Energy Storage Components Research Articles

Stable energy storage performance at high-temperature of PESU-based dielectric composite regulated by SiO2 and BNNSs

Polymer dielectric capacitors are essential components for energy storage in modern electronic devices. They offer several advantages, including excellent voltage resistance, easy processing, and great energy storage density (U). However, with high thermal and electric fields, the more conductivity losses of polymer dielectric materials can be generated and aggregated, and the discharge energy density (Ue) and charging-discharging efficiency (η) of dielectric capacitor are usually significantly lower than that at room temperature. Here, the state-of-the-art composite is proposed, in which the SiO2 filler with excellent insulation strength is introduced into the middle composite layer, and the composite introduced wide band-gap boron nitride nanosheets (BNNSs) is used as the outer composite layer to inhibit carrier migration and reduce leakage current density of composite. The experimental results illustrate that the Ue of 1BP/1SP/1BP dielectric composite reaches about 9.37 J/cm3, and the η is around 82.0 % under the electric field of 540 kV/mm at 80 °C. Significantly, the η of multilayer 1BP/1SP/1BP composite remained >95.0 % after 50,000 cycles, indicating that this multilayer composite has good cycle stability and excellent reliability under a high-temperature. It presents a practical approach to enhance the energy storage performance of dielectric polymer at high-temperature environment.

Deep reinforcement learning-based scheduling for integrated energy system utilizing retired electric vehicle battery energy storage

Retired electric vehicle batteries (REVBs) retain substantial energy storage capacity, holding great potential for utilization in integrated energy systems. However, the dynamics of supply and demand, alongside battery safety constraints, present challenges to the optimal dispatch of energy. This paper proposes a hybrid system including thermal and electric energy employing REVB as the energy storage component. This system relies on photovoltaics (PV) technology to harness solar energy and convert it into thermal and electrical energy for supplying users. The REVB, as the core component of the system, functions to regulate the allocation of energy by managing its charging and discharging behavior. To explore the optimal energy scheduling strategy, a two-stage deep reinforcement learning (DRL) optimization method is presented. In the first phase, a deep deterministic policy gradient (DDPG) method is introduced to determine the REVB's behavior, and in the second phase, a competitive bidding mechanism is presented to optimally distribute energy. Simulation results, validated with real scenarios and data, achieve a reduction of 35.2 % in energy dissipation and 4.6 % in users' expenditure for purchasing energy compared to standard strategy. Simultaneously, experiments have shown that REVB is nearly as efficient as new battery as energy storage component, with energy wastage only about 1.1 % higher and users' expenditure less than 1 % higher.

Hybrid microsupercapacitors based on Ti3C2Tx MXene and covalent organic frameworks

The growing demand for emerging electronic applications, including energy storage, sensors, and portable devices, has created a pressing need to develop miniaturized flexible energy storage components with convenient device architecture. Here, we report an in-plane hybrid micro-supercapacitor made of covalent organic frameworks and Ti3C2Tx MXene as positive and negative electrodes, respectively. The devices utilize three-dimensional laser-scribed graphene (LSG) as a current collector for both electrodes using a CO2-laser-based technique due to its good resolution for in-plane device fabrication, and high porosity of LSG that can facilitate better rate performance. The constructed hybrid supercapacitor has a maximum areal capacitance of 131.46 mF/cm2 and a voltage window of 1.2 V. The findings provide a new strategy to fabricate a hybrid supercapacitor for self-powered device applications at the microscale.

Robust Online Estimation of State of Health for Lithium-Ion Batteries Based on Capacities under Dynamical Operation Conditions

Lithium-ion batteries, as the main energy storage component of electric vehicles (EVs), play a crucial role in ensuring the safe and reliable operation of the battery systems through monitoring their state of health (SOH). However, temperature variations and battery aging have significant impacts on the internal parameters of lithium-ion batteries, and these changes directly correlate with the accuracy of battery SOH estimation. To address these issues, this paper proposes an estimation method for lithium-ion battery SOH that considers the impact of temperature. The method begins with reconstructing a second-order hybrid equivalent circuit model for lithium-ion batteries, through which an adaptive update rate for battery model parameters is designed. On this basis, a nonlinear observer for battery states is introduced by integrating filters to estimate SOH. The proposed method considers the impact of capacity in the design of the parameter adaptive update rate, enabling the capacity to be dynamically adjusted based on the actual state of the batteries. This reduces the cumulative error in the SOC observer and improves the modeling accuracy of battery models. Experimental results demonstrate that the method proposed in this paper exhibits exceptional performance in SOH estimation under different temperature conditions. The mean absolute error for SOH estimation does not exceed 0.5%, and the root mean square error does not exceed 0.2%. This method can significantly improve the estimation accuracy of SOH, providing a more efficient and accurate solution for battery management systems in EVs.

Design and operation of an adiabatic compressed air energy storage system incorporating a detailed heat exchanger model

Heat exchangers (HEXs) are among the key components of adiabatic compressed air energy storage (A-CAES) systems. However, the existing HEX models applied in the A-CAES systems are overly simplistic, limiting research regarding design and operational simulation. For the first time, this study incorporates a comprehensive HEX model, including calculations for geometric dimensioning, heat transfer, and pressure drop, into the A-CAES system model; in addition, a novel layered, interactive system design and operational simulation algorithms are developed. The developed models and algorithms can facilitate the design process and yield reasonable operational simulation results with only basic parameters. The design algorithm can determine all key parameters of the system and assess the effect of the HEX pressure drop and heat transfer area on the system performance. The operational simulation algorithm considers the performance of all key equipment under off-design conditions. The design exergy efficiency and daily net income of the system are 73.15 % and $26,998, respectively; however, these values decrease during operation to 72.15 % and $25,034, respectively. A comprehensive analysis of the key parameters during operation revealed that the primary causes for the degradation were the sliding pressure in the energy storage process and variations in the air storage tank parameters.

Excellent energy storage properties in ZrO2 toughened Ba0.55Sr0.45TiO3-based relaxor ferroelectric ceramics via multi-scale synergic regulation

Lead-free ceramic capacitors offer ultrahigh power density and ultrafast discharging rates, making them critical energy storage components for advanced pulsed power systems. However, the greatest obstacle to broader applications remains the relatively low energy storage density. In this study, a relaxor ferroelectric ceramic based on (0.6-x)Ba0.55Sr0.45TiO3-0.4Bi0.5Na0.5TiO3-xSrZrO3 ((0.6-x)BST-0.4BNT-xSZ) is prepared using the tape casting method, resulting in an excellent energy density (Wrec ≈ 10.0 J cm−3) and high energy storage efficiency (η ≈ 91 %). The solid solution of linear dielectrics SrZrO3 synergistically regulates both relaxor properties and breakdown strength. The variation of relaxor property was explored utilizing New Glass model and the multi-polarization model, with confirmation provided by piezoresponse force microscopy. Furthermore, the breakdown strength could be attributed to improvements in electric insulation and the widening of the bandgap. As SrZrO3 content increases, the in-situ emergence of the second phase ZrO2, accompanied by a martensitic transformation, not only improves the fracture toughness of ceramics but also serves to elongate the breakdown path. Encouragingly, x = 0.20 ceramics also achieve excellent temperature stability (−95–125 ℃), frequency stability (1–1000 Hz), cycling reliability (1–106 cycles), and great charging-discharging properties. This multiscale synergic regulation strategy plays a guiding role in the screening of high-performance energy storage dielectric materials.

Performance analysis on combined energy supply system based on Carnot battery with packed-bed thermal energy storage

Pumped-thermal electricity storage (PTES) is a promising energy storage technology with high-efficiency, energy density, and versatility of installation conditions. In this study, a 20 kW/5 h phase change packed-bed thermal energy storage experimental system is established and employed to validate the accuracy of thermal energy storage (TES) component within the broader PTES system. Moreover, a novel combined system based on latent TES is proposed, incorporating Joule-Brayton and organic Rankine cycle-based subsystems for supplying cold, heat, electricity, and hydrogen. Operational strategies are also explored to optimize the multifunctional capabilities of the system. The thermal energy density of the system, when phase change materials (PCMs) are used instead of sensible heat storage materials, can be improved from 167.85 kWh/m3 to 272.58 kWh/m3. Proton exchange membrane electrolyzer cycle (PEMEC) is coupled into the Carnot battery system, and a comprehensive analysis of the system's performance is conducted. With the charging time of 5 h, the energy performance of the multi-generation system (EPMG) can be reached up to 143 % and 146 % in combined cooling, heating, and power (CCHP) and multi-generation energy system (MGES) modes, respectively. The MGES mode is made 3.44 % more exergy efficient than the CCHP mode as a result of the ingenious coupling of the hydrogen production process with the power generation process and heating/cooling processes. The system in one charging/discharging process has the capability to generate 240.86 kg of hydrogen, 34.82 MWh of heat, 12.97 MWh of cold, and 40.90 MWh of electricity.

Integrated life cycle assessment in off-grid energy system design—Uncovering low hanging fruit for climate mitigation

We perform an ex-ante life cycle assessment, integrating cradle-to-gate greenhouse gas emissions into an off-grid energy system model. By applying a multi-objective optimization, minimizing both costs and carbon dioxide equivalent (CO2e) emissions, we find the Pareto boundary between these two goals. As a case study, we chose the power supply to an astronomical observatory in Chile, using mostly solar power and energy storage in batteries and hydrogen. We compare the ex-ante study to a prior ex-post life cycle assessment, and furthermore dive into sensitivities of our model regarding component lifetimes and costs. We find (i) low-hanging fruit in lowering emissions with small cost increases, (ii) ex-ante life cycle assessments’ possibility to find less CO2e intensive power systems compared to ex-post conducted studies, (iii) a pronounced sensitivity of the optimization model on assumed lifetimes of energy storage components. This study shows the importance of including life cycle CO2e emissions into the optimization objective of energy system models. This method uncovers the environmental and economic trade-offs associated with high shares of renewable energies in off-grid energy systems.

Coordinated power management strategy for reliable hybridization of multi-source systems using hybrid MPPT algorithms

This research discusses the solar and wind sourcesintegration in aremote location using hybrid power optimization approaches and a multi energy storage system with batteries and supercapacitors. The controllers in PV and wind turbine systems are used to efficiently operate maximum power point tracking (MPPT) algorithms, optimizing the overall system performance while minimizing stress on energy storage components. More specifically, on PV generator, the provided method integrating the Perturb & Observe (P&O) and Fuzzy Logic Control (FLC) methods. Meanwhile, for the wind turbine, the proposed approach combines the P&O and FLC methods. These hybrid MPPT strategies for photovoltaic (PV) and wind turbine aim to optimize its operation, taking advantage of the complementary features of the two methods. While the primary aim of these hybrid MPPT strategies is to optimize both PV and wind turbine, therefore minimizing stress on the storage system, they also aim to efficiently supply electricity to the load. For storage, in this isolated renewable energy system, batteries play a crucial role due to several specific benefits and reasons. Unfortunately, their energy density is still relatively lower compared to some other forms of energy storage. Moreover, they have a limited number of charge–discharge cycles before their capacity degrades significantly. Supercapacitors (SCs) provide significant advantages in certain applications, particularly those that need significant power density, quick charging and discharging, and long cycle life. However, their limitations, such as lower energy density and specific voltage requirements, make them most effective when combined with other storage technologies, as batteries. Furthermore, their advantages are enhanced, result a more dependable and cost-effective hybrid energy storage system (HESS). The paper introduces a novel algorithm for power management designed for an efficient control. Moreover, it focuses on managing storage systems to keep their state of charge (SOC) within defined range. The algorithm is simple and effective. Furthermore, it ensures the longevity of batteries and SCs while maximizing their performance. The results reveal that the suggested method successfully keeps the limits batteries and SCs state of charge (SOC). To show the significance of system design choices and the impact on the battery’s SOC, which is crucial for the longevity and overall performance of the energy storage components, a comparison in of two systems have been made. A classical system with one storage (PV/wind turbine/batteries) and the proposed system with HESS (PV/wind turbine system with batteries). The results show that the suggested scenario investigated with both wind and solar resources appears to be the optimum solution for areas where the two resources are both significant and complementary. The balance between the two resources seems to contribute to less stress on storage components, potentially leading to a longer lifespan. An economical study has been made, using the Homer Pro software, to show the feasibility of the proposed system in the studied area.

A Novel SVM Strategy to Reduce Current Stress of High-Frequency Link Matrix Converter

High-frequency link matrix converter (HFLMC) can directly realize DC/AC conversion without intermediate energy storage components, reduce the power conversion stage, and improve efficiency and power density. With the conventional space vector modulation strategy, the secondary side voltage of the high-frequency transformer presents an asymmetric trapezoidal wave, which leads to the DC magnetic bias phenomenon and increases the current stress in secondary side switches. This paper proposes a novel SVM strategy for HFLMC. It optimizes the space vector distribution, makes secondary side voltage periodic and symmetric, and reduces the switching actions. The current stress is reduced, and the converter's efficiency is improved. Simulation and experiment results verify the advantages of the proposed modulation strategy.

A Symmetric Sixth-Order Step-Up Converter with Asymmetric PWM Achieved with Small Energy Storage Components

This research explores an improved operation of a recently studied converter, the so-called two-phase sixth-order boost converter (2P6OBC). The converter consists of a symmetric design of power stations followed by an LC filter; its improved operation incorporates an asymmetric pulse width modulation (PWM) scheme for transistor switching, sometimes known as an interleaved PWM approach. The new operation leads to improved performance for the 2P6OBC. Along with studying the 2P6OBC, one of the contributions of this research is providing design equations for the converter and comparing it versus the interleaved (or multiphase) boost converter, known for its competitiveness and advantages; the single-phase boost topology was also included in the comparison. The comparison consisted of a design scenario where all converters must achieve the same power conversion with an established maximum switching ripple, and then the stored energy in passive components is compared. Although the 2P6OBC requires a greater number of components, the total amount of stored energy is smaller. It is known that the stored energy is related to the size of the passive components. Still, the article includes a discussion of this topic. The new operation of the converter offers more streamlined, cost-effective, and efficient alternatives for a range of applications within power electronics. The final design of the 2P6OBC required only 68% of the stored energy in inductors compared to the multiphase boost converter, and 60% of the stored energy in capacitors. This result is outstanding, considering that the multiphase boost converter is a very competitive topology. Experimental results are provided to validate the proposed concept.

The recycling and utilization of new energy batteries

As the main energy storage component of new energy vehicles, the retirement tide of power batteries is coming. The large-scale retirement of power batteries has brought huge benefits to the treatment of power batteries challenge. From the aspects of environment, resources and economy, the significance of power battery recycling is expounded, and the current status of power battery recycling is analyzed. It is aimed at strengthening new energy vehicles power battery recycling, from the aspects of improving laws and regulations, improving the recycling system and improving recycling technology, put forward countermeasures and suggestions. At present, the main technologies are mechanical separation technology, pyrolysis technology and wet extraction technology. Mechanical separation technology mainly uses vibration separation, eddy current separation and electrostatic separation methods to separate different substances in the battery. Pyrolysis technology refers to the heating of waste to a certain temperature in an oxygen-free or low-oxygen environment to decompose organic matter, gas, liquid and solid products. The pyrolysis technology method mainly recovers heavy metals such as nickel and zinc, and the recovery efficiency is high. However, air participation in the operation is easy to cause secondary pollution. Wet extraction technology mainly extracts valuable materials and valuable heavy metals through sorting and sorting, shelling, dissolving in acid and alkali solutions, extraction and ion exchange methods. This technology has a wide range of applications, high recycling rate and little impact on the environment, and is currently one of the mainstream technologies in the field of new energy vehicle battery recycling. However, the process is complex and lengthy, and the recovery of electrolyte and leaching residue is easy to cause secondary pollution, and the recovery cost is high.

Fabrication and evaluation of polyurethane supported form‐stable PCMs

AbstractThe current research is oriented towards the development and assessment of the properties of the form‐stable phase change materials (PCMs), comprising of the thermoset polymer matrix (polyurethane, PU) enclosing capric acid (CA) as an active thermal energy storage (TES) component. The Fourier Transform Infrared Spectroscopy (FTIR) and Field‐Emission Scanning Electron Microscopy (FE‐SEM) have been used to characterize the chemical nature and morphological details of the developed PU‐based PCMs (PUPCMs). TES attributes and thermal stability of the resultant PCMs are evaluated by thermo‐analytical techniques such as Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). A thermal reliability test has been conducted to determine the phase change efficiency of the prepared PCMs. PUPCMs have been found to be suitable for TES applications, such as passive space heating or cooling building applications.

Evaluation of the thermal capacity of cement-based thermal energy storage components. A case study

In this paper, we evaluate the heat capacity performance of cement-based heat exchangers for thermal energy storage and analyze their structural integrity under elevated temperatures. Fluid flow is modeled using the Navier-Stokes equations, conservation of mass, and energy. The response of the cement-based material is modeled considering thermomechanical coupling, obtaining the temperature profile within the thermal energy storage. This study allows us to observe the thermal energy storage capabilities for different thermal energy storage designs: plain concrete and concrete with nanoparticles of SiO2. Finally, we use our model for the evaluation of the concrete thermal energy storage component, which has been previously functionalized for use in low to medium temperature ranges (i.e., 100 °C to 400 °C).

A Load-Adaptive Driving Method for a Quasi-Continuous-Wave Laser Diode.

A quasi-continuous-wave (QCW) laser diode (LD) driver is commonly used to drive diode bars and stacks designed specifically for QCW operations in solid-state lasers. Such drivers are optimized to deliver peak current and voltage pulses to LDs while maintaining low average power levels. As a result, they are widely used in laser processing devices and laser instruments. Traditional high-energy QCW LD drivers primarily use capacitors as energy storage components and pulsed constant-current sources with op-amps and power metal-oxide-semiconductor field-effect transistors (MOSFETs) as their core circuits for generating repeated constant-current pulses. The drawback of this type of driver is that the driver's output voltage needs to be manually adjusted according to the operating voltage of the load before use to maximize driver efficiency while providing a sufficient current. Another drawback is its inability to automatically adjust the output voltage to maintain high efficiency when the load changes during the driver operation. Drastic changes in the load can cause the driver to fail to function properly in extreme cases. Based on the above traditional circuit structure, this study designed a stability compensation circuit and realized a QCW LD driver for driving a GS20 diode stack with a maximum repetition rate of 100 Hz, a constant current of approximately 300 A, a load voltage of approximately 10 V, and a pulse width of approximately 300 μs. In particular, a high-efficiency, load-adaptive driving method was used with the MOSFETs in the critical saturation region (i.e., between the linear and saturated regions), controlling its power loss effectively while achieving maximum output current of the driver. The experiments demonstrated that the driver efficiency could be maintained at more than 80% when the load current varied from 50 to 300 A.

Preparation of ultra-thin copper–aluminum composite foils for high-energy–density lithium-ion batteries through synergistic electroless plating and electroplating

Copper-aluminum composite foils have the advantages of excellent electrical and mechanical properties, lightweight, and low cost. However, overcoming the equipment limitations of physical preparation methods to produce ultra-thin copper–aluminum composite foils with outstanding properties has been a challenge. Herein, smooth-faced, dense, and tightly bonded copper–aluminum composite foils are prepared using a combination of electroless plating and electroplating. This process involves the use of tin and nickel as transition layers, followed by electroplating the copper-clad layer. Ultra-thin copper–aluminum composite foils with a copper layer thickness ranging from 0.5 to 7 μm and a minimum square resistance of 4.6 mΩ can be prepared with a mass of 36.7 %-70 % of that of pure copper foils of the same thickness. These foils are expected to be used in a variety of energy storage components that require extreme lightweight.

Grid Integration for Electric Vehicles: A Realistic Strategy for Environmentally Friendly Mobility and Renewable Power

The promotion of electric vehicles (EVs) as sustainable energy sources for transportation is advocated due to global considerations such as energy consumption and environmental challenges. The recent incorporation of renewable energy sources into virtual power plants has greatly enhanced the influence of electric vehicles in the transportation industry. Vehicle grid integration offers a practical and economical method to improve energy sustainability, addressing the requirements of consumers on the user side. The effective utilisation of electric vehicles in stationary applications is highlighted by technological breakthroughs in the energy sector. The continuous advancement in science and industry is confirming the growing efficiency of electric vehicles (EVs) as virtual power plants. Nonetheless, a thorough inquiry is imperative to elucidate the principles, integration, and advancement of virtual power plants in conjunction with electric automobiles, specifically targeting academics and researchers in this field. The examination specifically emphasises the energy generation and storage components used in electric vehicles. In addition, it explores several vehicle–grid integration (VGI) configurations, such as single-stage, two-stage, and hybrid-multi-stage systems. This study also considers the various types of grid connections and the factors related to them. This detailed investigation seeks to offer insights into the various facets of incorporating electric vehicles into virtual power plants. It takes into account technology improvements, energy sustainability, and the practical ramifications for users.

Low‐Temperature Flexible Integration of All‐Solid‐State Thin‐Film Lithium Batteries Enabled by Spin‐Coating Electrode Architecture

AbstractMicro energy sources as the nucleus of intelligent microdevices guarantee their full autonomy in the dimensions of time and space. However, the state‐of‐the‐art micro energy storage components, like all‐solid‐state thin‐film microbatteries (ASSTFBs), whose direct integration is impeded by the stereotyped vacuum‐based manufacturing technologies, for which an inevitable high‐temperature annealing step (> 500 °C) can exert catastrophic effects on the attached microdevices during the crystallization of manufactured insertion thin‐film cathodes, especially in flexible integration. Herein, a prototype construction is created to benchmark concrete feasibility for the low‐temperature manufacturing of ASSTFBs via a nonvacuum‐based spin‐coating electrode architecture. Results show that the spin‐coated LiFePO4 films enable low‐temperature (≈ 45 °C) manufacturing of ASSTFBs, by which it can deliver excellent cycling performance up to 1000 cycles. Importantly, this technology presents the versatility of integrating various cathode composites into ASSTFBs and is therefore generalized to the LiCoO2‐ and Li4Ti5O12‐based solid‐state chemistries. Furthermore, ASSTFBs with such compliant electrodes manifest outstanding flexibility without pronounced capacity degradation by successfully integrating on flexible temperature‐sensitive substrates. The spin‐coating protocol provides a general solution for excessive processing temperatures and ample opportunities for the development of on‐chip integratable and flexible ASSTFBs.

Programming Polarity Heterogeneity of Energy Storage Dielectrics by Bidirectional Intelligent Design.

Dielectric capacitors, characterized by ultra-high power densities, are considered as fundamental energy storage components in electronic and electrical systems. However, synergistically improving energy densities and efficiencies remains a daunting challenge. Understanding the role of polarityheterogeneity at the nanoscale in determining polarization response is crucial to the domain engineering of high-performance dielectrics. Here, a bidirectional design with phase-field simulation and machine learning is performed to forward reveal the structure-property relationship and reversely optimize polarity heterogeneity to improve energy storage performance. Taking BiFeO3-based dielectrics as typical systems, this work establishes the mapping diagrams of energy density and efficiency dependence on the volume fraction, size and configuration of polar regions. Assisted by CatBoost and Wolf Pack algorithms, this work analyzes the contributions of geometric factors and intrinsic features and find that nanopillar-like polar regions show great potential in achieving both high polarization intensity and fast dipole switching. Finally, a maximal energy density of 188 J cm-3 with efficiency above 95% at 8 MV cm-1 is obtained in BiFeO3-Al2O3 systems. This work provides a general method to study the influence of local polar heterogeneity on polarization behaviors and proposes effective strategies to enhance energy storage performance by tuning polarity heterogeneity.

A Layered Parallel Equaliser Based on Flyback Transformer Multiplexed for Lithium-Ion Battery System

An effective equaliser is crucial for eliminating inconsistencies in the connected serial batteries and extending the life of the battery system. The current equalisers generally have the problems of low equalisation efficiency, slow equalisation speed, and complex switching control. A layered parallel equaliser based on a flyback transformer multiplexed for a lithium-ion battery system is proposed. The equaliser employs both hierarchical and parallel equalisation techniques, allowing for simultaneous processing of multiple objectives. This enhances both the efficiency and speed of the equalisation process. The efficiency of equalisation can be further improved by implementing PWM control with deadband complement. Additionally, the flyback transformer serves as an energy storage component for both layers of the equalisation module, resulting in a significant reduction in the size and cost of the equaliser. The circuit topology of the equaliser is presented, and its operational principle, switching control, and equalisation control strategy are analysed in detail. Finally, an experimental platform consisting of six lithium-ion batteries is constructed, and equalisation experiments are conducted to verify the advantages of the proposed equaliser in terms of equalisation speed, efficiency, and cost.