Energy storage device

1. An energy-storage device including a charge-storing supercapacitor cell comprised of electrodes at least one of which includes activated carbon having a high surface area and a nano-carbon component, an ion permeable membrane and an electrolyte characterised in that the cell including the electrodes and ion permeable membrane is encapsulated in a rigid polymer matrix, wherein the matrix is conductive; and wherein (i) the matrix comprises a conductive polymer; (ii) the matrix comprises carbon fibre; or (iii) the matrix comprises metal powders, foils, rods or meshes made of conducting metal.

2. An energy-storage device as claimed in claim 1 characterised in that the nano-carbon component includes carbon nanotubes, graphene or a mixture thereof.

3. An energy-storage device as claimed claim 1 characterised in that the charge-storing cell comprises a polymer pouch in which the electrode(s) and the electrolyte are contained.

4. An energy-storage device as claimed in claim 1 characterised in that matrix defines at least one void for containing the electrolyte.

5. An energy-storage device as claimed in claim 1 characterised in that matrix is a composite structure including the electrolyte in gel or polyelectrolyte form, the electrodes and a polymer component providing structural rigidity.

6. An energy-storage device as claimed in claim 1 characterised in that the matrix is coated with a water- and/or oxygen-impermeable barrier layer.

7. An energy-storage device as claimed in claim 1 characterised in that the matrix is reinforced by including rigid metal or polymer inserts or by employing self-supporting electrodes and/or polymer membranes.

8. An energy-storage device as claimed in claim 1 characterised in that the electrode is a woven, non-woven or electrospun cloth or mat and the matrix is comprised of a polymeric electrolyte.

9. An energy storage device as claimed in claim 1 characterised in that the rigid matrix is a carbon fibre matrix and exposed carbon fibres on a surface thereof act as a current collector for the electrodes.

10. An energy storage device as claimed in claim 1 characterised in that the charge-storing supercapacitor cell has an equivalent series resistance of less than 30 Ohms measured over 100 cycles of charge and discharge; and a specific conductance of greater than 100 Farads per gram and an energy storage capacity of greater than 6 Wh/kg at an operating voltage of 3.5 Volts.

11. A body part for a transportation vehicle characterised by comprising an aerodynamically-shaped rigid matrix element which encapsulates at least one charge-storing supercapacitor cell as defined in claim 1 , wherein the electrodes and ion permeable membrane of the supercapacitor cell are encapsulated by the rigid matrix element.

12. A body part as claimed in claim 11 characterised by having a drag coefficient in the range 0.7-0.2.

13. A body part as claimed in claim 11 characterised by further comprising a photovoltaic cell which is attached to or disposed within at least one surface of the element and which is in electrical contact with the charge-storing supercapacitor cell.

14. A body part of claim 13 characterised by having a drag coefficient in the range 0.7-0.2.

15. A body part as claimed in 11 characterised by further comprising a connector for electrically connecting it to another body part or an electrical component of the transportation vehicle.

16. A body part of claim 15 characterised by having a drag coefficient in the range 0.7-0.2.