WO2013124454A1

WO2013124454A1 - Method for producing a graphite film, a graphite film produced using this method, and the use thereof

Info

Publication number: WO2013124454A1
Application number: PCT/EP2013/053623
Authority: WO
Inventors: Oswin ÖTTINGER; Rainer Schmitt; Bastian Hudler; Sylvia Mechen; Werner Langer; Jürgen Bacher
Original assignee: Sgl Carbon Se
Priority date: 2012-02-22
Filing date: 2013-02-22
Publication date: 2013-08-29
Also published as: DE102012202748A1

Abstract

The invention relates to a method for producing a graphite film consisting at least partially of compressed graphite expandate, comprising an expanding step of graphite salt and a compressing step of the graphite expandate that is formed in the expanding step. In the expansion step, graphite salt particles are expanded on a base into graphite expandate, the graphite expandate remains on the base and is compressed on the base in the compressing step into the graphite film. The invention further relates to a graphite film produced using this method and to the use thereof.

Description

METHOD FOR THE PRODUCTION OF A GRAPHITE FILM, A GRAPHITE FILM MANUFACTURED THEREOF, AND THEIR USE

The present invention relates to a process for producing a graphite foil according to the preamble of claim 1, a graphite foil prepared by this process and their use.

Graphite foil is conventionally produced by compression of so-called graphite expandate. Natural graphite is transformed by treatment with acid to graphite salt, which is an intercalation compound of graphite and the corresponding acid. These graphite intercalation compounds (hereinafter referred to as graphite salt for short) are made to swell by heat treatment, for example, 200 times the original volume. The resulting flakes of expanded natural graphite (hereinafter also called graphite expandate) with a very low bulk density of, for example, 1 to 20 g / l can interlock by pressing into each other and form a mechanically stable, but very flexible graphite foil without the addition of binder.

Conventionally, graphite foils are usually produced in the thickness range of 0.5 to 3.0 mm. These graphite foils are widely used, for example for seals or as heat spreaders. Due to a high anisotropy of the thermal conductivity by aligning the graphite particles and thus levels during pressing, graphite foil as heat spreader can dissipate and distribute heat very well. This is useful, for example, to avoid local overheating in a variety of applications, such as screens.

To produce graphite foils lesser thickness than 0.5 mm, in particular less than 0.2 mm thickness, has previously succeeded only with great technical effort and especially at low thicknesses with non-optimal qualities. DE 690 12 675 T2 describes a graphite foil with a thickness of less than 0.2 mm, which is produced by heating graphite salt very quickly by direct introduction into a hot zone as a modification of the method described above. With this In particular with very thin films, the process is difficult to maintain a homogeneity of the mechanical strength in relation to the film surface.

JP-A-61-133865 proposes a process for producing thin graphite films below 0.254 mm (10 mils) by applying an adhesive layer and expanded graphite to a polyester film, metal foil or paper tape before the graphite foil becomes the desired one Thickness of 0.254 mm is rolled out. The method has the disadvantage that an adhesive layer is necessary, which makes it difficult to separate a resulting graphite foil from the carrier material. In addition, with the method no homogeneous thicknesses below 0.254 mm or basis weights below 200 g / m ^{2 can be} achieved.

In a conventional expansion of graphite salt in a flame tube and transferring the resulting Graphitexpandats via a chute into a supercharger, which then makes a first compaction of the expandate on calender rolls, the amount of graphite expandate particles can be controlled poorly at low basis weights. In particular, difficult-to-control flow conditions in the chute or supercharger necessitate a strongly fluctuating weight per unit area at low amounts of expanded material.

The object of the invention is to overcome the stated problems of the prior art, in particular to provide a method with which a graphite foil of high quality with a basis weight less than 200 g / m ² , in particular less than 150 g / m ² , can be produced. Preferably, with the method a self-supporting graphite foil, in particular with a thickness of less than 200 μιτι, be continuously produced.

The problem is solved by a method according to claim 1, i. one

A process for the production of a graphite foil from at least partially compressed graphite expandate, comprising an expanding step of graphite salt and a compressing step of the expanding graphite expander, characterized in that in the expansion step graphite salt particles are expanded on a base to graphite expander, the graphite expander remains on the base and in the compression step on the base to the graphite foil is compressed. Advantageous developments of the method according to the invention are specified in the dependent claims 2 to 9.

The process according to the invention is characterized in that, in the expansion step, graphite salt particles are expanded on a support to expand graphite, the graphite expander remains on the support and is compressed on the support to the graphite foil in the compression step.

Thus, surprisingly, a particularly homogeneous graphite foil can be produced, even with a small thickness of, for example, less than 200 μm and with a low basis weight, such as below 150 g / m ² .

By carrying out the expansion of the graphite intercalation compounds on the same support as the subsequent compression, the expansion graphite particles can be compacted without having to be transported to a compression unit physically separate from the manufacturing location, as in conventional manufacturing processes.

As a result, a graphite foil having a good homogeneity characteristic of the method according to the invention is achieved, and surprisingly even at very low basis weights. This is probably also facilitated by the fact that the graphite salt particles can be distributed much more uniformly than the weight-related same amount of corresponding expandate particles. After the expansion step of the graphite salt particles originally distributed uniformly on the support, there are correspondingly uniformly or homogeneously distributed graphite expandate particles on the support, which do not have to be moved further until they expand and afterward. Such a uniform distribution is not possible by direct application of graphite expandable particles to a substrate (ie, after expansion), because graphite expandate particles with their accordion-like surface and low density undesirably become entangled with each other even prior to the compacting step with simple contact, resulting in localized aggregates or non-existing ones Places on the pad would result. These local clumps or remaining parts in turn would become holes or inhomogeneities in subsequent compression Lead graphite foil. This finding, which was obtained in the context of the invention, has made the present invention possible. The aforementioned suspected mechanisms are not to be seen as limiting the invention. The homogeneity of the graphite foil relates both to its thickness and basis weight as well as to other properties, such as its thermal conductivity in the film plane and perpendicular to the film plane, and its mechanical strength, in particular its tensile strength. A further advantage of the method according to the invention is that it allows a self-supporting graphite foil to be obtained even with a very low basis weight. In the context of the invention, "self-supporting" means that, because of the high intrinsic stability of the resulting graphite foil, no second layer is necessary to support the graphite foil obtained by compression for handling, rather, the graphite foil can be removed from the substrate without remaining attached to it This unsupported property is advantageously possible due to the surprisingly high strength of the graphite foil according to the invention, even at low thicknesses. that the graphite expandate particles are not moved after their expansion and therefore are not damaged before compression or at least hardly damaged.

Alternatively, however, it is also possible to combine a graphite foil obtained with the method according to the invention with at least one further layer to form a multi-layer structure, if desired.

Advantageously, the expansion step and / or the compression step are continuous. This is possible, in particular, in that the graphite pandate formed on the substrate remains thereon until the compression step. A continuous process is especially advantageous from the point of view of process economics and thus of economic efficiency, as well as consistent quality. Within the scope of the invention, a continuous process should not exclude a semi-continuous process, which includes, for example, a batchwise operation. In this case, individual documents can be sprinkled with graphite salt, the graphite salt are expanded on the substrate to Graphitexpandatpartikeln and the Graphitexpandatpartikel be pressed on the individual documents each to a single graphite foil. Although in each case individual, discontinuous graphite foils are produced in this variant, the process as such can be carried out continuously in that the steps of sprinkling with graphite salt, expansion and compression take place continuously.

Preferably, the compressing step comprises a calendering step. This makes it possible to carry out a continuous process in a particularly advantageous manner by compressing the graphite expandate particles on the base or the underlay continuously between calendering rolls and graphite foil.

In an alternative semi-continuous process, graphite expandate is semi-continuously pressed onto the backing.

According to a further advantageous aspect of the invention, the pad is designed as a transport belt. This advantageously supports a continuous implementation of the method according to the invention.

The conveyor belt can preferably be formed as an endless belt, which is circumferentially guided, for example via deflection rollers, and in particular arranged and designed to be continuously drivable.

Preferred materials for the conveyor belt are, for example, metal, fiber materials containing, for example, metal or ceramic fibers, or other known temperature-resistant materials suitable for withstanding the expansion treatment associated with conventional heating devices, such as continuous ovens

Temperatures between 150 and 1000 ° C takes place, such as high temperature resistant plastics or CFRP materials. In this case, the acid which is used for the preparation of the graphite salt, can be selected specifically so that only a small increase in temperature for expanding treatment is necessary. Advantageously, organic acids, such as acetic acid, can be used. This allows the use of relatively temperature-sensitive materials for the conveyor belt, such as non-high temperature resistant plastics. Using common acids such as sulfuric acid or nitric acid, correspondingly higher temperatures are used for expansion, necessitating more temperature resistant materials for the conveyor belt. In the method according to the invention conventional types of heating can be used to expand the graphite salt. This can be advantageous

Convection heaters and / or radiators from the group consisting of infrared radiator, microwave radiator and laser, but also use induction heating. The heaters mentioned can be combined as needed.

According to a preferred embodiment of the method according to the invention, the graphite salt is applied to the substrate with a basis weight of less than 200 g / m ² , more preferably with a basis weight of less than 150 g / m ² , in particular less than 100 g / m ² , in particular from 50 g / m ² to 100 g / m ² . This makes it possible to produce especially thin graphite foils. With 10 to 40 wt .-% of volatile constituents in the graphite salt, which are expelled during expansion, such as stored sulfuric acid or organic acids such as acetic acid, with the surface weights of graphite salt mentioned a graphite foil with a basis weight of less than 120 up to 180 g / m ² , preferably less than 90 to 135 g / m ² , in particular less than 60 to 90 g / m ² , very particularly of between 30 to 45 g / m ² achieved, the smaller indication of the preferred upper limit of Basis weight (eg 30 g / m ² ) in each case for the use of organic acids and the larger (eg 45 g / m ² ) for the use of inorganic acids applies.

Compressing closes any intermediate spaces between the graphite expandate particles so that a graphite powder can be obtained from a monolayer of graphite salt particles even with the method according to the invention. let produce that has no or at least a few defects. This in turn is only possible because the graphite salt particles do not interlock with each other, as they would do in the expanded state, which ensures a uniform distribution on the substrate from the outset. This is particularly essential for very low basis weights of graphite salt particles on the substrate to a monolayer as the starting layer, in order to obtain a graphite foil of very small thickness, which has only a very small thickness variation. In a monolayer, a large variation in thickness would immediately lead to a variety of defects, such as holes.

However, a method according to the invention can also be advantageously used for the production of graphite foil, which despite the advantages of the method according to the invention has defects, in particular at extremely low basis weights. Such a graphite foil may be suitable for specific applications. Such applications in which a flat continuous graphite foil is not necessarily required, for example, a composite material of a plastic film and a graphite foil according to the invention. Due to a large number of defects even a net-like graphite foil can be created. The particle size of the graphite salt particles to be applied to the substrate is preferably less than 50 mesh, particularly preferably less than 80 mesh. Such small particles can be applied particularly evenly on the substrate. However, graphite salt particles with a particle size of 100 mesh and smaller may also be preferred if expansion methods are used which operate with heating elements of high energy density, such as lasers or induction heating elements, because their high energy input makes it possible to expand even with such small graphite salt particles. which is usually difficult to do otherwise

is impossible. Particularly preferably, the graphite salt is scattered onto the substrate and / or knife-coated. This is a particularly simple process step, which also leads to particularly homogeneous layers of graphite salt and thus to particularly homogeneous graphite films, in particular with respect to the local thickness and density. Advantageously, the graphite salt is applied by means of a powder scattering unit. The powder scattering unit may comprise an application brush, an applicator roll, a vibrating plate and / or a perforated plate, as well as all other known scattering devices suitable for the graphite salt particles. A combination of multiple scattering devices may allow for a multi-stage littering process by already scattering graphite salt particles evenly onto a second scattering device, such as a perforated plate, by a first spreading device, such as an applicator roll. The second scattering device further homogenizes the distribution of the graphite salt particles ultimately applied to the backing. For example, graphite salt particles can be scattered and / or geräkelt by a perforated plate.

The object of the invention is further achieved with a graphite foil according to claim 1 1, which is produced by the method according to the invention. Advantageous developments of the graphite foil according to the invention are given in the dependent claims 12 to 17.

The graphite foil according to the invention preferably has a weight per unit area of less than 150 g / m ² , particularly preferably less than 100 g / m ² , in particular less than 50 g / m ² , in particular between 30 and 50 g / m ² . These low basis weights can surprisingly be realized with the process according to the invention. They open up a large number of new applications for graphite foils, which, for example, enable the miniaturization of structures. Preferably, the graphite foil has a thickness between 10 μιτι and 150 μιτι, more preferably between 15 μιτι and 100 μιτι, in particular between 20 μιτι and 60 μιτι. This small thickness as well as the low basis weight is made possible by the method according to the invention. The correlation of the basis weight with the thickness of the graphite foil produced according to the invention is in particular the following: 100 g / m ² : 50-1000 μιτι, 50 g / m ² : 25-500 μηη, 30 g / m ² : 15-300 μηη. Preferably, the deviation from the average basis weight on 100 mm ² large faces less than 15%, more preferably less than 10%, most preferably less than 5%. Such low fluctuations of the average basis weight are possible by the method according to the invention. This means, for example, for a graphite foil having a basis weight of 40 g / m ^2, a deviation of less than 6 g / m ² , preferably less than 4 g / m ² , particularly preferably less than 2 g / m ² .

As an alternative, the graphite foil may form a laminate with at least one plastic film. As a result, a graphite foil according to the invention, in particular a very low basis weight and / or thickness, can be advantageously reinforced. However, self-supporting graphite foils can also be purposefully provided with additional properties by lamination with a plastic film, such as higher impermeability perpendicular to the film plane.

Advantageously, the plastic film of at least one of the plastics from the group comprising polyethylene terephthalate (PET), polyolefins such as polyethylene (PE) and polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyester, polyimide (PI), fluoroplastics, such as PVDF and PTFE, polycarbonate and biopolymers such as polylactide (PLA), cellulose acetate (CA) and starch blends. As PET in particular biaxially oriented polyester film is preferred, which also under the

Trade name Mylar® is known.

According to a first advantageous variant, the graphite foil and the plastic film are connected to each other by means of an adhesive. As the adhesive is preferably an adhesive from the group consisting of acrylates, polysiloxanes, polyurethanes, polyamides, acetates and epoxy resins in question.

According to a second advantageous variant, graphite foil and plastic foil are adhesively bonded together. This can be done for example by partial melting or sintering of the plastic film on the graphite foil (ie welding). Apart from supporting the graphite foil by the plastic film, for example, a leak perpendicular to the film plane can be prevented. For mechanical support alone, a perforated plastic film can also be advantageous. The perforation is, for example, evenly distributed over the plastic film and has, for example, an area ratio between 10 and 80%. The hole diameter may advantageously be between 0.25 and 2 mm, but depending on the use of the graphite foil, other hole diameters may also be advantageous.

A film according to the invention, in particular produced by a process according to the invention, can be used advantageously for a number of uses. The uses according to the invention are not exclusively, but preferably uses, which are made possible by the small thickness of the graphite foil according to the invention with high homogeneity. A first use according to the invention relates to the use in battery structures, such as heat dissipater and distributor and as a current collector in secondary batteries (ie rechargeable batteries), which is particularly space-saving formed with a small thickness of the graphite foil and the use of alternative

Electrolyte systems allows that can not or only partially be used in previously used collectors. Examples include the cathode side of a lithium-ion battery or the electrodes in EDLCs (electric double-layer capacitor, supercapacitors) in which aluminum-based current conductors can be advantageously replaced, or other applications in capacitor structures. The less graphite material is present, that is, the thinner the graphite foil, the more space remains for active material, which may be, for example, electrochemically active material, but also about phase change material for storing heat and / or cold. A possible large number of imperfections in extremely thin graphite foils can then be advantageously taken into account if - as in the case of current flow - missing graphite material hardly any influence on the desired properties - here the electrical conductivity within the

Graphitfolienebene - has or the amount of active material of the homogeneity of the film can be adjusted accordingly. Another use according to the invention is the use of the graphite foil according to the invention as resistance heating. This is particularly advantageous because with a small thickness of the graphite foil already at low currents, a strong heating occurs. Resistance heating can be used for conventional heaters such as hotplates, hot plates and the like. But it can also be provided with large-scale components, such as aircraft wings or rotor blades, which can be easily de-icing. Also, electric blankets can be provided with the graphite foil according to the invention as a resistance heating element. A small thickness of the graphite foil allows a low rigidity of the heating blanket.

Yet another use according to the invention is the use of graphite foil in gaskets. Here is a small thickness particularly advantageous because the

Volume leakage of a seal decreases in proportion to its thickness. Without losing the typical properties of a graphite foil, such as adaptability, compressibility and springback, as well as low creep behavior, the execution of a low thickness or low basis weight foil may result in loss of performance

Tightness in the plane can be improved. The particularly homogeneous thickness and density distribution of the graphite foil according to the invention allows the applications mentioned even with a small thickness of the graphite foil with very high quality and particularly low quality variations. A thin graphite foil as an outer layer in a multi-layered construction of a gasket with a metal reinforcement also acts as an anti-adhesion layer of the multi-layered structure when, for example, it is applied to the metal directly or another outer foil. Further advantageous embodiments and developments of the invention will be explained below with reference to a preferred embodiment and the accompanying figures.

Show

1 shows a schematic side view of an apparatus for carrying out the method according to the invention and Fig. 2: a schematic side view of a Aufrereuvorichtung for applying graphite salt on a transport pad.

In a method according to the invention (see Fig. 1), graphite salt 2 is scattered on a conveyor belt 1 as a base. GHS salt "SS3-low ash-PT" from AirWater Chemicals is used as graphite salt 2. The particle size of the individual graphite salt particles 3 in the present exemplary embodiment is 50 mesh, ie all graphite salt particles 3 can pass through a sieve of mesh size 300 μm 2 is scattered by means of a powder scattering unit 4. In this exemplary embodiment, the latter has a storage container 5, an application roller 6 and an application brush 7. Through an opening 8 in FIG

Feed tank 5 emerges graphite salt 2 from the feed tank 5 down and single Graphitsalzpartikel 3 come to lie in spaces 9 between individual teeth 10 of the applicator roll 6. With further rotation of the applicator roll 6, the graphite salt particles 3 fall on the conveyor belt. 1 The application brush 7 presses against the applicator roll 6 and on the one hand prevents the graphite salt particles 3 from falling out too early from the interspaces 9 and, on the other hand, promotes targeted removal of the graphite salt particles 3 from the interstices 9. Thus, the graphite salt particles 3 can be applied to the conveyor belt 1 in a targeted and very uniform manner become.

By a uniform feed rate (in Fig. 2 with an arrow 12) of the conveyor belt 1, which is ensured for example by a drive roller 1 1, in conjunction with the rotational speed of the applicator roll 6, the distance between the spaces 9, the rotational speed of the application brush. 7 and the particle size of the graphite salt particles 3 exactly a basis weight of the resulting layer 13 of graphite salt 2 can be adjusted. In the present embodiment, a basis weight of the graphite salt particles 3 of 75 g / m ^{2 is} set.

In a variant of the exemplary embodiment, as indicated in FIG. 1, a perforated plate 22 is arranged below the applicator roll 6, onto which the graphite salt particles 3 fall. len, and that - possibly in conjunction with a scraper (not shown) which presses the graphite salt particles 3 through the perforated plate 22 - allows an even more targeted application of graphite salt particles 3 on the conveyor belt 1. With the feed rate 12, the layer 13 is further transported and enters a heating zone 14, in which heating elements 15 are arranged. The heating elements 15 are in this example conventional radiant heaters, which are arranged over 2 m in length. The radiant heaters 15 heat the conveyor belt 1 at about 200 ° C from below. In addition, infrared radiators (not shown) are installed above the conveyor belt, which can generate temperatures of over 500 ° C. Due to the injected heat from above and below the graphite salt 2 is expanded, with sulfate as the intercalation compound gaseous sulfuric acid is formed, which expands the graphite salt by 300 to 400 times to graphite expandate 16. This is shown schematically in FIG. 1 as a continuously thickening layer 13, wherein the thickness profile does not run so uniformly in reality. In particular, when using graphite salt, which was prepared with organic acids, a heat input from above can be sufficient for the expansion of the graphite salt.

As heating elements 15 according to the invention microwave emitters, infrared radiators, circulating air heaters and similar heating elements, but also lasers, such as carbon dioxide laser, can be used and combined as needed and design of the entire system. The heating elements 15 can be arranged above and below the conveyor belt 1, wherein the thermal conductivity and other material properties of the conveyor belt, such as heat resistance, chemical resistance u. Ä. must be taken into account. For example, ceramic and stainless steel strips are suitable for inductive expansion.

As materials for the 60 cm wide conveyor belt 1 in this example, for example, metal bands in question, for example made of steel. Also, a high temperature-stable conveyor belt 1 of ceramic Nextel fibers from 3M preferred. For example, CFRP tape can also be used. The expansion sleeve is followed by a compression step in the feed direction. This is carried out continuously in this example as already the Aufrechudsritt and the expansion step. For this purpose, the layer 13 of graphite expander 16 passes through a calendering device 17 in a calendering step, which contains several calendering rolls 18. By a predetermined distance between the calendering rollers 18, the desired thickness of the resulting graphite foil 19 can be adjusted. Several calendering roller pairs 18 can be arranged one behind the other (not shown) in order to produce particularly thin graphite foils 19 in a particularly gentle manner.

In a further step, the graphite foil 19 is removed from the original tape 1 and rolled up. Alternatively, the graphite foil 19 can be integrated into the production process prior to rolling up or, after being rolled up, be densified in separate steps, laminated to plastic film, finished and / or impregnated. These and other suitable steps can advantageously be combined with each other, repeated, and tailored to each other.

The conveyor belt 1 is guided over a plurality of pulleys 20 back to the Aufrereuvorrichtung 4. Clamping devices 21 serve to adjust the tension of the transport belt 1 in a targeted manner.

The obtained graphite foil 19 has in the present embodiment

Basis weight of 62 g / m ² . The difference to the basis weight of the graphite salt particles 3 results from the removal of the volatiles during the expansion. The graphite foil 19 has no holes, which proves the homogeneity of the layer 13 of graphite salt 2 and the resulting graphite foil 19. The thickness of the graphite foil 19 is at 70 μιτι, the tensile strength is 2.8 MPa in the longitudinal direction, in the transverse direction 2.7 MPa. The bulk density is 0.9 g / cm ³ . In further exemplary embodiments, the thickness of the layer 13 and thus of the graphite foil 19 is varied by varying the parameters feed rate 12 and rotational speed of the application roller 6. Thus, for example, a Produce graphite foil with a thickness of 35 μιτι at a basis weight of 35 g / m ² .

The resulting graphite foil 19 is wound up at the end of the process and placed in a separate unit (not shown) with a Mylar® film under heat and pressure, i. by welding, laminated to a composite foil. Alternatively, a plastic film is adhered, for example with an acrylate resin as an adhesive, which is sprayed, for example, surface. All features mentioned in the description, examples and claims may contribute to the invention in any combination. In particular, various process parameters such as parameters of the spreading step, the expanding step and the compressing step, and various graphite salts can be advantageously combined with each other. Furthermore, graphite foil produced in such a way with specifically adjusted properties can in a targeted manner be combined with suitable plastic foils for special requirements.

Claims

claims

1 . A method of producing a graphite foil (19) from at least partially compressed graphite expander (16), comprising an expanding step of graphite salt (2) and a compressing step of the graphite expander (16) forming in the expanding step, characterized in that

in the expansion step graphite salt particles (3) on a support (1)

Graphitexpandat (16) are expanded, the Graphitexpandat (16) remains on the substrate (1) and is compressed in the compression step on the substrate (1) to the graphite foil (19).

2. The method according to claim 1, characterized in that the

Expansion step and / or the compression step are formed continuously.

A method according to claim 1 or 2, characterized in that the compressing step comprises a calendering step.

4. The method according to at least one of the preceding claims, characterized in that the base (1) is designed as a conveyor belt, in particular as a circulating endless belt.

5. The method according to at least one of the preceding claims, characterized in that the graphite salt (2) is applied with a basis weight of less than 200 g / m ² to the substrate, in particular with a basis weight of less than 150 g / m ² , in particular of less than 100 g / m ² , more particularly between 30 and 50 g / m ² .

6. The method according to at least one of the preceding claims, characterized in that the particle size of the graphite salt particles (3) is smaller than 50 mesh, in particular smaller than 80 mesh. Method according to at least one of the preceding claims, characterized in that the graphite salt (2) is sprinkled or spread on the base (1).

A method according to claim 7, characterized in that the graphite salt (2) is sprinkled or scrape over a Aufrereueinheit (4) on the substrate (1).

A method according to claim 8, characterized in that the

Aufrereueinheit (4) an order brush (7), an applicator roll (6), a

Rüttelblech and / or a perforated plate (1).

Method according to at least one of the preceding claims, characterized in that in the expansion step as at least one heater (15) for expansion of the graphite salt, a circulating air heater and / or a radiator from the group consisting of infrared radiator, microwave radiator and laser and / or an induction heating element or a combination is used from these.

Graphite foil produced by a process according to at least one of claims 1 to 10.

12. graphite foil according to claim 1 1, characterized in that they are a

Basis weight less than 150 g / m ² , in particular less than 100 g / m ² , in particular less than 50 g / m ² , in particular between 30 and 50 g / m ² has.

13. graphite foil according to claim 1 1 or 12, characterized in that it has a thickness between 10 μιτι and 150 μιτι, in particular between 15 μιτι and 100 μιτι, in particular between 20 μιτι and 60 μιτι.

14. graphite foil according to at least one of claims 1 1 to 13, characterized in that the deviation from the average basis weight to 100 mm ² large surface areas is less than 15%, in particular less than 10%, in particular less than 5%.

15 graphite foil according to at least one of claims 1 1 to 14, characterized in that it forms a laminate with at least one plastic film.

16. Graphite foil according to claim 15, characterized in that the

Plastic film of at least one of the plastics from the group

comprising polyethylene terephthalate (PET), in particular as a biaxially oriented polyester film, polyolefins, such as polyethylene (PE) and polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyester, polyimide (PI),

Fluoroplastics such as PVDF and PTFE, polycarbonate and biopolymers such as polylactide (PLA), cellulose acetate (CA) and starch blends.

17. graphite foil according to claim 15 or 16, characterized in that the plastic film is perforated.

18. Use of a graphite foil according to at least one of claims 1 to 17, in particular produced by a method according to at least one of claims 1 to 10, in battery structures, in capacitor structures, as a heat dissipater and distributor and / or as a current collector.

19. Use of a graphite foil according to at least one of claims 1 1 to 17, in particular produced by a method according to at least one of claims 1 to 10, as resistance heating for large-area components, such as aircraft wings or rotor blades, electric blankets and hot plates.

20. Use of a graphite foil according to at least one of claims 1 to 17, in particular produced by a method according to at least one of claims 1 to 10, as a seal or as an outer layer of a

Multi-layer construction of a seal.