Lead-acid Battery System Research Articles

Quantitative analysis of the material, energy and value flows of a lead-acid battery system and its external performance

The comprehensive optimization of lead-acid battery system (LABS) can promote the relationship between the development of human-socio-economic system and environment. Based on the lead anthropogenic cycle, LABS is divided into four stages: production of primary lead (PPL), fabrication and manufacture (F&M), use and waste management and recycling (WM&R). According to the relationship between LABS and external environment, a framework is developed for the coupling of composite flow (material flow, energy flow and value flow). The quantitative relations between external performance indicators (lead ore consumption, scrap lead emissions, energy consumption and increase in value) and the internal factors are established, and key factors that affect external performance and their impact level are identified. The results of Chinese LABS in 2014 indicate that the external performance of the material flow reduced as the decrease of the emission rates of PPL (γ1), F&M (γ2) and WM&R (γ4) and the increase of the large recycling rate (ατ) and production ratio. The impact level of the former three was 1.5–2.2 times higher than those of the latter two. γ2, γ4 and ατ had the higher impact level on energy consumption in descending order. The impact level of the emission rates was 2.0–3.0 times higher than that of the recycling rate. γ4, ατ, γ1, γ2, in descending order, were the four higher factors that affected the increase in value, and the impact levels of the farmer two were 1.5–2.0 times higher than those of the latter two. Moreover, γ4 and γ2 were the factors that influenced the whole external environment greater. The decreasing order of influence degree of the above factors on the external performance indicators was increase in value, energy consumption and the external performance indicators of material flow. The impact from coupling coefficients between energy, value and material on external performance is less than the above factors.

Low Defect Planar Graphene Exfoliation By Sonication in Polypropylene Carbonate and 5 Sec Microwaving

This is an exceptional process on low cost, low defect and high-quality graphene which is produced by sonication in PPC and microwaving for just 5sec. Low energy arc-discharging process expands electrolytic graphite rods into hierarchical-like 3D-graphene retaining the basal plane carbon crystalline order and chemical purity [1-2]. Sonication in Polypropylene Carbonate causes non-covalent PPC-π bonding at graphene basal plane, aligning the graphene sheets in directions that allows efficient transmission of cavitation pressures and exfoliation; while microwave treatment for 5s separates any layered graphene, utilizing thermally induced lattice vibrations without changes on surface properties. Produced graphene (XRD 2θ = 26 ⁰C) has low defect (0.05 < ID/IG < 0.2), retainment of chemical purity (0~2.5% O2 content), with optimized effective graphene sizes (ranging from 350nm to 35 um), for diverse applications, dispersibility in diverse solvent, conformability to flat semi-transparent surfaces; storable in concentrated slurry (>50 mg mL−1). Planar graphene is suitable as 2D electronic materials applications [3], composites [4] and energy materials applications [5-10]. Keywords: Arc Discharge, Sonication, Microwave, Exfoliation, Planar, XRD, HR-SEM, HR-TEM. O.J. Dada, " In-Situ Electrochemical Functionalization of Reduced Graphene Oxide: Positive Lead Acid Case. " ECS Trans., vol. 66, no. 14, pp. 19–30, Aug. 2015O.J. Dada, “ In-Situ Electrochemical Functionalization of Reduced Graphene Oxide: Positive Lead Acid Case.,” ECS ., MA2015-01 (870), April 2015.O.J. Dada and D. Villaroman, " Superior Electronic and Dielectric Properties of Corrugated ElectrochemicallyReduced Graphene over Graphene Oxide Papers " Journal of the Electrochemical Society, vol 166 no.2, pp D1-D16, 2019.O.J. Dada, " Functional Cathodic and Anodic Transition of Graphene Oxide Paper in Lead Acid Battery System and Its Electrochemistry ". Materials Today: Proceedings”, vol. 3, no. 8, 2688-2697, 2016.O.J. Dada, " Interconnected Graphene Networks as Novel NanoComposite for Optimizing Lead Acid Cathode ". IEEE NANO 2015- Int. Conf. Nanotechnology, Rome, 2015.O.J. Dada, " Higher Capacity Utilization and Rate Performance of Lead Acid Battery Electrodes Using Graphene Additives ”. Journal of Energy Storage, vol. 23, pp579-589, Jun. 2019.O.J. Dada, " Effect of the Size and Conductivity of Tailored Graphene Electro-Catalysts, Lead Acid Battery Cathode as a Case ". IEEE NANO 2015- Int. Conf. Nanotechnology, Rome, Italy, 2015.O.J. Dada, " Wrinkled Graphene Oxide Synthesis by Electrolytic Arc Discharge of Graphite Rods and Slightly Modified Hummer’s Process ". Available at SSRN 3368351, 2019.O.J. Dada, " Highly Ordered Commercial Graphene Manufactured from 3 Simple Steps ". Available at SSRN 3335369, 2019.O.J. Dada, " Low Defect Planar Graphene Exfoliation by Sonication in Polypropylene Carbonate and 5 sec Microwaving ". Available at SSRN 3386581, 2019.O.J. Dada, " Utilization of Hard Carbon as a Substitute for Graphite As Efficient Lithium Battery Anode Material ". Available at SSRN 3368403, 2019.O.J. Dada, “ High Performance Lithium Battery Anodes from Non-Water based Graphene ”. Available at SSRN 3368433, 2019.O.J. Dada, “ Free Standing Porous Graphene and Reduced Graphene Papers Manufactured from Sedimentation of Arc Discharge of Graphite Rods ”. Available at SSRN 3481786, 2019.O.J. Dada, " Corrigendum to “Higher capacity utilization and rate performance of lead acid battery electrodes using graphene additives” . Journal of Energy Storage, vol. 23, pp579–589, Jun. 2019.

Influence of discharge current on 3 cells dynamic lead-acid batteries performance

Lead-Acid Battery (LAB) is a secondary type battery that can work on static and dynamic electrolyte treatments. Dynamic batteries are a popular type of wet batteries recently due to high capacity storage, long life cycles, and simple designs. Dynamic Lead-Acid batteries have been chosen for this study to explore the characteristics of a lead-acid battery system consisting of 3 cells, 30% H2SO4 and a peristaltic pump. Twenty cycles of charge-discharge tests were carried out with a constant charging current of 1A until fully charged and the discharge current with variations of 0.2A; 0.3A; 0.4A and 0.5A. Experiments show that a smaller discharge current results in a longer duration of electric discharge. The cycle duration, capacity, and efficiency have decreased proportionally to the increase in the number charge-discharge cycles. Batteries with 0.2 A discharge current have shortest battery life. Batteries with 0.5 A discharge current have the greatest capacity performance.

Techno-Economical Feasibility of Biocellulose Membrane along with Polyethylene Film as a Separator for Lead-Acid Batteries

In this present investigation, we applied an eco-friendly bacterial cellulose (BC) membrane along with a polyethylene (PE) separator as a separator for lead-acid battery systems. The key factor of the research is to lower the cost of the lead-acid battery by introducing the BC membrane along with a thin PE separator. The specific surface areas of the BC membrane and the PE separator were 46.72 and 35.89 m2 g–1, respectively, with high porosity, which can enhance the electrolyte uptake and movement. The identified pore sizes of the BC membrane and the PE separator are 13.67 and 56.18 nm, respectively. The closely arranged microfibrils in the BC membrane with the smaller pore size can uptake a high amount of electrolyte, and it can hold it for a long period with the hydrogen interactions. In addition, the BC membrane and the PE separator exhibited higher thermal stabilities. The water uptake property of the BC membrane is 130% at 30 °C, which results in considerable electrolyte uptake. The ion exchange capa...

Evaluation of Grid-Connected Micro-Grid Operational Strategies

Abstract This study investigates the operational performances of a grid-connected microgrid with integrated solar photovoltaic and battery energy storage. The study is based upon the techno-economic specifications and theoretical performance of the distributed energy resource and storage systems, as well as on measured consumer load data and electrical utility retail and distribution data for representative residential and commercial loads for the city of Vasteras, Sweden. The open-source Matlab®-based simulation tool, OptiCE, is used for performing simulations and optimization. To support the attainment of one of the objectives, peak shaving of the consumer load, a battery operational strategy algorithm has been developed to balance peak shaving and PV self-consumption. Comparisons among three types of battery, lead-acid, lithium-ion and vanadium-redox flow, are also performed. A 117 kWp photovoltaic system paired with a lithium-ion battery of 41.1 kWh capacity is the optimal solution found for the considered commercial load. The calculated battery capacity represents the best trade-off for the set multi-objective optimization problem. The simulation of this system predicts the possibility to shave the customer load profile peaks up to 20% for the month of April. The corresponding self-consumption ratio is 88%. Differences in the relationship between the load profiles and the system performance have been qualitatively noted. Furthermore, the simulation results for lead-acid, lithium-ion and vanadium-redox flow battery systems reveal that lithium-ion batteries delivers the best trade-off between total annualized cost and peak shaving performance for both residential and commercial applications.

High charge acceptance through interface reaction on carbon coated negative electrode for advanced lead-carbon battery system

In this research, the interfacial effect between the carbon layer and the negative electrode surface is evaluated as a hybrid electrode with higher charge acceptance for the advanced lead-carbon battery (ALC-battery) system. The P-60 (activated carbon) material, with high specific surface area (1787 m2 g−1) and higher electrical conductivity (98.85 S cm−1), is considered an efficient activated carbon in the present investigations and deposited on the negative electrode. Compared to the conventional lead-acid battery system, the carbon coated negative electrode of ALC-battery system exhibited higher capacity at the applied higher charge/discharge current. The efficient performance of the ALC-battery is mainly influenced by the thin layer of carbon on the active electrode surface, which induces higher charge acceptance. Furthermore, the ALC-battery showed an outstanding lifespan performance compared to the conventional lead-acid battery system in long-term operations. The resulting cycle life stability of lead-acid battery and ALC-battery is 2230 and 6780 cycles, respectively. The significant performance of the ALC-battery is mainly attributed by synergistic mechanism in hybrid electrode, which is resulted from interfacial effect. The likely synergetic reactions arises by carbon layer is (i) higher charge acceptance, (ii) controlled the formation of PbSO4 crystallite in the electrode surfaces, (iii) improved electrochemical performances and Pb redox reaction due to higher electrical conductivity properties. Thus, it can be concluded that the carbon layer deposited on the negative electrode in the ALC-battery is an efficient approach for energy storage, with increased power, capacity, and enhanced cycle life stability.

A Multi-Stage Approach to a Hybrid Lead Acid Battery and Supercapacitor System for Transport Vehicles

Lead Acid Batteries (LABs) are used for starting, lighting, and igniting, as well as in air conditioning systems and to supply power to electric engines in transport vehicles (TVs). However, the application of LABs for TVs has faced a number of market challenges, mounted by the upcoming high energy density and long lifespan batteries, such as lithium ion. LABs, on the other hand, are inexpensive. The key research question is, how can the lifespan of LABs used in automotive industries be increased, while still ensuring a low cost solution? Thus, integrating LABs with the supercapacitor (known as an electric double layer capacitor—EDLC) is likely to outperform the competing alternative batteries for TVs. This paper proposes a multiple stage approach to hybrid lead acid batteries and a supercapacitor system for TVs that is capable of maintaining the battery state-of-charge (SOC) at statistically high limits, ranging between 90% and 95%. This SOC target will likely ensure that the lifespan of the hybrid battery system can be elongated (extended) more than its competitors. In this study, the multiple stage approach of concatenated converters has been designed in order to satisfy all energy storage requirements for different characteristics of LABs and the supercapacitor. The designed hybrid system has been simulated using Matrix Laboratory (MATLAB/Simulink (version R2016a, MathWorks, Natick, MA, USA)). The simulated results show that high transient currents from the direct current (DC) bus of LABs, caused by the regenerative braking or deceleration of the TVs, reduce the battery lifespan and induce mechanical stress. The supercapacitor reduces the stress on the LAB by absorbing high transient currents. This, in turn, keeps the LABs’ SOC between 90% and 96% and the voltage at 12 V. As indicated by the simulated results, the hybrid battery SOC is maintained at 90–96% and the terminal voltage is approximately 12 V.

Quantitative analysis of the coupling coefficients between energy flow, value flow, and material flow in a Chinese lead-acid battery system.

To reveal the historic characteristics of the material flow, energy flow and value flow in a lead-acid battery (LAB) system, a framework for the coupling relationship among the three flows was established based on material flow analysis and the characteristics of the energy and value flows. The coupling coefficients between energy and material (CCEM) and value and material (CCVM) were also defined. The investigation used by China as a case to study changes in stages and the historic evolution. The results show that the CCEM for lead in LABs was highest in the usage stage, approximately 5-16 times greater than in the other stages. The CCEM for production was almost twice as high for primary lead as for secondary lead, and the CCEM was lowest for the fabrication and product manufacture stage. The CCVM for lead in LABs was 2.5-6 times higher than for other types of lead. The CCVM was lower for scrap lead than for lead ore, and the CCVM was approximately 1.7 times higher for refined lead than for scrap and refined lead. For lead trade, CCVM was correlated with domestic and overseas markets. From 1990 to 2014, the CCEM for each stage was in decline, whereas the opposite was the case for CCVM. The influencing factors were analyzed in terms of resources, the environment, and markets. Increasing the circulation rate of scrap lead is an effective way to rapidly save resources, reduce lead pollution, and promote a circular economy. The limitations and potential value of the study are also highlighted, and future research is outlined.

Renewable energy integration through optimal unit commitment and electricity storage in weak power networks

ABSTRACTIn this work, the impact of intermittent renewable energy sources on total production cost is evaluated, using annual data regarding the isolated power system of the island of Cyprus. Once electrical energy storage (EES) is identified as an approach enhancing flexibility and reliability, the selected EES facilities are modelled and evaluated via a life-cycle cost analysis, based on the most realistic characteristics and cost metrics found in the literature. The results derived from the uncertainty analysis performed, show that vanadium-redox flow battery provides the highest net present value (NPV). However, sodium-sulfur battery system offers the most secure investment in terms of uncertainty range and mean value, followed by lead-acid battery system. Lithium-ion battery system exhibits expensive capital cost which still governs its overall cost performance achieving a negative mean NPV far below zero.

A Markov Decision Process for managing a Hybrid Energy Storage System

Abstract The high penetration of photovoltaic installations in the domestic sector and the clear reduction of the feed-in-tariffs have made the need for storage systems more and more imminent when greater amounts of energy ought to be daily allocated and assigned. Hybrid Energy Storage Systems (HESS) are a nascent technology which can contribute towards maximization of self-energy consumption and grid stability by smoothing out peaks. In the frame of this paper it is attempted to delimitate the capability of a HESS so as to support the domestic load demand of a single family house in a central north area in Germany, accumulated from the load demand of an E-vehicle which is used for commute reasons of the family and always charges at home. The designed HESS is composed of two storage devices, namely a lead acid battery system (LAB) and a Vanadium Redox Flow Battery (VRB), and supported also from a photovoltaic installation. So as to succeed an optimized utilization of the dual storage system a novel algorithm is developed based on the Markov Decision Process, according to which the priority for charging and discharging process is assigned to the storage facility which depicts a favorable performance under the respective given conditions. The performance of this algorithm is compared to a naive policy—a control strategy based on the constant prioritization of the LAB over the VRB due to LAB’s efficiency overperformance. Results demonstrate that with the proposed markov algorithm the system consumes annually almost 5% more from the on-site renewable production whereas less load peaks are noticed during grid exchange, compared to those extracted from the naive method. Furthermore, it is shown that during sunnier months results are more distinct in comparison to the naive policy (up to 9% increase in self-energy consumption and 3% reduction in grid fluctuations), due to higher power rating setting thus the designed algorithm as more suitable to coordinate the operation of the two storage devices.

Comparative Study of Energy Consumption for Electric Vehicles with Various On-board Energy Storage Systems

Electric vehicles are driven by traction motor with intermittent load characteristic. The use of appropriate batteries type is a crucial factor resulting in energy consumption, battery sizing and vehicle design. This paper focuses on the comparison of energy consumption of the electric vehicles in three different energy storage systems consisting of lead-acid battery, lithium-ion battery and hybrid energy storage system (HESS) incorporating with lithium-ion battery and ultracapacitor. The mathematical approach is used to simulate three route vehicle movement which are i) New York city cycle (NYCC), ii) UN/ECE reg. 83 or extra-urban driving cycle and iii) field measured driving profile in Bangkok. Sequential quadratic programming (SQP) is employed to find optimal weights of the energy storage system. The simulation results were consistent for all three routes. The lead-acid battery is heaviest weight but highest energy recovery from the regenerative braking and the energy consumption is greatly different from the others.

The Economic Feasibility of Residential Energy Storage Combined with PV Panels: The Role of Subsidies in Italy

A solar photovoltaic system produces electricity by converting energy from the sun. By the end of 2016, the global installed solar photovoltaic capacity reached 305 GW. Its growth is impressive in the last years; in fact, it was only equal to 41 GW in 2010. However, Europe has installed only 6.9 GW in 2016 (−1.7 GW in comparison to previous year) and this annual power installed is equal to 9% of global one in according to data released by Solar Power Europe. The profitability of PV systems in mature markets depends on the harmonization between demanded energy and produced one residential energy storage when combined with photovoltaic panels is able to increase the share of self-consumption. This work proposes a mathematical model, in which a Discounted Cash Flow analysis is conducted to evaluate the financial feasibility of photovoltaic-integrated lead acid battery systems in Italy. The indicator used is Net Present Value. Furthermore, a break-even point analysis, in terms of an increase of self-consumption, is conducted. The residential sector is investigated and energy storage system investment is incentivized by fiscal deduction and regional subsidies. The analysis provides several case studies, determined by combinations of the following variables: photovoltaic plant size, battery capacity, the increase of the share of self-consumption, and the useful lifetime of energy storage system. The same case studies are proposed also in four alternative scenarios, where is the modified the structure of subsidies. Results confirm that the profitability can be reached in presence of subsidies.

Novel core–shell structure of a lead-activated carbon (Pb@AC) for advanced lead–acid battery systems

To enhance the power and energy densities of advanced lead–acid batteries (Ad-LAB), a novel core–shell structure of lead-activated carbon (Pb@AC) was prepared and used as a negative electrode active material. The AC could be formed as a shell around a core of Pb nanoparticles. The active core–shell structures were synthesized using a simple chemical process to overcome the limitations in the negative Pb electrode, specifically the large crystallization of lead sulfate (PbSO4) that leads to a short cycle life. The key role of the carbon material in the negative electrode is to enhance the electrochemical performances and decrease the formation of PbSO4. The X-ray diffraction study reveals that the formation of lead oxide was prevented by the AC during the synthetic process. The novel core–shell structure of Pb@AC was confirmed through transmission electron microscopy. In order to obtain high-performance Ad-LAB, a high surface area of the AC is necessary to provide a super capacitive effect in the negative electrode. The unit cell performance of the as-prepared active materials exhibits significant increased discharge capacity at 1C rate. The unit cell with the Pb@AC negative electrode has a capacity per unit volume of 0.0165 Ah/cc. Hence, the low cost of AC and the simple synthetic core–shell structure of Pb@AC make this material a promising negative electrode active material for Ad-LAB applications.

Dynamic data-driven and model-based recursive analysis for estimation of battery state-of-charge

This paper addresses estimation of battery state-of-charge (SOC) from the joint perspectives of dynamic data-driven and model-based recursive analysis. The proposed SOC estimation algorithm is built upon the concepts of symbolic time series analysis (STSA) and recursive Bayesian filtering (RBF) that is a generalization of the conventional Kalman filtering. A special class of Markov models, called ×D-Markov (pronounced as cross D-Markov) machine, is constructed from a symbolized time-series pair of input current and output voltage. A measurement model of SOC is developed based on the features obtained from the ×D-Markov machine. Then, a combination of this measurement model and a low-order model of the SOC process dynamics is used for construction of the RBF. The proposed algorithm of SOC estimation has been validated on (approximately periodic) experimental data of (synchronized) current-voltage time series, generated from a commercial-scale lead-acid battery system.

Activated Carbon Modified Electrodes for Soluble Lead-Acid Flow Batteries

A soluble lead-acid flow battery (SLFB) system is a promising energy storage technology for its several economic advantages such as free of ion exchange membranes and inexpensive active materials. However, state-of-the-art SLFBs have limited cycle life, which hampers their commercialization. Shedding of lead dioxide (PbO2) at the graphite anode during charging/discharging cycles has been identified as one of the primary reasons for the degradation of SLFBs, since the shed lead dioxide could not be reversed for current extraction. In addition, oxygen evolution or other side reactions can occur when the SLFB is charged at higher rates, which in turn leads to lower coulombic efficiency and limits the flow battery for higher power applications. This study aims to extend the cyclability and increase the output power of SLFBs through modification of the graphite-based anode with activated-carbon addition. Activated carbon (AC) is known to have a high surface area and can perform capacitive behaviors when presents at the surface of an electrode during charge/discharge. Instantaneous current surge could thus be buffered when capacitive AC additives are employed in SLFBs. Moreover, addition of AC powders to a graphite electrode results in a higher total surface area per volume and will reduce local current densities. Since electroplating could induce dendrite formation because of surface instability, lower local current density could mitigate such instability and reduce shedding of PbO2 particles. Hence, the life time of SLFBs can be prolonged and the output power can be raised under the effects of AC additives. To determine the most effective portion of AC additives, long-term charge/discharge experiments are conducted. We find the addition of 0.5wt% activated carbon to the graphite anode extends the cycle life of our SLFB system up to over 300 times, as shown in Figure1. However, the columbic efficiency is obsevered to be reduced by around 5% in comparison to the electrode with no additives. In addition to the lower conductivity resulted from the residual metal and impurities, this reduced voltage efficiency of SLFBs may result from the hydrophobic nature of activated carbon materials. This issue could be compensated by increasing the hydrophilicity of activated carbon through pretreatment. Several strategies of pretreatments are taken to remove the impurities and enhance hydrophilicity. Our work demonstrates that longer cycle life and higher power output are possibile to be achived in SLFBs. Figure1. The charge/discharge efficiency of SLFBs with 0.5wt% activated carbon additive Figure 1

An MILP model for cost-optimal planning of an on-grid hybrid power system for an eco-industrial park

The application of on-grid hybrid power system (HPS) has been effective for harnessing renewable energy resources and ensuring environmental sustainability. A number of algebraic and mathematical modeling approaches have been introduced for the optimisation of on-grid HPS. While algebraic power pinch analysis (PoPA) tools have been developed to enable the selection of cost-effective energy storage technology, the available mathematical modeling approaches have yet to consider the economics and storage system selection in the design of an optimal on-grid HPS. This work presents a mixed-integer linear programming (MILP) for the optimal design of an on-grid HPS with the minimum net present value (NPV) of the overall electricity production cost and the selection of the optimum energy storage technology. Two case studies are presented in this work. In the former, the differences between the developed MILP model and previous methods are highlighted, with sensitivity analysis to investigate the impact of electricity tariff on the on-grid HPS. In the second case study, the developed MILP model was applied to an Eco-Industrial Park (EIP) case study with energy storage technology selection. Lead-acid battery system was found to be the optimal choice due to its low investment requirement.

Concept Design of 100-T Pulsed Magnet at the Wuhan National High Magnetic Field Center

A 100-T pulsed magnet with a bore size of 12 mm has been designed at the Wuhan National High Magnetic Field Center (WHMFC). This magnet consists of three coils. The inner coil will be wound from high-strength CuNb wire. The middle and the outer coils will be wound from copper wire. All the three coils will be reinforced with Zylon/epoxy composite. In order to increase the efficiency of the inner and the middle coils and reduce the coupling between them and the outer coil, the inner and the middle coils have a height of 400 mm, which is shorter than the 500-mm height of the outer coil. The inner and the middle coils are driven by 1.6- and 11-MJ capacitor banks, and the outer coil is driven by the combination of a 100-MJ/100-MW pulse generator and the 1000-V lead-acid battery system. At the peak field, the three coils contribute 47, 37, and 16 T, respectively.

Modified Activated Carbon Electrodes for Advanced Supercapacitors

The development of highly sophisticated portable electronic devices and the electro-mobility revolution, require new power sources with very high power density. Consequently, we see in recent years an accelerated development of super-capacitors of several kinds. These include electric-double layer (EDL) capacitors, based on purely electrostatic interactions, and the so-called pseudo-capacitors, which electrodes include surface red-ox species adsorbed to their surface within the porous structure and enhance the electrodes’ specific capacitance. The voltage (E) that can be applied to these devices is very important, because the energy density is proportional to E2. The potential applied depends on the electrolyte solutions used. Indeed, super-capacitors can be classified also according to the electrolyte solutions used and the potential applied. Using acidic or basic aqueous solutions enable to obtain fast electrostatic interactions at relatively high specific capacitance, but the potential applied is below 1V. Aqueous super-capacitors based on neutral solutions (e.g., electrolytes like Li2SO4) can operate at potentials >1.5V but their specific capacitance is lower compared to systems with acidic or basic solutions. The use of non-aqueous solutions enables to operate high voltage super/pseudo-capacitors, that may reach energy density of the same order of magnitude as that of aqueous rechargeable batteries (e.g. lead acid battery systems). In this presentation we present results related to super and pseudo capacitors that reflect novel approaches. We demonstrate how the use of red-ox species in solution phase which adsorb to porous carbonaceous electrodes can enhance the specific capacity of both aqueous and non-aqueous super-capacitors1. We will discuss what are the real limiting reactions of capacitive electrodes in non-aqueous solutions, including ionic liquids. In fact, possible intercalation of cations and anions at extreme potentials, into graphitic nano-crystallites that always exist in activated carbons is a major limiting factor in these systems, because such intercalation processes damage the structure of the activated carbon electrodes and lead to their degradation. In an another example, we demonstrate modification of high surface area activated carbon electrodes with 3D carbon nano-dots (C-dots). We explore these composite electrodes in supercapacitor ystems. For the first time, we propose herein the modification of activated carbon (AC) by a uniform deposition of highly crystalline carbon dots (C-dots) and used this novel material as electrode for supercapacitors. C-dots were synthesized by sonication of polyethylene glycol followed by sonochemical modification of AC matrices with the as prepared C-dots. We studied the sonochemical effect of the C-dots deposition into the AC and their incorporation into the pores. The porosity of the AC/C-dots and the reference AC materials and the impact of C-dots loading on the performance of electrodes comprising these AC/C-dots composites were explored. It was found that AC/C-dots electrodes demonstrate specific capacitance which is almost 3 times higher compared to that of unmodified AC electrodes. It was established that the new electrode material "activated carbon/carbon dots" exhibits very stable behavior. In all our durability experiments we test the electrodes along many thousands of cycles. We demonstrate herein highly stable , high capacity composite electrodes for super-capacitors with a Coulombic efficiency around 100%.

Effect of tariffs on the performance and economic benefits of PV-coupled battery systems

The use of batteries in combination with PV systems in single homes is expected to become a widely applied energy storage solution. Since PV system cost is decreasing and the electricity market is constantly evolving there is marked interest in understanding the performance and economic benefits of adding battery systems to PV generation under different retail tariffs. The performance of lead-acid (PbA) and lithium-ion (Li-ion) battery systems in combination with PV generation for a single home in Switzerland is studied using a time-dependant analysis. Firstly, the economic benefits of the two battery types are analysed for three different types of tariffs, i.e. a dynamic tariff based on the wholesale market (one price per hour for every day of the year), a flat rate and time-of-use tariff with two periods. Secondly, the reduction of battery capacity and annual discharge throughout the battery lifetime are simulated for PbA and Li-ion batteries. It was found that despite the levelised value of battery systems reaches up to 28% higher values with the dynamic tariff compared to the flat rate tariff, the levelised cost increases by 94% for the dynamic tariff, resulting in lower profitability. The main reason for this is the reduction of equivalent full cycles performed with by battery systems with the dynamic tariff. Economic benefits also depend on the regulatory context and Li-ion battery systems were able to achieve internal rate of return (IRR) up to 0.8% and 4.3% in the region of Jura (Switzerland) and Germany due to higher retail electricity prices (0.25CHF/kWh and 0.35CHF/kWh respectively) compared to Geneva (0.22CHF/kWh) where the maximum IRR was equal to −0.2%.

Control and Modelling of PV –Wind Hybrid Energy Sources for Desalination System

Hybrid renewable energy based on PV and wind systems complemented with battery storage system are starting to play a vital role over the world to supply power to distant regions. This paper proposes the combination of lead acid battery system with a typical hybrid PV-wind energy system for supplying the electrical load of a desalination system at Mersa Matrouh. Solar and wind are sources of energy and battery unit is considered as a storage unit to meet the load demand. Simulation model with MATLAB/Simulink for the hybrid power system has been developed considering power supply variation in solar and wind hybrid power system caused due to disturbed power supply from wind turbine generator and solar system. A control strategy using Neural Network Control (NNC) is being offered and analyzed. The final result of the simulation indicates an effective operation of battery. DOI: http://dx.doi.org/10.11591/telkomnika.v14i1.7650