Battery cell comprising an ultra thin layer of carbon fibers

Abstract

A battery cell includes an anode, a cathode, and a separator between the anode and the cathode, wherein at least one of the anode or the cathode includes at least a carbon fiber ply comprising carbon fibers, the carbon fiber ply having a thickness of less than 90 micrometers. Also disclosed are a battery and an aircraft including such battery cell, and a method for manufacturing such battery cell.

Claims

1. A battery cell comprising: an anode; a cathode; a separator between the anode and the cathode; and a solid-state polymer layer forming a first electrolyte between the anode and the separator, and a solid-state polymer layer forming a second electrolyte between the cathode and the separator; wherein the anode and the cathode each comprises a carbon fiber laminate, wherein the carbon fiber laminate comprises a plurality of carbon fiber plies comprising carbon fibers, each carbon fiber ply having a thickness of equal to or less than 90 micrometers, wherein each carbon fiber ply comprises a spread tow tape having a thickness of less than 40 micrometers.

2. The battery cell according to claim 1, wherein the separator comprises at least a glass fiber ply comprising glass fibers, the glass fiber ply having a thickness of equal to or less than 100 micrometers.

3. The battery cell according to claim 1, wherein the cathode comprises carbon fibers coated with a ferritic oxide.

4. The battery cell according to claim 1, wherein the carbon fibers have an average diameter of between 1 and 10 micrometers.

5. The battery cell according to claim 1, wherein the carbon fiber ply has an area weight of equal to or less than 100 grams per square centimeter (g/cm.sup.2).

6. A battery comprising at least one battery cell according to claim 1.

7. An aircraft comprising at least one structural part comprising at least a battery cell according to claim 1.

8. A method for manufacturing a battery cell comprising: forming an anode; forming a cathode; obtaining a separator and placing the separator between the anode and the cathode; forming a first electrolyte by layering a solid-state polymer layer between the anode and the separator and forming a second electrolyte by layering a solid-state polymer layer between the cathode and the separator; spreading a tow comprising carbon fibers for obtaining a thin carbon fiber ply, the thin carbon fiber ply having a thickness of less than or equal to about 90 micrometers and the tow having a thickness of less than 40 micrometers; integrating a plurality of the thin carbon fiber plies as a carbon fiber laminate into the anode and into the cathode for forming the anode and the cathode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Some specific example embodiments and aspects of the disclosure herein are described in the following description in reference to the accompanying figures.

(2) FIG. 1 is a schematic representation of a cross-section of a battery cell embodiment according to the disclosure herein.

(3) FIG. 2 is a schematic representation of a battery comprising a plurality of battery cells according to the disclosure herein.

(4) FIG. 3 is a schematic representation of a laminate of a battery electrode according to the disclosure herein.

(5) FIG. 4 is a schematic representation of a step for spreading a tow of a method according to the disclosure herein.

DETAILED DESCRIPTION

(6) In FIG. 1 a battery cell 1 is represented which comprises a cathode 3, an anode 4, and a separator 5. The separator is separated from the anode and the cathode respectively by two electrolytes 6.

(7) The anode 4 and the cathode 3 have each been obtained by the lamination of eight plies of carbon fiber spread tow tapes, impregnated with a matrix such as for example a resin of HexFlow® RTM6 commercialized by Hexcel®.

(8) The carbon fiber laminate may be of the type described with FIG. 3. After impregnation, the laminated may be cured by application of heat and/or pressure for example.

(9) Previous to the impregnation of the carbon fiber plies of the cathode 3, these may be coated with a ferritic oxide, for example by bathing the carbon fiber plies in a liquid solution comprising ferritic oxide.

(10) The total thickness of the anode 4 may be of about 650 micrometers. The total thickness of the battery cell shown on FIG. 1 may be less than 4.0 mm, for example of about 2.0 mm.

(11) Similarly the separator 5 may have been obtained by the lamination of eight plies of glass fiber spread tow tapes, impregnated with a matrix such as for example a resin of HexFlow® RTM6 commercialized by Hexcel®.

(12) Other elements of the battery cell such as charge collectors and electrical connectors are not represented.

(13) In FIG. 2 a battery 2 comprising a plurality of anodes 4 and cathodes 3 is represented. Each pair of cathode and anode is separated by a separator 5 and two layers of electrolytes 6. The anodes 4 and cathodes 3 situated between two successive separators 5 are part of two battery cells (one on each of their faces) simultaneously.

(14) The total thickness of the battery shown on FIG. 2 may be less than 10 mm, in particular less than 2 mm, for example of about 0.65 mm. This very low thickness of a battery may allow to ingrate such battery in many different places of a vehicle, in particular of an aircraft. Besides such battery has high mechanical resistance, due to the high mechanical resistance of each of its layer, and in particular due to the high mechanical resistance of the carbon fiber laminate integrated in the electrodes 3, 4 of the battery cells. Such battery may thus for example form a portion of a wing skin, of a fuselage, of a cabin floor or of a frame of an aircraft.

(15) The compactness, alignment and low thickness of fiber plies also allows a higher energy density. The energy density of the battery cell is thus higher than the energy density of conventional battery cells. The energy density of such battery is estimated to be multiplied by up to 2 compared to batteries using conventional thick carbon fiber plies.

(16) In FIG. 3, a laminate 7 for an anode or a cathode of a battery cell according to the disclosure herein is represented.

(17) The laminate 7 comprises a plurality of carbon fiber plies 8, 9, 10, 11, 12, 13, 14, 15. Each carbon fiber ply is made of a plurality of carbon fibers 17, the carbon fibers being for the most part generally oriented along a predetermined direction in the ply.

(18) In the example of FIG. 3 each ply comprises about 2 carbon fibers in its thickness. Each carbon fiber may have an average diameter of about 6 micrometer, such that the total thickness of each carbon fiber ply may be of about 12 micrometer. The total thickness of the carbon fiber laminate 7 may thus be of less than 100 micrometer, for example of about 96 micrometer.

(19) Each carbon fiber ply may be pre-impregnated with a HexFlow® RTM6 resin commercialized by Hexcel®. Eight carbon fiber plies may then be stacked and laminated together.

(20) A carbon fiber laminate may be obtained for example by a process in which resin is impregnated into the carbon fiber plies under pressure. To do so, the preform is enclosed to a vacuum bag or laid into a closed tool. The textile preform comprising carbon fiber plies and the resin are preheated to 120° C. A pressure differential is applied between the resin pod and the preform (vacuum or pressure) so as to obtain an impregnation of the fiber plies by the resin. After impregnation, the impregnated laminate is heated up to 180 degrees Celsius, and cured for 90 minutes. It is afterwards cooled down to less than 70 degrees Celsius and de-molded.

(21) The carbon fiber plies may be arranged so as to increase the mechanical resistance of the laminate. In particular, if a first carbon fiber ply 15 is disposed with its carbon fiber in a predetermined direction of reference at zero degrees, a second carbon fiber ply 14 may be placed on it with fibers oriented at 90 degrees, a third carbon fiber ply 13 may be placed on it with fibers oriented at 45 degrees, a fourth carbon fiber ply 12 with fibers oriented at 135 degrees, a fifth carbon fiber ply 11 with fibers oriented at 45 degrees, a sixth carbon fiber ply 10 with fibers oriented at 135 degrees, a seventh carbon fiber ply 9 with fibers oriented at 90 degrees, an eighth carbon fiber ply 8 with fibers oriented at zero degrees. Thereby the mechanical resistance of the laminate is increased in multiple directions.

(22) In FIG. 4 a step of spreading a carbon fiber tow is represented. In this step a carbon fiber tow 16 is submitted to an air flow 18 in an orthogonal direction compared to the longitudinal direction of the carbon fiber tow 16. The suction of the air flow 18 on the sides of the carbon fiber tow 16 leads to the detachment of some carbon fibers 17 on each side of the carbon fiber tow 16, towards directions orthogonal to the air flow 18 and orthogonal to the longitudinal direction of the carbon fiber tow 16. During the process the carbon fibers 17 of the carbon fiber tow 16 are separated from each other in a flat configuration leading to the formation of a spread tow tape of carbon fibers 17. Such spread tow tape may then be used to form a carbon fiber ply.

(23) The disclosure herein is not limited to the specific embodiments herein disclosed as examples. The disclosure herein also encompasses other embodiments not herein explicitly described, which may comprise various combinations of the features herein described.

(24) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.