Structural supercapacitor usable in a mechanical structure

Abstract

According to the invention there is provided a component including a supercapacitor and a method of producing same. The component comprises a first (12) and second (14) electrode and a separator structure (16) which separates the two electrodes and contains a liquid or gel electrolyte. The first and second electrode structures are each formed from a composite material (10) which includes electrically conductive fibers and electrochemically active material in a binder matrix and the supercapacitor is formed to be structurally inseparable from the rest of the component. Further, the component forms a structural capacitor. The obtained structural capacitor could be used in aircraft structure to save weight.

Claims

1. A component comprising a structural supercapacitor included in said component, the structural supercapacitor including: a first electrode structure; a second electrode structure; and a separator structure; said separator structure being formed from a composite material comprising a glass fibre ply in a cured electrically insulating separator binder matrix; said separator structure separating the first electrode structure from the second electrode structure; said separator structure further comprising at least one void which comprises a fluidic electrolyte; each of the first electrode structure and the second electrode structure comprising at least one ply of conductive composite material which includes electrically conductive fibres in a cured, electrically insulating electrode binder matrix; and the supercapacitor being structurally inseparable from a remainder of the component.

2. The component according to claim 1, wherein said at least one void is formed from interstices of a separator structure that is partially bonded to the first electrode structure or the second electrode structure.

3. The component according to claim 1, wherein at least one of the first electrode structure, the second electrode structure, and the separator structure comprises a porous additive which increases access of the electrolyte into said structure.

4. The component according to claim 1, wherein at least one of the first electrode structure and the second electrode structure further includes an electrically conductive additive.

5. The component according to claim 1, wherein: the electrically insulating binder matrix is a polymer, ceramic, or glass.

6. The component according to claim 1, wherein at least one of the first electrode and the second electrode comprises and is electrically connected to a further at least one electrically conductive fibre ply.

7. The component according to claim 6, wherein at least one of the electrically conductive fibre plies is a carbon fibre ply.

8. The component according to claim 1, wherein the separator structure comprises a microporous polymer film.

9. The component according to claim 1, wherein the separator structure includes an electrically insulating binder matrix material that is a viscosity modified curable resin.

10. The component of claim 1, wherein the separator binder matrix and the electrode binder matrix form a common binder matrix.

11. A panel on a vehicle, vessel, or craft comprising at least one component, said component including a structural supercapacitor including: a first electrode structure; a second electrode structure; and a separator structure; said separator structure being formed from a composite material comprising a glass fibre ply in a cured electrically insulating separator binder matrix; said separator structure separating the first electrode structure from the second electrode structure; said separator structure further comprising at least one void which comprises a fluidic electrolyte; each of the first electrode structure and the second electrode structure comprising at least one ply of conductive composite material which includes electrically conductive fibres in a cured, electrically insulating electrode binder matrix; and the supercapacitor being structurally inseparable from the rest of the component.

12. The panel of claim 11, wherein the separator binder matrix and the electrode binder matrix form a common binder matrix.

13. A method of manufacturing a component including, and being structurally inseparable from, a supercapacitor, the method comprising: providing a separator structure comprising fibrous reinforcing material and plastic matrix material; laying up, on either side of the separator structure, a layup of plies of electrically conductive fibrous reinforcing material; introducing an electrode binder matrix into said plies, thereby forming first and second electrodes that are separated from each other by the separator structure; and consolidating and curing the first electrode, second electrode and separator structure into a single composite component; said separator structure, after curing, further comprising at least one void that is able to accommodate a liquid electrolyte.

14. The method according to claim 13, further comprising inserting a liquid or gel electrolyte into said at least one void.

15. The method of claim 13, wherein curing the first electrode, second electrode and separator structure into a single composite component includes forming a common binder matrix from the plastic binder material and the electrode binder matrix.

Description

(1) Exemplary embodiments of the component in accordance with the invention will now be described with reference to the accompanying drawings in which:—

(2) FIG. 1 shows a cross sectional side view of a component integral with a supercapacitor, according to the invention, and

(3) FIGS. 2a and 2b shows a partially bonded separator structure to encapsulate a liquid electrolyte.

(4) The invention provides components comprising a structural supercapacitor using formed at least in part from composite materials, thereby imparting desired structural properties. FIG. 1 shows an example of a component integral with supercapacitor of the invention, depicted generally at 10, comprising a first electrode structure 12 which is spaced apart from a second electrode structure 14 by a separator structure 16. The first and second electrode structures 12, 14 may be connected to suitable electrode contacts 18, 20 to permit charging and discharging of the supercapacitor in the usual manner, although, as explained in more detail below, the first and second electrode structures 12, 14 may act fully as current collectors.

(5) Each of the first and second electrode structures 12, 14 and the separator structure 16 are formed as a composite material comprising suitable fibres in a binder matrix. The first and second electrode structures 12, 14 may optionally comprise electrically conductive fibres 12a, 14a in respective binder matrices 12b, 14b. The separator structure 16 comprises electrically insulating fibres 16a in a binder matrix 16b. The fluidic electrolyte 17 is located within the supercapacitor 10, in a void within the separator structure 16.

(6) The fluidic electrolyte can be accommodated in a number of ways. The separator structure may be partially bonded in order to provide spaces which can be filled by the electrolyte. The electrolyte is retained by capillary action between fibres. A 30 to 40% degree of bonding is suitable for this purpose. A porous additive, such as a silica or a silica gel, may be used to provide a more open cell structure or a microporous polymer film may be employed. Vents may be provided to control the release of gases during overcharge conditions and fill/drain ports may be fitted to permit the introduction and removal of the aqueous electrolyte for maintenance or storage.

(7) The component of the invention can be manufactured in different ways. For example, it is possible to fully manufacture each of the first and second electrode structures and the separator structure separately and subsequently bond these completed structures together. Alternatively, each structure may be produced separately, but with partial cure of the binder matrices, so that the structures can be co-cured together. The entire structure of the first and second electrodes and separator structures may be formed with a common binder matrix, for example in a wet lay up process, to provide a ‘monolithic’ structure for the component.

(8) Other electrolyte systems may be used. For example, a porous separator structure may be produced by using an open cell foam. A gel electrolyte may be produced by adding gelling agents to an aqueous electrolyte solution.

(9) The first and second electrodes and separator structures are not necessarily planar. Non-planar configurations may be employed, for example, to provide a curved or even a generally tubular structure. The composite structures of the invention are well suited for such configurations. The device may comprise a number of electrodes and may be formed with integral electrochemical cells.

(10) FIG. 2a shows a capacitor structure 20, with a first electrode structure 24 and second electrode structure 22, as described in FIG. 1. The electrodes sandwich a partially bonded separator structure 26, the layer has a plurality bonding site 21 which enables the adhesion of the separator structure 26 and first and second electrode structures 22, 26. The open bonding sites 21 will create open cavities which can be filled with a fluidic electrolyte 27.

(11) FIG. 2b shows a plan view of the partially bonded separator structure 26, where the bonding sites 21, may define small cavities 28 or a larger cavity 29, which are then capable in the final device of being filled with liquid electrolyte 27. The balance of strength of the composite structure and capacitance will determined the degree of bonding required in the partially bonded separator structure 26 and the volume of fluidic electrolyte.