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Introduction to Flexible Batteries
Published in Ye Zhang, Lie Wang, Yang Zhao, Huisheng Peng, Flexible Batteries, 2022
Ye Zhang, Lie Wang, Yang Zhao, Huisheng Peng
The performance evaluation of flexible batteries can be divided into two categories: electrochemical property and flexibility. Electrochemical property generally follows the paradigm of conventional batteries, including charge/discharge curves, cycle longevity, battery capacities, rate capability, temperature characteristics, and power/energy densities. Charge/discharge curves signify the battery characteristics, including charge/discharge voltage plateaus, specific capacities, and operation stability represented from the continuity of the curves. Cycle life indicates the times a battery can be used under normal conditions, expressed in cycle numbers. Battery capacity refers to the overall charge stored in a charge/discharge cycle, expressed in mAh or Ah unit. For convenience in comparison, the battery capacity is usually normalized to gravimetric or volumetric specific capacities, which can be calculated by the following equations: Cgravimetric=∫idtmCvolumetric=∫idtV
Energy Storage
Published in Denise Wilson, Wearable Solar Cell Systems, 2019
One of the more common indicators of the goodness of a battery, whether rechargeable or single-use, is its capacity, which is typically provided in ampere-hours (Ah) or milliampere-hours (mAh). Unfortunately, there are a number of drawbacks to using capacity to identify battery quality. First, capacity in Ah or mAh speaks to the amount of current that can be delivered over a certain period of time. Ideally, a 20-mAh battery would deliver 20 mA for 1 hour or 10 mA for 2 hours. But neither scenario speaks to the true energy capacity of the battery. For this, the capacity must be multiplied by the nominal voltage of the battery. The nominal voltage, in turn, is dependent on the battery material and technology. For example, a NiCd battery has a nominal cell voltage of 1.2 V. With a capacity of 10 mAh, the battery can deliver 0.012 Wh. In contrast, a Li-ion battery with a cell voltage of 3.6 V and the same capacity, can deliver three times that amount or 0.036 Wh. Furthermore, capacity typically degrades with increasing current demand and does so differently depending on the type and size of the battery as well as environmental factors including temperature. For portables and wearables, these issues are typically addressed during the design of electronic devices and not during the design of charging systems, whether these charging systems are based on AC, DC, solar, or some other energy source.
Connected Devices
Published in Saad Z. Asif, 5G Mobile Communications Concepts and Technologies, 2018
The capacity is how much charge a battery can hold, often measured in units of mAh (milli-amp-hour). It is determined by the hours of service of 1 volt times the discharge rate. In general, batteries with larger mAh ratings will last longer than those with smaller ratings, assuming that the two are subjected to the same patterns of usage.
Science of 2.5 dimensional materials: paradigm shift of materials science toward future social innovation
Published in Science and Technology of Advanced Materials, 2022
Hiroki Ago, Susumu Okada, Yasumitsu Miyata, Kazunari Matsuda, Mikito Koshino, Kosei Ueno, Kosuke Nagashio
In a further example, BLG can be used to create a promising electrode material with high conductivity and transparency, by intercalating molecules and ions between the graphene layers. As already shown in Figure 5(d), intercalating MoCl5 molecules into twist-rich BLG significantly reduced the sheet resistance (83 Ω Ω−1), allowing to apply it to organic solar cells with a high PCE [79]. Graphene-like graphite (GLG, Figure 11(c), which has a 2D stacked, porous graphitic structure with chemically introduced C-O-C units, was applied as the anode in a Li-ion battery. The GLG electrode showed a large capacity of 608 mAh/g at the upper cell voltage limit of 2 V [181]. In contrast, MoS2 and MoSe2 nanosheets were applied as cathodes with Mg plate anodes for hybrid Mg-Li ion batteries [182]. The stacked structure of carbon-stabilized heat-expanded TMDC is expected to find applications in both the anode and cathode of carbon-free Li-ion batteries. Furthermore, MoS2 thin films are attracting interest as photoelectrodes for hydrogen evolution through water reduction because of their high light absorbance and high electrochemical activity [183].
Water-energy nexus management strategy towards sustainable mobility goal in smart cities
Published in Urban Water Journal, 2021
Helena M. Ramos, Lluis Giralt, P. Amparo López-Jiménez, Modesto Pérez-Sánchez
This case study consists of the creation and development of an energy recovery hydraulic power plant capable of fulfilling the energy necessities of two electrical bike stations of Gira, Lisbon town. Gira Bicicletas de Lisboa is a public service offered by EMEL company since September 2017. The users can move around the city with their bikes during their operational schedule of 20 hours per day, from 6:00 am to 2:00 am. The charging stations feed the bikes with a tension of 42 ± 0.1 V and an electric current of 6250 mAh. The batteries have a nominal tension of 37 V and a nominal capacity of 12,800 mAh. It was decided that the power energy plant designed would try to fulfil the necessities of the two stations, called 307 and 308 respectively, and they are near the park charging. These stations are located at Marquês de Pombal in Lisbon (Portugal). The energy study concluded these two stations had an estimated energy consumption equal to 31.2 kWh/day. Figure 2a shows the hourly demanded power. It can be observed that the maximum power that the charging station has to provide is around 3500 W. Figure 2 shows there are hours, in which there is no activity on Gira’s bikes, particularly from 2:00 to 6:00, there is no need for supplying energy to any bike. As the public gardens are irrigated during the nighttime, the recoverable energy will take place during the night and the consumption during the rest of the day. This situation establishes the need to propose a new irrigation schedule to closer the electrical need and the possibility to use hydraulic recovery systems.
EJBot-II: an optimized skid-steering propeller-type climbing robot with transition mechanism
Published in Advanced Robotics, 2019
Mohamed G. Alkalla, Mohamed A. Fanni, Abdel− Fattah Mohamed, Shuji Hashimoto, Hideyuki Sawada, Takanobu Miwa, Amr Hamed
In this section, EJBot-II prototype is fabricated and assembled. It consists of four main systems. The first one is the thruster unit which includes two propellers, brushless motors, and electronic speed controller (ESC). The second system is the driving and steering system which consists of two tracks, DC geared motors, and one DC dual motor driver (Roboclaw 2×7A). The third system is the transition mechanism which includes two servo motors and arms. The fourth system is the controller unit which is mainly based on a tele-operated radio control system consisting of 9-channel 2.4-GHz hoTT receiver and transmitter. The main robot components are shown in Figure 22. EJBot-II is supplied with power by a portable LIPO battery that has 6-cell and 3000 milli-Ampere-hour (mAh) capacity. Its mass is around 300 g and mounted directly on the robot platform for navigating any structure easily, especially the complex environment with a lot of obstacles. The battery provides the robot with a power enough to operate about 10–15 minutes. In case of using a battery with larger capacity, it is preferred to use a connecting cable, where a battery of 6-cell and 5000 mAh has a weight of 750 g. Consequently, this weight will reduce the robot payload capacity greatly. This high capacity battery can operate the robot around 45 minutes. So, it has a merit of long operation time and durability, even it has some cable issues.