Supercapacitor Module Research Articles

Design of a Supercapacitor Module and Control Algorithm for Practical Verification of a Hybrid Energy Storage System

This paper presents an approach to designing a supercapacitor (SC) module according to defined power profiles and providing a control algorithm for sharing the energy from the SC module and accumulator in a hybrid energy storage system (HESS). This paper also presents a view of a printed circuit board (PCB) of the SC module and an interconnection board between the bidirectional converter, accumulator, and SC module. The practical part of the paper presents the measurement of the voltages and currents on the SC module, accumulator, and output of the DC/DC converter to visualize the energy flow between them.

Negative Joule heat effect on supercapacitor module

Joule heat as the main heat source in high-power operation of supercapacitor modules, needs to be carefully considered in thermal management. The sufficient discussion on the temperature characteristics of supercapacitor modules, especially those containing auxiliary electronic components during operation is of importance. Here we reported the Joule heat effect on a supercapacitor module integrated on a circuit board in the charge and discharge cycles by an in situ Infrared imaging method. Temperature rise of total components including wires, circuit board, welding pint, resistor and capacitor cell could be simultaneously imaged with a sensitivity of 0.2–0.3 °C. Upon charge–discharge cycles from 5C-60C, Joule heat on these electronic components was discovered. The thermal transfered from the connected wires to the circuit board and finally to the cell, which significantly increased the temperature rise (from 9.3 °C to 19.6 °C at 60C) and temperature difference (9.6 °C at 60C) of different capacitors in modules. Further simulation results indicated that Joule heat on the circuit board was 2–3 times that of the capacitors in the module. Such additional heat flow without suitable cooling system would result an accelerated capacitance decay of the module. Therefore, a suitable module structure and thermal management strategy needed to be designed to minimize the Joule heat generation of such electronic components.

PVA-based Hydrogel Materials for Underwater Energy Storage and Underwater Sensing.

As human exploration of marine continues to expand, the demand for underwater devices is also increasing. The unique properties of hydrogel materials make them well-suited for underwater applications. We propose a multi-functional polyvinyl alcohol (PVA) - NaCl @ Polyaniline (PANI) (PNP) hydrogel, which is characterized by easy fabrication, integrated structure, and flexibility, and can be directly applied in the fields of underwater energy storage and underwater sensing. Solid-state supercapacitors fabricated by the PNP hydrogel, due to integrated and all-solid-state design, can be charged and discharged underwater without encapsulation. What's more, the PNP supercapacitor can maintain a capacitance retention rate of over 90% after 5,000 cycles in simulated seawater, eliminating concerns about the hydrogel's dehydration when used underwater. The PNP hydrogel with an integrated three-layer structure can also be applied to the capacitive pressure sensors, which can also be directly used in underwater environments without the need for encapsulation, significantly reducing the structural complexity and preparation steps of the device. Finally, we demonstrate a "supercapacitor module"with a voltage window greater than 1.6 V created by directly connecting multiple PNP supercapacitors in series, as well as an underwater intelligent glove, providing new solutions for underwater energy storage and underwater wearable sensing applications.

Design and optimization of air-cooled heat dissipation structure of an on-board supercapacitor box

An effective nonlinear optimization method is proposed for heat dissipation structure of the supercapacitor box in this paper. Supercapacitor has been widely used in modern tramcar for its fast charging and discharging, long cycle life and environmental protection. However, the large amount of heat generated during operation is difficult to be emitted, which hinders its further application. The existing studies mainly focus on the simulation of heat dissipation structure of lithium-ion battery pack, and there is relatively few literatures on simulation of supercapacitor module. This paper takes supercapacitor box of a tramcar as the research object. Firstly, a finite element model for heat dissipation is established. Then the heat dissipation characteristics are simulated. The spacings of the supercapacitor modules along x and y directions are optimized. The results show that the cooling effect is the best when the x-direction spacing is 120 mm, and y-direction spacing is 30 mm. The peak temperature is 312.22 K with a reduction of 1.5 %, and the temperature difference is only 3.24 K with a reduction of 12.4 %. Because the heat generation of supercapacitor modules is highly nonlinear, the mutation theory is used to optimize the heat dissipation structure. The results show that the best cooling effect is achieved when the air inlet is asymmetric and the out inlet is symmetric. The peak temperature is 310.15 K with a reduction of 2.2 %, and the temperature difference is 1.73 K with a reduction of 53.2 %. The results of this study could provide a scientific basis for the design of heat dissipation structure for the supercapacitor box.

Damage characteristic of electronic devices caused by products generated by Al/Ep/KMnO4/TiH2 active material projectile hypervelocity impacting on aluminum target

As the space environment becomes more competitive, space offense and defense are increasing every day. Projectiles made of reactive materials can achieve highly effective target destruction due to their good penetration, ignition and detonation capabilities as the kill element in space attacks. When a spacecraft encounters a hypervelocity impact from a projectile of active material, it will have a serious impact on the surface material and internal electronics (logic chips, super-capacitors, etc.), leading to anomalies in the spacecraft's on-orbit operation. In order to study the damage characteristics of internal typical logic chips and super-capacitor modules caused by the hypervelocity impact of active material projectiles on the surface of spacecraft, the simulated satellite experiment of Al/Ep/KMnO4/TiH2 active material projectiles hypervelocity impacting on aluminum target was performed. By using the self-built experimental loading system, plasma characteristic parameter diagnosis system, radiation temperature measurement system and electronic device function detection system, the characteristic parameters of plasma, light flash radiation temperature, temperature evolution process of logic chip and super-capacitor at specific position under different impact velocities are obtained. When the damage behavior of Al/Ep/KMnO4/TiH2 active material projectile impacts on the surface of simulated satellite, the main reasons affecting electronic devices and the damage characteristics of impact products on logic chip and super-capacitor are analyzed. The experimental results show that the plasma is the main reason for interfering with the operation of logic chips and super-capacitors. When the active material projectile impacts the simulated satellite at the speed of 1.26 km/s, 1.67 km/s and 2.13 km/s, the charge and discharge time of the super-capacitor increases by 3.28 times, 4.57 times and 6 times, respectively, and the maximum operating voltage performance decreases by 12.23%, 14.44% and 18.15%, respectively. When the impact velocities are 1.67 km/s and 2.13 km/s, the output signal of the CD74HC00 chip appears transient damage due to the injection of the plasma generated by the impact, which last 0.4 ms and 1.8 ms, respectively.

Multi-level representation for the control design of a super capacitor storage system for a microgrid connected application

In this paper an average multi-level representation of power electronic converters is used to design a dynamic model of a Super Capacitor Bank for a microgrid application. A dedicated multi-level modeling is designed to quantify energy variations in storage elements (super capacitors, DC bus) and various losses. We demonstrate that this model is sufficient to design the control system of the entire power storage system, meanwhile the super capacitors, the chopper and the grid connected converter. The proposed global model is simulated with the help of Matlab-SimulinkTM by considering two units of 48V 144F super capacitor modules.

Thermal profiling of ultracapacitor modules : A layered analysis

This study explores heat dissipation in supercapacitor modules tailored for energy-intensive applications. The research investigates the influence of different electrode material combinations on key performance parameters. Employing MATLAB and COMSOL simulations, the thermal conductivity of various layers within the supercapacitor module is analyzed. Findings reveal that polythene separators, responsible for encapsulating and segregating the module’s electrodes, represent critical points for controlled heat transfer. Significantly, the use of metal oxide in electrode construction contributes positively to regulated heat dissipation. Substituting polythene separators with synthesized materials is proposed to optimize heat dissipation. This research pioneers a data-driven analysis and software simulations to augment the study’s outcomes.

Peanut Oil Cake Biomass‐Derived Hierarchical Porous Carbon by Dual Step Activation as Potential Electrodes for Fabrication of Prototype Symmetric Supercapacitor Device

Peanut oil cake biomass is a major by‐product of oil industry and can be a suitable precursor for the production of biomass‐based porous carbon. Herein, dual‐stage activation, physical activation at 400°C, and chemical activation using KOH between 600 and 900°C are adopted to prepare hierarchical porous carbons (HPCs) from peanut oil cake biomass for use as electrode material in electrochemical supercapacitors. The textural and structural properties of the HPC were evaluated by N2‐adsorption/desorption, X‐ray diffraction, Raman, FT‐IR spectroscopy, and scanning electron microscopy. The prepared HPC inherited sufficient micropores and mesopores distribution with a maximum BET surface area of 640 m2/g. The electrochemical properties of the HPC electrodes were evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopic analysis. Among different HPC electrodes prepared, the carbon prepared at 800°C (HPC‐P8) electrode material exhibited a high specific capacitance of 187 F/g at 0.5 A/g in 1M Na2SO4 electrolyte in three‐electrode systems. Symmetric supercapacitors were also fabricated using HPC‐P8//HPC‐P8 as positive and negative electrodes using 1M Na2SO4 electrolyte, in a two‐electrode cell configuration via split cell method. Maximum specific capacitance of 30 F/g was achieved with superior cycle stability of 93.8% capacitance retention over 5,000 cycles for the symmetric device. The device operated at a wide potential window (0–2.0 V) resulted in appreciable specific energy and power density of 15.89 Wh/kg and 493 W/kg, respectively. HPC‐P8 had an ion diffusion coefficient of 7.79 × 10−8 cm2/s which is higher than the other prepared carbon samples. The symmetric device showed relatively high charge storage capacity and cyclic stability without any material degradation. The fabricated prototype portable supercapacitor module was tested for red LED glow with maximum intensity brightness up to 4 min. Thus, the present study reveals that HPC derived from peanut oil cake biomass can behave as a promising electrode material for supercapacitor applications.

Statistical analysis and Monte-Carlo simulation of printed supercapacitors for energy storage systems

This study presents a comprehensive statistical analysis of experimental parameters for 12 printed supercapacitors (SCs) using previously proposed equivalent circuit models (ECMs). Statistical distributions and descriptive statistics, including mean, P-value, and standard deviation (std), are reported indicating a normal distribution for various SC parameters. A statistical method is introduced to determine the maximum potential std in capacitance of multiple SCs within an energy storage module, ensuring voltage limits are not exceeded. A linear relationship is discovered between the applied voltage on the module comprising three SCs in series and the maximum potential std of capacitance, ensuring safe operation. Additionally, a statistical method predicts the energy window range of the SC module after operating an IC chip, enabling better decision-making and system management. Monte-Carlo (MC) simulations predict the long-term charge and discharge performance of individual SCs and the series-connected modules. Results indicate that as long as the parameters’ std remains below a defined threshold, charging behavior remains consistent. The MC simulations provide insight into voltage window ranges after 31 days of self-discharge, aiding in performance prediction and risk assessment. The statistical study approach empowers researchers in the field of printed SC energy storage, supporting performance evaluation, design validation, and evidence-based decision-making.

Residual energy extraction from near end-of-life lithium-ion batteries using a self-adaptive pulse discharge method

A modified self-adaptive pulse discharge (SAPD) method is adopted by this study to examine the feasibility of extracting residual energy from near end-of-life non-reusable lithium-ion batteries before disassembled. The SAPD model is used to determine the optimal frequency and duty cycle in the process of energy recovery, so the highest pulse discharge current can be obtained. A prototype including an improved active cell-balancing circuit, a modified SAPD control circuit, and a supercapacitor module switching circuit is developed to extract a battery bank that consists of at least one and at most 12 cells in parallel to reduce the discharge current as well as prevent damaged circuit components. The results of testing Sanyo UR14500P batteries show that the energy recovered from six to 12 cells ranges from 2630 to 2955 joules, and the corresponding recovery efficiency is from 64.97 to 66.19 %. Besides, with a randomly selected eight-cell pack, the SAPD method yields higher recovery efficiency than the short circuit discharge and pulse discharge methods, and the recovery efficiency increases by 11.74 % and 9.39 %, respectively. Although the results presented are far from being satisfactory from the perspective of efficiency, this study serves as a starting point for reusing and recycling resources.

Tuned morphology configuration to augment the electronic structure and durability of iron phosphide for efficient bifunctional electrocatalysis and charge storage

Although Fe-based materials have undergone morphological changes to alter their electrochemical activity in energy conversion and storage, an optimal strategy to achieve their ideal performance has yet to be discovered. Herein, a novel planar nanoflower and nanotubes-like morphology were established by the phosphorylation and sulfurization of iron hydroxide to obtain iron phosphide (FeP) and iron sulfide (FeS). Due to the presence of P-coordination with Fe-atoms, FeP material possessed improved electrical conductivity, catalytic property, and significantly specific capacitance among all synthesized samples. The potentiodynamic study was conducted in a 1 M basic solution where 216 and 218 mV of overpotentials were required to drag a current density of 10 mA/cm2 for OER and HER. In addition, the high turnover frequency, electrochemical surface area, and greater roughness factor contribute to making FeP the best candidate for H2 production; hence, it was employed for electrolyzer testing, which showed a lower potential of 1.68 V. Furthermore, FeP demonstrated improved electrochemical storage ability in supercapacitor module forms. The FeP clearly illustrated an outstanding specific capacitance of 2100 mF/cm2 and delivered 98 % stability, which is highly significant as it is not yet achieved by others. This work allows morphological tuning to improve electrocatalysis and charge storage in transition metal-based materials.

Multifunctional MOF-Derived Au, Co-Doped Porous Carbon Electrode for a Wearable Sweat Energy Harvesting-Storage Hybrid System.

As an efficient alternative for harnessing the energy from human's biofluid, a wearable energy harvesting-storage hybrid supercapacitor-biofuel cell (SC-BFC) microfluidic system is established with one multifunctional electrode. The electrode integrates metal-organic framework (MOF) derived carbon nanoarrays with embedded Au, Co nanoparticles on a flexible substrate, and is used for the symmetric supercapacitor as well as the enzyme nanocarriers of the biofuel cell. The electrochemical performance of the proposed electrode is evaluated, and the corresponding working mechanism is studied in depth according to the cyclic voltammetry and density functional theory calculation. The multiplexed microfluidic system is designed to pump and store natural sweat to maintain the continuous biofuel supply in the hybrid SC-BFC system. The biofuel cell module harvests electricity from lactate in sweat, and the symmetric supercapacitor module accommodates the bioelectricity for subsequent utilization. A numerical model is developed to validate the normal operation in poor and rich sweat under variable situations for the microfluidic system. One single SC-BFC unit can be self-charged to ≈0.8V with superior mechanical durability in on-body testing, as well as energy and power values of 7.2 mJ and 80.3 µW, respectively. It illustrates the promising scenery of energy harvesting-storage hybrid microfluidic system.

H–H Configuration of Modular EV Powertrain System Based on the Dual Three-Phase BLDC Motor and Battery-Supercapacitor Power Supply System

A modular approach to the construction of electric machines, drive systems, power supply systems is a new direction of modern technology development. Especially, the modular approach is promising for electric vehicles due to such positive aspects as increased efficiency, fault tolerance, overall reliability, safety, enhanced control capabilities, etc. In this work, the modular approach is comprehensively applied to an EV powertrain system, which includes a dual three-phase (DTP) BLDC motor with two machine modules of an asymmetric configuration, two battery modules and a supercapacitor module (SCM). The proposed H–H configuration of modular EV powertrain system includes four voltage source inverters that combine the power modules with the open ends of the windings (OEW) of the module machine armature, and provide control of their operation. Based on the developed mode system of the OEW machine module operation for EV traction and braking, a general control algorithm for the proposed configuration of the modular EV powertrain system has been developed. It combines the control of the operating modes with the functions of maintaining the required SOC level of the SCM and equalizing the SOCs of the two battery modules. The conducted simulation and experimental studies confirmed the workability and effectiveness of the proposed solutions.

Supercapacitor module quality prewarning based on the improved whale optimization algorithm and GM (1,1) gray prediction model

Supercapacitor module quality prewarning based on the improved whale optimization algorithm and GM (1,1) gray prediction model

An investigation into hybrid energy storage system control and power distribution for hybrid electric vehicles

This study aims to develop a hybrid energy storage system (HESS), targeting a commercialised Hybrid Electric Vehicle model (Hyundai Sonata), that consists of battery and supercapacitor cells, to evaluate its benefits on the battery's health and vehicle's performance. The different possible configurations of combining the two energy storage devices are discussed, while a semi-active configuration is considered for the purpose of simulation and testing, where the supercapacitor is connected to a bidirectional DC-DC converter, implemented with a newly developed control logic for the HESS. The analysis of the HESS is done by modelling the vehicle powertrain on the simulation software Ricardo IGNITE, while adapting the WLTC Class 2 drive cycle. The results are validated by comparing HESS model to the sole battery model, which showed the working status of the battery is stabilised by the addition of the supercapacitor in the HESS model during both the traction and regenerative modes. There is a significant reduction in the battery peak current, 15.26% and 20.54% for the charge and discharge current, respectively. Other improvements include a 0.43% increase on the average battery SOC, a 6.8% decrease in the battery's maximum temperature and 47.56% decrease in the average battery power. On the other hand, there was a 0.46% increase on vehicle's average L/100 km fuel consumption, due to losses in the supercapacitor system. Various other results are also compared in the discussion section, justifying the addition of the supercapacitor. The investigation finishes off by conducting a parametric study based on the number of supercapacitor modules in parallel, and comparing results such as current, power, fuel consumption and battery SOC. The results show that 2 supercapacitor modules provided the optimal results in terms of battery's current and power behaviour.

Adaptive Damping Control to Enhance Small-Signal Stability of DC Microgrids

This paper proposes an adaptive active control approach for damping the low-frequency oscillations in a DC microgrid (DC-MG). The DC-MG is comprised of hybrid power sources (HPSs) formed by a parallel set of supercapacitor modules and photovoltaic systems. The HPS controller includes a multi-loop voltage controller for adjusting the DC-MG voltage and a virtual impedance loop for damping current oscillations. The virtual impedance loop is augmented to the inner loop of the voltage controller. An adaptive tuning strategy is developed to adjust the damping coefficient of the virtual impedance loop optimally. In the tuning process, small-signal analysis is used to determine an initial adjustment for the damping coefficient. Subsequently, an approach based on intelligent neural network is intended to provide accurate online correction of the damping coefficient, which passes the dependency of the converter control system on the operating point conditions and accommodates different operation conditions. A sensitivity analysis is also conducted to investigate the effects of the system parameters on the HPS stability. Moreover, a mesh analysis is carried out to examine the stability of low-frequency modes of the whole DC-MG using the proposed control scheme. Case studies are conducted to demonstrate the performance of the proposed control strategy, and the analysis results are verified by Hardware-in-the-Loop (HIL) setup using OPAL-RT (OP5600) and dSPACE (DS1202) simulators.

Development of a MMC demonstrator for nuclear fusion devices power supplies

The modular multilevel converter (MMC) has become one of the most attractive converters for high-power applications such as high voltage DC (HVDC) converters, but also for fusion devices power supplies. The combination of this technology with a high power density energy storages such as supercapacitors (SC) represents a promising alternative to power the toroidal field (TF) magnets of the ASDEX (Axially Symmetric Divertor Experiment) Upgrade experiment operated at the Max-Planck-Institute for Plasma Physics (IPP) research center. After a first feasibility study, a single MMC submodule (SM) composed by four insulated-gate bipolar transistors (IGBT) forming a 4QC (4-quadrant chopper), a SC module and a power stage filter has been developed and successfully tested. Therefore, three additional identical modules were built to test their series and parallel operation in order to prove their capability to be scaled up.This work shows the step-by-step development of the MMC demonstrator, highlighting the results of the SM synchronized operation which is fundamental for the scalability of the system. The outcome of these experiments is relevant not only for the specific application of ASDEX Upgrade TF coils, but also for many other applications due to the flexible four-quadrant operation of the converter.

Full-Bridge Submodule Development of an MMC-Like Topology for ASDEX Upgrade Toroidal Field Coils Power Supply

The modular multilevel converter (MMC) has become one of the most attractive converters for high-power applications such as high-voltage dc (HVDC) converters, but also fusion devices’ power supplies. This converter, thanks to the discrete-leveled output voltage and its identical submodules (SMs) by which it is composed, represents a promising alternative to replace the flywheel generator (FG) that actually provides electrical power to Axially Symmetric Divertor Experiment (ASDEX) Upgrade device’s toroidal field (TF) coils. Due to the pulsed dc operation of these coils and their high-power needs (up to 150 MW) for each experiment, a small-scale version of MMC is under development with some differences compared with conventional ones: SM’s capacitors have been replaced with supercapacitor (SC) modules to increase the amount of available stored energy, while SMs belonging to different “rows” are interconnected to simplify their control and increase the reliability of the converter. This article shows the development and the operation of a single IGBT full-bridge (FB) SM highlighting advantages of this configuration and challenges of a full-scale converter: a proper power stage filter has been designed to protect SCs from voltage spikes and high-frequency current content generated during IGBT switching events, while SM’s control has been realized, thanks to the EtherCAT protocol, which ensures synchronization in case of SMs’ parallel operation and reliability of the future full-scale converter.

Design and Analysis of Sliding-Mode Artificial Neural Network Control Strategy for Hybrid PV-Battery-Supercapacitor System

Nowadays, the growing integration of renewable energy sources poses several challenges to electrical energy systems. The latter need be controlled by grid rules to ensure their stability and maintain the efficiency of renewable energy consumption. In this context, a novel HESS (hybrid energy storage system) control strategy, combining the PV (photovoltaic) generator with FLC (fuzzy logic control), SC (super-capacitor), and lithium-ion battery modules, is advanced. The proposed energy control rests on monitoring of the low-frequency and high-frequency electrical power components of the mismatch between power demand and generation, while applying the error component of the lithium-ion battery current. On accounting for the climatic condition and load variation considerations, the SC undertakes to momentarily absorb the high-frequency power component, while the low-frequency component is diverted to the lithium-ion battery. To improve the storage system’s performance, lifetime, and avoid load total disconnection during sudden variations, we consider equipping the envisioned energy control design with controllers of SM and ANN types. The MATLAB/Simulink based simulation results turn out to testify well the investigated HESS control scheme’s outstanding performance and efficiency in terms of DC bus voltage rapid regulation, thereby enhancing the battery’s lifetime and ensuring the PV system’s continuous flow.

Self-discharge estimation of supercapacitor modules at different ventilation levels

In most applications, a series connection of multiple supercapacitors is required to construct a module due to the low operating voltage of a single supercapacitor. Each supercapacitor in the module has a different temperature value because of inconsistent temperature distribution and different heat exchange rates. On the other hand, temperature affects the self-discharge process of a supercapacitor. Hence, the difference in the temperatures of supercapacitors leads to different self-discharge characteristics. In this study, the effect of temperature distribution on the self-discharge of a supercapacitor module consisting of eight electric double-layer capacitors (EDLC) is investigated. For this purpose, a lumped thermal model (LTM) is considered for the EDLC module. The parameters of the LTM are extracted from the experimental data. The measured (observed) core temperature of each EDLC cell from the LTM is substituted in the TAFEL equation and the self-discharge behavior of each cell is achieved according to its temperature. The total self-discharge of the EDLC module is obtained from the summation of all self-discharge voltage trajectories in the cells. In order to show the effectiveness of the proposed approach for analyzing the self-discharge phenomenon in the EDLC module, three different possible ventilation levels are considered.