The Design Optimization of Si-Based Isotope Microbattery

2015 ◽  
Vol 742 ◽  
pp. 748-752
Author(s):  
Zai Jun Cheng ◽  
Chuan Wen Huang ◽  
Peng Zhou
Keyword(s):  
Theoretical Model ◽  
Power Density ◽  
Output Power ◽  
Doping Concentration ◽  
Maximum Output Power ◽  
Maximum Output ◽  
Optimal Doping ◽  
Output Performance ◽  
Optimal Doping Concentration ◽  
Electrical Output

A theoretical model of Si-based P-N junction isotope microbattery’s electrical output was demonstrated. According to the model, electrical output performance of a 1*1 mm2Si-based isotope microbattery under the irradiation of a 1 mCi63Ni source was simulated. The optimal doping concentration was obtained when the microbattery had the maximum output power density of 0.95 nW/cm2.

scholarly journals Finite Time Thermodynamic Optimization of an Irreversible Proton Exchange Membrane Fuel Cell for Vehicle Use

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 419 ◽  
Author(s):  
Changjie Li ◽  
Ye Liu ◽  
Bing Xu ◽  
Zheshu Ma
Keyword(s):  
Power Density ◽  
Output Power ◽  
Proton Exchange Membrane ◽  
Operating Temperature ◽  
Maximum Output Power ◽  
Proton Exchange ◽  
Maximum Output ◽  
Operating Pressure ◽  
Output Efficiency ◽  
Exchange Membrane

A finite time thermodynamic model of an irreversible proton exchange membrane fuel cell (PEMFC) for vehicle use was established considering the effects of polarization losses and leakage current. Effects of operating parameters, including operating temperature, operating pressure, proton exchange membrane water content, and proton exchange membrane thickness, on the optimal performance of the irreversible PEMFC are numerically studied in detail. When the operating temperature of the PEMFC increases, the optimal performances of PEMFC including output power density, output efficiency, ecological objective function, and ecological coefficient of performance, will be improved. Among them, the optimal ecological objective function increased by 81%. The proton film thickness has little effect on the output efficiency and the ecological of coefficient performance. The maximum output power density increased by 58% as the water content of the proton exchange membrane increased from 50% to the saturation point. The maximum output power density increases with the operating pressure.

4H-SiC Planar MESFETs on High-Purity Semi-Insulating Substrates

2007 ◽  
Vol 556-557 ◽  
pp. 763-766 ◽  
Author(s):  
Jeong Hyuk Yim ◽  
Ho Keun Song ◽  
Jeong Hyun Moon ◽  
Han Seok Seo ◽  
Jong Ho Lee ◽  
...  
Keyword(s):  
Power Density ◽  
Output Power ◽  
High Purity ◽  
Maximum Output Power ◽  
Drain Current ◽  
Maximum Output ◽  
Power Gain ◽  
Si Substrates ◽  
Class A ◽  
Current Instability

Planar MESFETs were fabricated on high-purity semi-insulating (HPSI) 4H-SiC substrates. The saturation drain current of the fabricated MESFETs with a gate length of 0.5 μm and a gate width of 100 μm was 430 mA/mm, and the transconductance was 25 mS/mm. The maximum oscillation frequency and cut-off frequency were 26.4 GHz and 7.2 GHz, respectively. The power gain was 8.4 dB and the maximum output power density was 2.8 W/mm for operation of class A at CW 2 GHz. MESFETs on HPSI substrates showed no current instability and much higher output power density in comparison to MESFETs on vanadium-doped SI substrates.

Influence of electrical impedance and mechanical bistability on Galfenol-based unimorph harvesters

2016 ◽  
Vol 28 (3) ◽  
pp. 421-431 ◽  
Author(s):  
Zhangxian Deng ◽  
Marcelo J Dapino
Keyword(s):  
Power Density ◽  
Output Power ◽  
Maximum Output Power ◽  
Element Model ◽  
Maximum Energy ◽  
Bistable System ◽  
Maximum Output ◽  
Base Excitation ◽  
Frequency Bandwidth ◽  
Electrical Loads

A study on iron-gallium (Galfenol) unimorph harvesters is presented which is focused on extending the power density and frequency bandwidth of these devices. A thickness ratio of 2 (ratio of substrate to Galfenol thickness) has been shown to achieve maximum power density under base excitation, but the effect of electrical load capacitance on performance has not been investigated. This article experimentally analyzes the influence of capacitive electrical loads and extends the excitation type to tip impulse. For resistive-capacitive electrical loads, the maximum energy conversion efficiency achieved under impulsive excitation is 5.93%, while the maximum output power and output power density observed for a 139.5 Hz, 3 [Formula: see text] amplitude sinusoidal base excitation is 0.45 W and 6.88 [Formula: see text], respectively, which are 8% higher than those measured under purely resistive loads. A finite element model for Galfenol unimorph harvesters, which incorporates magnetic, mechanical, and electrical dynamics, is developed and validated using impulsive responses. A buckled unimorph beam is experimentally investigated. The proposed bistable system is shown to extend the harvester’s frequency bandwidth.

Development of High Performance Micro DMFCS and a DMFC Stack

2005 ◽  
Vol 3 (2) ◽  
pp. 131-136 ◽  
Author(s):  
G. Q. Lu ◽  
C. Y. Wang
Keyword(s):  
Power Density ◽  
Silicon Wafer ◽  
Output Power ◽  
Oxygen Transport ◽  
Maximum Output Power ◽  
Maximum Power ◽  
Membrane Electrode ◽  
Maximum Output ◽  
Maximum Power Density ◽  
Air Breathing

A silicon-based micro direct methanol fuel cell (μDMFC) for portable applications has been fabricated and its electrochemical characterization carried out. A membrane-electrode assembly (MEA) was specially fabricated to mitigate methanol crossover. The cell with active area of 1.625cm2 demonstrated a maximum power density of 50mW∕cm2 at 60°C. Since the silicon wafer is too fragile to compress for sealing, and a thicker layer of gold has to be coated on the silicon wafer to reduce contact resistance, further development of micro DMFCs for high power application was carried out using stainless steel as bipolar plate in which flow channels were fabricated by photochemical etching technology. The maximum power density of the micro DMFC reaches 62.5mW∕cm2 at 40°C and 100mW∕cm2 at 60°C with atmospheric pressure. An 8-cell air-breathing DMFC stack has been developed. Mass transport phenomena such as water transport and oxygen transport were investigated. By using a water management technique, cathode flooding was avoided in our air-breathing DMFC stack. Furthermore, it was found that oxygen transport in the air-breathing cathode is still very efficient. The DMFC stack produced a maximum output power of 1.33W at 2.21V at room temperature, corresponding to a power density of 33.3mW∕cm2. A passive DMFC using pure methanol was demonstrated with steady-state output power of 20-25mW∕cm2 over more than 10h without heat management.

scholarly journals Design Optimization and Comparison of Cylindrical Electromagnetic Vibration Energy Harvesters

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7985
Author(s):  
Tra Nguyen Phan ◽  
Jesus Javier Aranda ◽  
Bengt Oelmann ◽  
Sebastian Bader
Keyword(s):  
Power Density ◽  
Output Power ◽  
Electromagnetic Coupling ◽  
Maximum Output Power ◽  
Optimization Procedure ◽  
Vibration Energy ◽  
Maximum Output ◽  
Energy Harvesters ◽  
Electromagnetic Vibration ◽  
Halbach Array

Investigating the coil–magnet structure plays a significant role in the design process of the electromagnetic energy harvester due to the effect on the harvester’s performance. In this paper, the performance of four different electromagnetic vibration energy harvesters with cylindrical shapes constrained in the same volume were under investigation. The utilized structures are (i) two opposite polarized magnets spaced by a mild steel; (ii) a Halbach array with three magnets and one coil; (iii) a Halbach array with five magnets and one coil; and (iv) a Halbach array with five magnets and three coils. We utilized a completely automatic optimization procedure with the help of an optimization algorithm implemented in Python, supported by simulations in ANSYS Maxwell and MATLAB Simulink to obtain the maximum output power for each configuration. The simulation results show that the Halbach array with three magnets and one coil is the best for configurations with the Halbach array. Additionally, among all configurations, the harvester with two opposing magnets provides the highest output power and volume power density, while the Halbach array with three magnets and one coil provides the highest mass power density. The paper also demonstrates limitations of using the electromagnetic coupling coefficient as a metric for harvester optimization, if the ultimate goal is maximization of output power.

scholarly journals Numerical analysis of semiconductor thermoelectric generator

2020 ◽  
Vol 24 (3 Part A) ◽  
pp. 1585-1591
Author(s):  
Zhifei Wu ◽  
Yuxia Xiang ◽  
Jianjun Wang
Keyword(s):  
Contact Resistance ◽  
Output Power ◽  
Temperature Difference ◽  
Output Voltage ◽  
Thermoelectric Generator ◽  
Maximum Output Power ◽  
Load Resistance ◽  
Maximum Output ◽  
Generation Model ◽  
Output Performance

A thermoelectric generation model is proposed based on the structure of thermoelectric generator, working conditions, the effect of air heat transfer and contact resistance in thermoelectric components. In addition, the effect of the thermoelectric generator output performance under the condition of different temperature of the cold and heat source, contact resistance between the cold-end and hot-end, the load resistance and the contact resistance is calculated. The results show that the output voltage is linear associate with the temperature difference between hot and cold ends, however, the output power increase along with the increase of temperature of hot-end and decrease of cold-end. The output voltage reaches 5.76 V and the output power reaches 9.81 W when the temperature difference is 200?C. Assume that the contact resistance is ignored, the output voltage and power reach peak values of 3.61 V and 3.85 W. The output performance of thermoelectric generator decreases with the increase of thermal contact resistance at hot and cold ends, and the reduction is getting lower and lower. With the increase of the load resistance, the output power increases at the beginning and then decreases. The optimal output power is 3.69 W when the contact resistance is 0 ? and the optimal load resistance is 3.3 ?. The maximum output power corresponding to neglecting the contact resistance will be reduced by 13.5% when the contact resistance is 0.5 ?.

Development of High Performance Micro DMFCs and a DMFC Stack

2005 ◽  
Author(s):  
Guoqiang Lu ◽  
Chao-Yang Wang
Keyword(s):  
Power Density ◽  
Silicon Wafer ◽  
Output Power ◽  
Oxygen Transport ◽  
Maximum Output Power ◽  
Maximum Power ◽  
Membrane Electrode ◽  
Maximum Output ◽  
Maximum Power Density ◽  
Air Breathing

A silicon-based micro direct methanol fuel cell (μDMFC) for portable applications has been fabricated and its electrochemical characterization carried out. A membrane-electrode assembly (MEA) was specially fabricated to mitigate methanol crossover. The cell with the active area of 1.625 cm2 demonstrated a maximum power density of 50 mW/cm2 at 60°C. Since silicon wafer is too fragile to compress for sealing, and a thicker layer of gold has to be coated on the silicon wafer to reduce contact resistance, further development of micro DMFCs for high power application was carried out using stainless steel plate as bipolar plate in which flow channels were fabricated by photochemical etching technology. The maximum power density of the micro DMFC reaches 62.5 mW/cm2 at 40 °C and 100 mW/cm2 at 60°C with atmospheric pressure. An 8-cell air-breathing DMFC stack has been developed. Mass transport phenomena such as water transport, and oxygen transport were investigated. By using a water management technique, cathode flooding was avoided in our air-breathing DMFC stack. Furthermore, it was found that oxygen transport in the air-breathing cathode is still very efficient. The DMFC stack produced a maximum output power of 1.33 W at 2.21 V at room temperature, corresponding to a power density of 33.3 mW/cm2. A passive DMFC using pure methanol was demonstrated with steady-state output power of 20–25 mW/cm2 over more than 10 hours without heat management.

Linear and rotational microhydraulic actuators driven by electrowetting

2018 ◽  
Vol 3 (22) ◽  
pp. eaat5643 ◽  
Author(s):  
Jakub Kedzierski ◽  
Eric Holihan
Keyword(s):  
Surface Tension ◽  
Power Density ◽  
Output Power ◽  
Electrical Power ◽  
Maximum Output Power ◽  
Surface Tension Force ◽  
Maximum Output ◽  
Electric Motors ◽  
Torque Density ◽  
Output Force

Microhydraulic actuators offer a new way to convert electrical power to mechanical power on a microscale with an unmatched combination of power density and efficiency. Actuators work by combining surface tension force contributions from a large number of droplets distorted by electrowetting electrodes. This paper reports on the behavior of microgram-scale linear and rotational microhydraulic actuators with output force/weight ratios of 5500, cycle frequencies of 4 kilohertz, <1-micrometer movement precision, and accelerations of 3 kilometers/second2. The power density and the efficiency of the actuators were characterized by simultaneously measuring the mechanical work performed and the electrical power applied. Maximum output power density was 0.93 kilowatt/kilogram, comparable with the best electric motors. At maximum power, the actuator was 60% efficient, but efficiencies were as high as 83% at lower power. Rotational actuators demonstrated a torque density of 79 newton meters/kilogram, substantially more than electric motors of comparable diameter. Scaling the droplet pitch from 100 to 48 micrometers increased power density from 0.27 to 0.93 kilowatt/kilogram, validating the quadratic scaling of actuator power.

scholarly journals One-Step Preparation of Biochar Electrodes and Their Applications in Sediment Microbial Electrochemical Systems

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 508
Author(s):  
Kui You ◽  
Zihan Zhou ◽  
Chao Gao ◽  
Qiao Yang
Keyword(s):  
Output Power ◽  
Electrode Materials ◽  
Maximum Output Power ◽  
Composite Cathode ◽  
Maximum Output ◽  
Electrochemical Systems ◽  
Composite Cathodes ◽  
One Step ◽  
Microbial Electrochemical Systems ◽  
Hot Melt

Biochar is a kind of carbon-rich material formed by pyrolysis of biomass at high temperature in the absence or limitation of oxygen. It has abundant pore structure and a large surface area, which could be considered the beneficial characteristics for electrodes of microbial electrochemical systems. In this study, reed was used as the raw material of biochar and six biochar-based electrode materials were obtained by three methods, including one-step biochar cathodes (BC 800 and BC 700), biochar/polyethylene composite cathodes (BP 5:5 and BP 6:4), and biochar/polyaniline/hot-melt adhesive composite cathode (BPP 5:1:4 and BPP 4:1:5). The basic physical properties and electrochemical properties of the self-made biochar electrode materials were characterized. Selected biochar-based electrode materials were used as the cathode of sediment microbial electrochemical reactors. The reactor with pure biochar electrode (BC 800) achieves a maximum output power density of 9.15 ± 0.02 mW/m2, which increases the output power by nearly 80% compared with carbon felt. When using a biochar/polyaniline/hot-melt adhesive (BPP 5:1:4) composite cathode, the output power was increased by 2.33 times. Under the premise of ensuring the molding of the material, the higher the content of biochar, the better the electrochemical performance of the electrodes. The treatment of reed powder before pyrolysis is an important factor for the molding of biochar. The one-step molding biochar cathode had satisfactory performance in sediment microbial electrochemical systems. By exploring the biochar-based electrode, waste biomass could be reused, which is beneficial for the environment.

scholarly journals Study of the Properties of a Hybrid Piezoelectric and Electromagnetic Energy Harvester for a Civil Engineering Low-Frequency Sloshing Environment

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 391
Author(s):  
Nan Wu ◽  
Yuncheng He ◽  
Jiyang Fu ◽  
Peng Liao
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Civil Engineering ◽  
Maximum Output Power ◽  
Low Frequency ◽  
Electromagnetic Energy ◽  
Maximum Output ◽  
Piezoelectric Film ◽  
Hybrid Energy ◽  
Level Height

In this paper a novel hybrid piezoelectric and electromagnetic energy harvester for civil engineering low-frequency sloshing environment is reported. The architecture, fabrication and characterization of the harvester are discussed. The hybrid energy harvester is composed of a permanent magnet, copper coil, and PVDF(polyvinylidene difluoride) piezoelectric film, and the upper U-tube device containing a cylindrical fluid barrier is connected to the foundation support plate by a hinge and spring. The two primary means of energy collection were through the vortex street, which alternately impacted the PVDF piezoelectric film through fluid shedding, and the electromotive force (EMF) induced by changes in the magnetic field position in the conducting coil. Experimentally, the maximum output power of the piezoelectric transformer of the hybrid energy harvester was 2.47 μW (circuit load 270 kΩ; liquid level height 80 mm); and the maximum output power of the electromagnetic generator was 2.72 μW (circuit load 470 kΩ; liquid level height 60 mm). The low-frequency sloshing energy collected by this energy harvester can drive microsensors for civil engineering monitoring.

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