Energy Harvesting & Storage Tech Digest - January 2017

Push for power

Researchers at Michigan State University have a developed a ferroelectret nanogenerator (FENG) that can harvest energy from human motion. It is a silicon wafer fabricated with layers of silver, polyimide and polypropylene ferroelectret (PPFE). Voids in the PPFE film keep positive and negative charges separate within the structure, and this enables the creation of electrical energy from compression by either human force or other mechanical energy. The piezoelectric coefficient of PPFE films is significantly higher than conventional piezoelectric devices. The scientists demonstrated FENG powering an LCD touchscreen, a bank of 20 LED lights and a flexible keyboard, all powered by a press of a hand. When folded, a FENG will not only continue to create electric current but will produce a higher current, according to the researchers. They plan to experiment with the potential to power a headset by placing a FENG in the heels of shoes. 

Good vibrations: using low frequency vibrations as power source

Energy from touch could be harvested to power electrical devices according to a Samsung-funded study conducted by Penn State University scientists. Currently there is a powering method which harvests ambient mechanical energy; however, according to the Penn-State team this requires a vibration rate of more than ten vibrations per second to be effective enough to power a smartphone for example. Penn State has developed an organic polymer p-n junction which is capable of converting low frequency vibrations into electricity. This means that a device could be powered by human touch or any other form of motion, eg walking, or waves. The researchers believe that incorporating this tech into smartphones could deliver 40% of the required power. 

Riding the energy wave: wave farms

Harnessing the latent energy potential of waves is an area Columbia Power Technologies is investigating with its StingRAY wave energy converter. The US Energy Department’s National Renewable Energy Laboratory (NREL) is carrying out tests on StingRAY in its wind technology testing centre with a view to open water testing later in 2017 at the US Navy’s Wave Energy Testing Site in Hawaii. 
The StingRAY converts wave energy from the forward and aft floats that are attached to two rotary electric generators. The generated electricity is then conditioned to be suitable for national-grid consumption before being sent to an offshore substation for transmission to shore. 

Sunny power source for sensors

Sol Chip’s Sol Chip Comm (SCC) is an autonomous, wireless tag that utilises Sol Chip’s solar battery (called LightBattery), designed for use in agriculture and smart irrigation. The SCC transmits real-time data from sensors detecting soil moisture, soil temperature, ambient temperature, air temperature, and nutrient levels to a server that then analyses the data, offering recommendations on adjustments. The device is solar powered and Sol Chip says it can operate continuously for more than ten years without maintenance. 

UK trains could be powered by solar panels

Imperial College London and 10:10, a company focused on implementation of renewable energy sources, have announced their project to investigate the use of trackside solar panels to power trains. They plan to connect solar panels which will bypass the electricity grid directly to the train line. This, they say, will enable the provision of power exactly when needed i.e. during peak times. The project is looking at the feasibility of providing the power through the third rail, which supplies electricity at 750V DC to trains in some parts of the UK, from a powerline close to the ground. Some issues are: 1) the third rail is sometimes used for signalling, therefore the solar power could disrupt the signal; 2) safety of the power source integration: managing how and when to use solar power in the third rail. The project will begin in February 2017.

Fire resistant Li-ion battery technology

Stanford University researchers have developed a way to prevent fires in lithium ion batteries by adding pouches of heat activated triphenyl phosphate (TPP) into the battery’s electrolyte fluid. Li-ion batteries can catch light through charging too fast or an error during manufacture that can cause a short circuit. The scientist’s solution is to place parcels of TTP into the Li-ion fluid when the fluid reaches a temperature of 150C, the shell of the parcel melts releasing the chemical compound. The potential or actual battery fire has been shown to be extinguished in 0.4 seconds.

Moxia trials smart battery for solar power network

Energy storage company Moixa in collaboration with Northern Powergrid, will be rolling out a GBP250,00 trial to see if it can make solar power more valuable for homeowners and less of a problem for the national grid. In Oxspring, Barnsley, UK, 40 Moxia Smart Batteries will be installed in homes, 30 of which currently have solar panels and 10 which don’t. The aim is to demonstrate the effectiveness of using smart batteries that allow the home owner to store harvested solar energy for use at a later time in the home or else to sell to the grid outside of peak solar power production (noon) when the grid is overloaded with an overabundance of solar energy. The solar electricity collectors could also sell spare electricity to those without solar panels, for storage and later use in their own batteries.   

Samsung EV battery promises faster charging, less weight, and longer distances

Samsung SDI has displayed its latest electric battery designed for electric vehicles. The company says that this lithium ion battery is able to travel for 600km on a single charge. It has an ‘integrated battery module’ design (it has more than 24 cells with capacities of 6-8kWh compared to a conventional electric battery which has 12 cells and a capacity of 2-3kWh) that the company claims means a 10% decrease in component units and weight compared to current batteries. Samsung SDI reports that due to fast charging technology the battery is able to charge up to 80% of capacity in only 20 minutes. It aims for mass production in 2021. 

Polypyrrole and perovskite catalyst for fuel cells could reduce cost

Ulsan National Institute of Science and Technology(UNIST) researchers have recently revealed a way to increase efficiency of metal-air batteries by using a conducting polymer. Metal air batteries (fuel cells) rely on the conversion of oxygen to metal oxide or water at the cathode. This requires catalysts such as platinum which are expensive. The scientists have reported that a similar effect can be obtained through the use of perovskite in conjunction with polypyrrole. Once used together the catalytic effect can match that of platinum.

Chilly temperature required for perovskite solar cell

At team of researchers at the University of Gottingen have developed a solid state solar cell made from the mineral perovskite. The mechanism behind the cell is polaron excitation, which combines the excitation of electrons (using photons) and vibrations in the crystal structure of the perovskite, to generate electrical energy. This is a different method of converting solar energy into electrical energy to that used in traditional solar cells, in which vibrations lead to a significant loss of power. However, the temperature required – minus 35 degrees Celsius – currently precludes this method from immediate widespread, practical application. The researchers are attempting to increase the working temperature of the material. 


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