The present invention relates to an energy storage device and to a coated web for an energy storage device.

The demand for sources of renewable energy has driven significant improvements in the cost and efficiency of solar photovoltaic cells but existing technology still represents a relatively expensive method of generating electricity.

The demand for sources of renewable energy has also driven improvements in energy storage. The efficiency of energy storage must be increased and/or the cost of energy storage must be decreased, if renewable energy is going to meet more of the world’s energy demand.

The present invention aims to mitigate one or more of the disadvantages of existing energy storage devices.

In accordance with a first aspect of the present invention there is provided an energy storage device comprising:

a flexible substrate comprising at least two patterned regions spaced apart from one another along the length of the flexible substrate;

each patterned region comprising at least one groove extending in the longitudinal direction of the substrate (web direction) having a first and a second face;

wherein the first and second faces are each coated with a conductor such that there is no direct electrical communication between the conductors on the first and second faces; wherein the at least one groove contains a material for storing electrical potential energy (e.g. capacitor material); wherein the conductors on the first and the second face of the at least one groove of each patterned region are each in electrical connection with an electrical conductor at opposing edges of the flexible substrate; wherein the first and the second patterned region are electrically connectable to one another.

The at least one groove provides the patterning in the patterned region.

When referred to herein,“web direction”,“longitudinally” and“length” all relate to the longest dimension of the flexible substrate and/or the coated web. “Transversely” relates to a direction across the shortest dimension of the flexible substrate and/or the coated web in a direction perpendicular to the web direction.

In certain embodiments the first and the second patterned regions are electrically connectable to one another in series or in parallel electrical connection. More specifically, the at least one groove in each of the at least two patterned regions is electrically connectable to a further at least one groove in a patterned region. Yet more specifically, at least one groove in a patterned region is electrically connectable to another at least one groove in a further patterned region in series or in parallel electrical connection. In this way, when grooves in two separate patterned regions are in series electrical connection with one another, following the electrical conduction paths provided for electrical conduction each of the grooves in the patterned regions is arrived at successively. When grooves in two separate patterned regions are in parallel electrical connection with one, following the electrical conduction path between the grooves in the patterned regions, any of the grooves in the patterned regions can be arrived at by the electrical charge without having the cross any other one groove in any of the at least two patterned regions.

In certain embodiments, the first and second patterned regions are electrically connected to one another in series by a conductor material on the surface of the substrate between adjacent patterned regions.

In certain embodiments the conductor material is deposited on the surface of the substrate.

In certain embodiments the conductor material is printable conductive material. Yet more specifically, the conductor material is conductive ink.

In certain embodiments, the conductor material is coated, that is to say forms a coating, onto the substrate surface.

In certain embodiments, the conductor material is a conductive foil. More specifically, the conductive foil is laminated along the edges of the patterned region(s). More specifically, the conductive foil is formed of strips electrically connecting the edges of adjacent patterned regions. In this way, electrical connections between adjacent patterned regions are formed by the interconnecting conductive foil strips. Certain connections can be disconnected between patterned regions by removing (i.e. breaking) the conductive foil between the regions (e.g. by scratching or lasering the conductive foil off). In certain embodiments the conductive foil is a conductive metal foil.

In certain embodiments, the conductor material on the first face of the at least one groove extends to an edge of the patterned region. This conductor does not however coat the very extreme ends of the at least one groove.
Claims

1. An energy storage device comprising:

a flexible substrate comprising at least two patterned regions spaced apart from one another along the length of the flexible substrate;

each patterned region comprising at least one groove extending in the longitudinal direction of the substrate (web direction) having a first and a second face;

wherein the first and second faces are each coated with a conductor such that there is no direct electrical communication between the conductors on the first and second faces; wherein the at least one groove contains a material for storing electrical potential energy (e.g. capacitor material); wherein the conductors on the first and the second face of the at least one groove of each patterned region are each in electrical connection with an electrical conductor at opposing edges of the flexible substrate; wherein the first and the second patterned region are electrically connectable to one another.

2. An energy storage device according to claim 1 , wherein the first and the second patterned regions are electrically connectable to one another in series or in parallel electrical connection.

3. An energy storage device according to claim 1 or claim 2, wherein the first and second patterned regions are electrically connected to one another in series by a conductor material on the surface of the substrate between adjacent patterned regions.

4. An energy storage device according to any one of claims 1 to 3, wherein the conductor material on the first face of the at least one groove extends to an edge of the patterned region and the conductor material on the second face of the at least one groove extends to an edge of the patterned region.

5. An energy storage device according to any one of claims 1 to 4, wherein the conductor material on the first face of the at least one groove extends to an edge of the patterned region thereby defining a positive pole of the patterned region in electrical communication with one of the faces of the groove and the conductor material on the second face of the at least one groove extends to an opposing edge of the patterned region thereby defining a negative pole of the patterned region in electrical communication with other face of the groove.

6. An energy storage device according to any one of claims 1 to 5, wherein the ends of each groove are free from conductor material.

7. An energy storage device according to any one of claims 1 to 6, wherein the first and second patterned regions are electrically connected to one another in series by a conductor material through the thickness of the substrate.

8. An energy storage device according to any one of claims 1 to 7, wherein each patterned region comprises a series of grooves.

9. An energy storage device according to any one of claims 1 to 8, wherein the flexible substrate comprises three or more patterned regions spaced apart from one another along the length of the flexible substrate.

10. An energy storage device according to any one of claims 1 to 9, wherein adjacent patterned regions are electrically connected in series.

11. An energy storage device according to any one of claims 1 to 10, wherein adjacent patterned regions are electrically connected in parallel.

12. An energy storage device according to any one of the preceding claims 1 to 7, wherein each patterned region comprises one or more unit cells.

13. An energy storage device according to claim 12, wherein each unit cell is electrically connected to one or more other unit cells in the patterned region.

14. An energy storage device according to claim 12 or claim 13, wherein each unit cell comprises a groove or a series of electrically connected grooves.

15. An energy storage device according to any one of claims 12 to 14, wherein each patterned region comprises a plurality of unit cells arranged longitudinally along the web.

16. An energy storage device according to any one of claims 12 to 15, wherein each patterned region comprises a plurality of unit cells arranged transversely across the web.

17. An energy storage device according to claim 16, wherein the plurality of unit cells arranged transversely across the web are electrically connected to one another in series.

18. An energy storage device according to any one of claims 12 to 17, wherein each patterned region comprises a plurality of unit cells arranged longitudinally down the web which, when the flexible substrate is rolled at the point of assembly, are electrically connected to one another in parallel.

19. An energy storage device according to any one of the preceding claims, wherein the first and/or second face of the groove(s) is profiled (e.g. engineered, roughened, textured).

20. A coated web for an energy storage device comprising:

a flexible substrate comprising at least two patterned regions separable from one another and arranged transversely across the width of the flexible substrate;

each patterned region comprising at least one groove having a first and a second face; wherein the first and second faces are each coated with a conductor such that there is no direct electrical communication between the conductor on the first and second faces; wherein the at least one groove contains material for storing electrical potential energy (e.g. capacitor material); and wherein first and the second face of the at least one groove of each patterned region are each in electrical connection with an electrical conductor coating layer on the surface of the flexible substrate, and wherein the flexible substrate comprises at least one deformation in the electrical conductor and the flexible substrate and adjoining adjacent patterned regions.

21. A coated web according to claim 20, comprising flexible polymer or other electrically insulating substrate.

22. A coated web according to claim 20 or claim 21 , wherein the at least one deformation forms a line of weakening between the adjacent patterned regions arranged transversely across the width of the flexible substrate.

23. A coated web according to claim 22, wherein the line of weakening is parallel to the longitudinal axis of the flexible substrate.

24. A coated web according to any one of claims 20 to 23, wherein the at least one deformation is an aperture, a recess, a dimple of the like.

25. A coated web according to any one of claims 20 to 24, wherein the flexible substrate comprises at least one aperture therethrough.

26. A coated web according to claim 25, wherein the at least one aperture is located in a patterned region.

27. A coated web according to claim 25 or claim 26, wherein each patterned region comprises at least one aperture therethrough.

28. A coated web according to any one of claims 20 to 27, wherein the flexible substrate comprises a plurality of apertures through the flexible substrate at each opposing edge.

29. A coated web according to any one of claims 25 to 28, wherein each aperture comprises an aperture wall.

30. A coated web according to claim 29, wherein the aperture wall is coated with a conductor material.

31. A coated web according to claim 29 or claim 30, wherein the aperture wall is profiled (e.g. engineered, roughened, textured).

32. An energy storage device comprising:

a flexible substrate comprising at least two grooves in a surface thereof, each groove having a first and a second face;

each of the grooves being spaced apart from one another along their length providing an inter-groove spacing therebetween;

wherein each groove contains a material for storing electrical potential energy (e.g. capacitor material) and the material for storing electrical potential energy overfills each groove such that the material provides a layer of material for storing electrical potential energy over at least a portion of the substrate surface adjacent the first and the second faces of each groove and the inter-groove spacing, wherein the ratio of the inter-groove spacing to the depth of the layer of material for storing electrical potential energy is at least 1 :1.

33. An energy storage device according to claim 32, wherein the ratio of the inter-groove spacing to the depth of the layer of material for storing electrical potential energy is between about 1 : 1 and about 5: 1.

34. An energy storage device according to claim 32 or claim 33, wherein the ratio of the inter-groove spacing to the depth of the layer of material for storing electrical potential energy is at least 2:1.

35. An energy storage device according to any one of claims 32 to 34, wherein the depth of the layer of material for storing electrical potential energy is less than about 10 microns.

36. An energy storage device according to claim 35, wherein the depth of the layer of material for storing electrical potential energy is between about 2 microns and about 20 microns.

37. An energy storage device according to any one of claims 32 to 36, wherein the flexible substrate comprises an overlayer.