These shorts and sleeping bag charge your mobile devices

  • Smart materials in the Power Shorts use kinetic energy created by the wearer’s movements to charge mobile phones
  • Modules attached to the fabric of the Recharge Sleeping Bag capture thermal energy from a sleeper’s body to create an electric charge
  • Products have been developed by Vodafone and Southampton University

By Victoria Woollaston

Festival goers need never run out of phone battery again thanks to a new range of denim shorts and sleeping bags that use body heat and movement to generate electricity.

The Power Shorts and Recharge Sleeping Bag can charge a phone’s battery by harvesting energy from the human body using kinetic and thermoelectric technology.

The wearable phone chargers have been designed by mobile phone company Vodafone with help from the University of Southampton.

Vodafone has teamed up with the University of Southampton to create wearable phone chargers for festival goers. The Power Shorts, pictured, capture kinetic energy from the wearer’s body movements. This energy can then be used to charge mobile handsets This image explains how the Power Shorts work. They are fitted with foam-like ferroelectret smart materials which contain voids. The surfaces of these voids are permanently charged and as the size and shape of the voids in the shorts changes,when they’re squashed or deformed, a charge is produced

  • powerpocket2The Power Shorts are fitted with foam-like ferroelectret materials.
  • As the wearer moves, the shorts gather kinetic energy when these ferroelectret materials are squashed or deformed.
  • These foam-like materials contain voids.
  • The surfaces of these voids are permanently charged and exhibit piezoelectric and pyroelectric properties.
  • The word piezoelectricity means electricity resulting from pressure.
  • When pressure is applied to the materials in the shorts they generate an electric charge.
  • As the size and shape of the voids in the shorts changes this creates the electricity needed to charge the phone attached to the shorts by a connector inside the Power Pocket.

The Recharge Sleeping Bag harvests thermal energy using the ‘Seebeck Effect’.

This effect creates pyroelectricity, which is the ability of certain materials to generate a temporary charge when they are heated up or cooled down.

In the case of the sleeping bag, this process monitors the change of temperature through a thermoelectric module fitted to the fabric of the bag.

Heat from the sleeper’s body flows through this module contained within a multi-layered ‘power felt’.

This felt contains polymer films and two semi conductors that generate an electric charge as they heat up.

Trials conducted by Vodafone found that a full day’s walking and dancing while wearing the shorts can provide enough energy to charge a phone for four hours.

While heat from a night in the sleeping bag is said to create 11 hours of charge.

Prof Stephen Beeby from the university said: ‘We’re exploring two specific technologies to charge the Power Pocket – thermoelectrics and kinetic energy harvesting.

‘Both represent cutting-edge research around smart fabrics and, in this case, we’re looking to integrate these into a sleeping bag and a pair of denim shorts.’

Vodafone’s Christian Cull added: ‘Our ambition was to create a practical but exciting solution to the charging-related issues experienced by many at outdoor events.

‘We hope people harness the power in their pocket to keep them chatting, texting, browsing and photographing throughout the entire festival season.’

The ‘smart fabric’ technology will be unveiled ahead of this weekend’s Isle of Wight Festival and will continue to be developed throughout the summer.


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