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February 05, 2010

Car Bodywork Could Double as Battery and T-Shirts Could Become Batteries

1. Imperial College of London- Parts of a car’s bodywork could one day double up as its battery, according to the scientists behind a new €3.4 million project announced today.

Researchers from Imperial College London and their European partners, including Volvo Car Corporation, are developing a prototype material which can store and discharge electrical energy and which is also strong and lightweight enough to be used for car parts.

The researchers believe the material, which has been patented by Imperial, could potentially be used for the casings of many everyday objects such as mobile phones and computers, so that they would not need a separate battery. This would make such devices smaller, more lightweight and more portable.

In the new project, the scientists are planning to develop the composite material so that it can be used to replace the metal flooring in the car boot, called the wheel well, which holds the spare wheel. Volvo is investigating the possibility of fitting this wheel well component into prototype cars for testing purposes.

The team says replacing a metal wheel well with a composite one could enable Volvo to reduce the number of batteries needed to power the electric motor. They believe this could lead to a 15 per cent reduction in the car’s overall weight, which should significantly improve the range of future hybrid cars.

The researchers say that the composite material that they are developing, which is made of carbon fibres and a polymer resin, will store and discharge large amounts of energy much more quickly than conventional batteries. In addition, the material does not use chemical processes, making it quicker to recharge than conventional batteries. Furthermore, this recharging process causes little degradation in the composite material, because it does not involve a chemical reaction, whereas conventional batteries degrade over time.



2. Stanford researchers have moved from making batteries from paper to making batteries from cloth. Your-T-shirt could become a lighted, moving display The material will enable a t-shirt battery to hold three times more power than a regular cellphone battery.

A team of Stanford researchers is producing batteries and simple capacitors from ordinary textiles dipped in nanoparticle-infused ink. The conductive textiles – dubbed "eTextiles" – represent a new class of integrated energy storage device, born from the synthesis of prehistoric technology with cutting-edge materials science.

"We have been developing all kinds of materials, trying to revolutionize battery performance," said Yi Cui, assistant professor of materials science and engineering at Stanford. "Recently, we started to think about how to make batteries in a very different way from before."

While conventional batteries are made by coating metallic foil in a particle slurry and rolling it into compact form – a capital-intensive process – the new energy textiles were manufactured using a simple "dipping and drying" procedure, whereby a strip of fabric is coated with a special ink formula and dehydrated in the oven.

The procedure works for manufacturing batteries or supercapacitors, depending on the contents of the ink – oxide particles such as LiCoO2 for batteries; conductive carbon molecules (single-walled carbon nanotubes, or SWNTs) for supercapacitors. Up to now, the team has only used black ink, but Cui said it is possible to produce a range of colors by adding different dyes to the carbon nanotubes.

Cui's team had previously developed paper batteries and supercapacitors using a similar process, but the new energy textiles exhibited some clear advantages over their paper predecessors. With a reported energy density of 20 Watt-hours per kilogram, a piece of eTextile weighing 0.3 0.030 [correction made here -error was in original press release] kilograms (about an ounce, the approximate weight of a T-shirt) could hold up to three times more energy than a cell phone battery

Stretchable, Porous, and Conductive Energy Textiles

Recently there is strong interest in lightweight, flexible, and wearable electronics to meet the technological demands of modern society. Integrated energy storage devices of this type are a key area that is still significantly underdeveloped. Here, we describe wearable power devices using everyday textiles as the platform. With an extremely simple “dipping and drying” process using single-walled carbon nanotube (SWNT) ink, we produced highly conductive textiles with conductivity of 125 S cm−1 and sheet resistance less than 1 Ω/sq. Such conductive textiles show outstanding flexibility and stretchability and demonstrate strong adhesion between the SWNTs and the textiles of interest. Supercapacitors made from these conductive textiles show high areal capacitance, up to 0.48F/cm2, and high specific energy. We demonstrate the loading of pseudocapacitor materials into these conductive textiles that leads to a 24-fold increase of the areal capacitance of the device. These highly conductive textiles can provide new design opportunities for wearable electronics and energy storage applications.



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