the operating temperature and the steam concentration in the inlet gas. Acknowledgement This work was supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), “energy carrier” (Funding agency: JST).

Influence of Cell Design on the Performance of Direct Ammonia-Fueled Solid Oxide Fuel Cell: Anode- vs. Electrolyte-Supported Cell

In this study, the performance of anode-supported and electrolyte-supported cells was compared under similar operating conditions for direct ammonia-fueled solid oxide fuel cells (SOFCs); the cell configuration of both types of cells was as follows, Ni‒YSZ|YSZ|GDC|LSCF. The anode-supported cell (ASC) showed better performance as compared with that of the electrolyte-supported cell (ESC). The influence of the humidity of inlet gas on the performance of ASC was investigated at 700 oC. The cell performance did not change substantially under different humidified conditions. In addition, the long-term discharge operation of direct ammonia-fueled ASC was conducted at 600 oC for ca. 235 h. The durability of ASC under polarization was evaluated on the basis of the measured current-voltage and power density curves. The cell showed slight degradation in current density and power density after discharge operation. Furthermore, the formation temperature of Ni3N under ammonia-fueled SOFC conditions was investigated in detail.

Influence of cell design on impedance characteristics of cylindrical lithium-ion cells: A model-based assessment from electrode to cell level

Electrochemical impedance spectroscopy (EIS) is a fast, inexpensive and non-destructive tool for identification of electrical and electrochemical loss processes of battery cells in a wide range of frequencies. Among those, particularly interface processes like the migration of Li species through surface films and the charge transfer reaction are easy accessible by EIS. One of the main drawbacks of its application to commercial cells is the limitation to the full cell spectrum due to the absence of an appropriate reference potential to separate cathodic and anodic contributions. Further, the impedance response of cell geometries such as cylindrical cells is characterized by a complex superposition of contributions arising from electrochemistry and cell design. In this study, we address these issues by a planar transmission line model allowing to reconstruct the impedance response of cylindrical cells by impedance data obtained from three electrode measurements on extracted electrodes and geometrical information obtained from microscopical cross sections. The reconstruction results indicate a substantial contribution from the spiral geometry of the current collectors and the position of the current collector tabs along the jelly roll. Furthermore, the impedance response is significantly determined by the power/energy design of the cell, for instance by the ratio of electrode areas and thicknesses. Overall, the proposed methodology presents a sound modeling basis for a deeper understanding of the impedance response of cylindrical cells and a tool for cell design optimization from electrode to cell level.

Influence of Cell Design and Electrode Materials on the Decolouration of Dyeing Effluents

Influence of Cell Design and Electrode Materials on the Decolouration of Dyeing Effluents

Minimising heat losses during batch ohmic heating of solid food

The influence of cell design on the uniformity of batch ohmic heating of a solid foodstuff was examined. Various ways of minimising heat loss from the cell surface including insulation or providing supplementary heat via a heating belt or panel were assessed but discarded in favour of housing the cell in a hot air cabinet maintained at 80 °C and eliminating the surrounding cell body. Various electrode materials and designs were evaluated prior to opting in favour of platinised titanium electrodes of minimal practicable thickness (1 mm). The final system developed involved the use of a combined ohmic/convection heating with the food stuff contained in a plastic casing pressurised between two spring-loaded electrodes. Under optimised conditions a maximum overall temperature variation of 12.1 °C within the product was achieved after 150 s which was reduced to 8.6 °C after 3 min standing time.

Review of factors that affect the deep cycling performance of valve-regulated lead/acid batteries

The effects of compression, positive-grid growth, electrolyte stratification and uniformity across a series string of cells during deep-cycling service of valve-regulated lead/acid batteries are considered. Without adequate control, each of these will cause premature failure. Although substantial improvements in cycleability have been made in recent years, more understanding and optimization of these factors is necessary for further improvements. In particular, little is known about the changes in the properties of separators during service that effect compressive forces on the positive plate, and more knowledge is required on the influence of grid growth and on the influence of cell design on electrolyte stratification in valve-regulated batteries. In addition, the paper considers the progressive variation between cells in long series strings, which is a major cause of early failure of these designs.

Aspects of lead/acid battery technology 6. Designing for capacity

The factors that determine the capacity of a cell are reviewed and the influence of cell design on the end-of-charge specific gravity and attainable capacity is examined. The effect of predominantly deep or shallow discharging is assessed for cells with either flat or tubular positive plates. The contribution, or otherwise, of the various sections and components of a cell is evaluated and a detailed design breakdown is made for (i) a tubular positive plate cell rated at 100 Ah/plate and (ii) a flat positive plate cell rated at 66 Ah/plate. The effect of production tolerances on components is discussed and a method for estimating the probable spread in capacity for bulk production is described.

The influence of cell design and electrolysis parameters on the cathodic coupling of butadiene and carbon dioxide in acetonitrile. I. Undivided parallel plate configurations

The reduction of carbon dioxide in the presence of excess butadiene in acetonitrile leads to a mixture of carboxylic acids, pentenoic acids (two isomers), hexenedioic acids (two isomers) and decadienedioic acids (three isomers). The total current yield can exceed 60%. The current efficiency and the ratio of products are functions of both cell design and other electrolysis parameters. This paper reports studies of this coupling reaction in several undivided flow cells, where cyclindrical cathodes (lead-plated nickel gauze, reticulated carbon of various porosity, carbon felt) were surrounded by a platinum gauze anode. The electrolyte was ditetraethylammonium oxalate and/or tetraethyl-ammonium formate so that the counter electrode reaction was the oxidation of the anions to CO2 or CO2+H+, respectively. This choice avoids solvent decomposition or other unwanted reactions at the anode, and may be helpful to the cathode chemistry by replenishing the cathode active species, CO2, and possibly also creating a controlled supply of protons to the cathode.