What if you might “stick” your power source where you need it? This is the challenge taken up by scientists from the Massachusetts Institute of Technology (MIT). They made flexible solar panels, which they glued to fabric.
These solar cells can be attached to a large number of surfaces, turning them into a source of energy with little effort, the scientists explain. They published an article in Small Methods to report on their progress. Thinner than a human hair, their device was glued to a light and resistant fabric. It is thus very adaptable, and can serve as a mobile energy source or be deployed in remote locations, for example during emergency interventions.
In a press release on the subjectMIT says it already sees many uses for the technology: They might, for example, be incorporated into the sails of a boat to provide power at sea, stuck to tents and tarpaulins deployed during disaster relief operations, or applied to the fenders of drones to extend their range “, specifies the Institute. As this solar “fabric” requires little infrastructure to be installed, it would also be suitable for a built environment, in which it might be integrated without being too bulky.
« A typical rooftop solar installation in Massachusetts is around 8000 watts. To generate the same amount of energy, our fabric photovoltaic panels would only add regarding 20 kilograms to the roof of a house. “says Mayuran Saravanapavanantham, co-author of the article. In other words, their cells weigh a hundredth of the weight of conventional solar panels, and generate 18 times more energy per kilogram.
For scientists, it is this integrability that is the real strength of their technology. “ The parameters used to evaluate new solar cell technology are usually limited to their power conversion efficiency and dollar cost per watt. Integrability – the ease with which new technology can be adapted – is equally important. Lightweight solar fabrics allow this integrability, which has given impetus to current work. We are working to accelerate the adoption of solar energy, given the current urgency to deploy new carbon-free energy sources says Vladimir Bulović, lead author of the article.
How it works ?
This is not the first attempt by this team of researchers to develop ultralight solar panels. They had indeed already managed to create extremely light solar cells (you might put it on a soap bubble!). But its manufacture required complex and costly processes to set up.
This time around, they turned to a method that was easy to replicate on a large scale. To manufacture their solar cells, they therefore use nanomaterials, in the form of a conductive “ink”. The cell is therefore “printed” using this ink. Using a machine, they deposit thin layers of nanomaterials on a substrate (a sheet of plastic layer) prepared upstream. Using screen printing (a technique similar to how designs are added to screen printed t-shirts), an electrode is deposited on the structure to complete the solar module.
Then the researchers can peel their printed module, which is regarding 15 microns thick, from the plastic substrate. It then forms a very light solar device, thinner than a human hair. Then, the challenge is to prevent it from tearing too easily. The scientists therefore decided to attach it to a fabric that is both light and resistant: more precisely, a composite fabric that weighs only 13 grams per square meter, commercially known as Dyneema. ” This fabric is made of fibers so strong they were used as ropes to lift the sunken cruise ship Costa Concordia from the bottom of the Mediterranean Sea “, specifies the MIT. In order to fix these two materials together, the researchers used a UV-curing glue.
Why not print directly onto the fabric, you might ask? ” While it may seem simpler to print the solar cells directly onto fabric, this would limit the selection of possible fabrics or other receiving surfaces to those that are chemically and thermally compatible with all of the processing steps required to fabricate the devices. . Our approach separates the manufacture of solar cells from their final integration », Explains on this subject Mayuran Saravanapavanantham.
The tests carried out on this solar fabric are rather conclusive in terms of durability. Scientists have tested its abilities by rolling and unrolling it more than 500 times. The cells, they claim, have retained more than 90% of their energy-producing capacity. A downside, however, tarnishes this picture. The material used to make the cells might be altered by interacting with humidity and oxygen in the air. However, if they are covered with a heavy protective layer, like conventional solar panels, this takes away all interest from the technology. “ The team is currently developing ultra-thin packaging solutions that would only marginally increase the weight of current ultra-light devices. “So answer the researchers.
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