Electrode film and method for its production

Description

[0001] The invention relates to an electrode foil which fulfills at least one predetermined function.

[0002] An electrode foil is to be understood as a foil-like functional material within the meaning of the invention and is always a composite material, i.e., a material made of three or more bonded materials, wherein at least one of these materials is a structural material and at least two of the materials are functional materials. The functional materials serve, in particular, to fulfill the function that is crucial and characteristic for the targeted, specific physical, chemical, physicochemical, biological, or other technical or technological application. As a whole, a foil-like functional material possesses different properties than the materials from which it is composed. It can therefore be used to realize a targeted function in a way that differs from how its individual materials could be used.

[0003] In materials science, functional materials are a subgroup of materials. Materials are generally divided into structural materials and functional materials. Unlike structural materials, functional materials are not primarily characterized by their mechanical strength and resulting mechanical stability, but rather by specific electrical, mechanical, magnetic, acoustic, optical, or biological-chemical properties that can be specifically influenced to modify the properties of a component. With functional materials, the focus is on the material's properties, intended use, and application, not on the structural design of components. Nevertheless, functional materials can also exhibit mechanical strength.

[0004] The invention relates to an electrode foil for use as an electrode in electrical energy storage devices, according to independent claim 1, and a method for producing this electrode foil, according to method claim 7. Independently of this, functional materials can also be realized on the basis of the present invention, which are described in dependent claims 2-6 and 8-12.

[0005] For the description of the invention, the term film-like material is used. Film-like materials generally possess many properties similar to films. However, they also exhibit some significant differences compared to them.

[0006] As is well known, films are thin materials in sheet or roll form, often made of plastic or metal, but also of other materials, with very little thickness and a large surface area. Typical film thicknesses are less than 0.4 millimeters. Films are generally manufactured in continuous rolls, wound up, and later often cut into pieces suitable for the respective application. Although films are characterized by large surface areas, they represent a three-dimensional solid, characterized by the fact that, if x and y characterize the surface area and z the thickness of the film, then Δx and Δy >> Δz, where Δx is the length, Δy is the width, and Δz is the thickness of the film.Another characteristic feature is that the material component, i.e., the material from which the film is made, completely fills the entire three-dimensional solid macroscopically. This means that there are no other materials or macroscopically free spaces within the solid. Only the material from which the film is made fills the three-dimensional space that the solid film encloses. All other materials that look like films, behave like films, and can be used like films, but which do not possess the aforementioned characteristics, are film-like materials. Unfortunately, it is often the case that these materials are also referred to as films, which, strictly speaking, is incorrect.

[0007] Foil-like materials, like films, are thin materials in sheet or roll form with a large extent in two dimensions and a comparatively small extent in a third dimension. Foil-like materials are also typically manufactured in continuous rolls, wound up, and often later cut into suitable pieces.The difference to films lies in the fact that the body of a film-like material, also characterized by x, y, and z, where x and y represent the surface area of ​​the body and z the direction of the cross-sectional extent of the film-like material (where the cross-sectional extent represents the measurable distance from one side of the body to the opposite side), and Δx the length, Δy the width, and Δz the cross-sectional extent of the film-like material, is permeated within these dimensions by a material that is continuous but does not completely fill the space. That is, the material from which the film-like material is composed does not completely fill the three-dimensional space spanned by this body in a macroscopic manner. Accordingly, this body is traversed by discrete or interconnected partial volumes, also called free volumes.Discrete subvolumes, also known as closed subvolumes, are cavities or voids that represent free space within certain boundaries. These boundaries are formed by the material from which the film-like material is made, the delimiting layer, or the structure.

[0008] A film-like functional material is a composition of interconnected materials. In a film-like functional material, the partial volumes surrounded or delimited by one material, for example, a structural material acting as a carrier medium, are permeated by one or more other materials or even completely filled by one or more materials other than the one delimiting the partial volumes, i.e., the carrier medium.

[0009] For this reason, the range of film-like functional materials is correspondingly large.

[0010] Expanded polytetrafluoroethylene, also known as ePTFE, a specially processed form of polytetrafluoroethylene, can be cited as an example of a structural material designed as a carrier medium. It can be in the form of a film-like material. During the processing, it is referred to as multidirectional ePTFE. The material produced by this manufacturing process is permeated with PTFE molecular fibers and is characterized by a porous structure with up to 70 percent open, fillable partial volumes.

[0011] Materials in the form of sheet-like textile structures, such as woven fabrics, knitted fabrics, braids, nonwovens, and felts, can also serve as carrier media for film-like materials. The main components of all textile products are textile fibers, i.e., fibers that can be processed in textile manufacturing processes, particularly those that can be spun. These are linear structures, meaning that the length-to-diameter ratio is significantly greater than 1, with sufficient length as well as flexibility and pliability as prerequisites for their processability. Based on their shape, fibers can be distinguished as staple fibers, meaning fibers of limited length, and filaments, meaning continuous fibers.

[0012] A distinct type of textile fabric is that constructed from metal wires. A textile woven from metal wire is called metal mesh or wire mesh. Metal mesh fabrics are also produced on looms.

[0013] For applications in electrical energy storage devices, electrode foils are used as positive or negative electrodes, or as anode or cathode foils, fulfilling both active and non-active functions. In the case of electrode foils, charge carrier storage in all its facets constitutes the active function. In contrast, non-active functions include electrical conductivity for the supply and removal of charge carriers, and the bonding function for the functional material that performs the active function. In the case of known electrode foils, the functional material often also contributes significantly to the mechanical stability of the electrode foil.

[0014] Electrical energy storage devices are based, for example, on the spontaneous conversion of chemical into electrical energy and are thus known as galvanic cells, or they are based on the storage of electrical energy in chemical compounds, where the reactants, as in redox flow batteries, are dissolved in a solvent. Alternatively, electrical energy storage devices can be based on the principle that energy is stored statically in an electric field. This principle is used particularly in capacitors, for example, in electrolytic capacitors, supercapacitors such as double-layer capacitors, pseudocapacitors, or hybrid capacitors. To achieve the highest possible energy storage capacity in a small form factor, the thickness of the electrode foil should be as small as possible.To ensure the mechanical stability of the electrode foils, construction materials in the form of carrier films or textile spatial surface structures are used.

[0015] Electrode foils often use metals in the form of metal foils as the material. Metal foils usually do not require any further metal coating or plating because, in addition to mechanical stability, the electrical conductivity for charge carrier supply and removal is ensured by the metal foil itself. In this context, the term stability encompasses the material's resistance to mechanical and thermal influences, such as mechanical and thermal stress, bending, strain, torsion, buckling, deformation, etc.

[0016] The z-dimension of these metal foils, i.e., their thickness, depends on the requirement that the necessary mechanical stability is met and the foil's further processing capabilities are ensured. Such metal foils cannot be manufactured arbitrarily thin to guarantee the required mechanical stability. However, considerably thinner metal foils would suffice to ensure electrical conductivity.

[0017] The mechanical stability of the film must enable the manufacturing process of the electrode films in the first place. Furthermore, the electrode film must ensure the functionality of the entire film component of the assembly. This requires sufficiently strong adhesion to the layers and components to be applied.

[0018] Electrode foils are also known, made from a dielectric material in foil form, for example, a polymer film with one- or two-sided metallization. The metallization must be designed and dimensioned to ensure the supply and removal of charge carriers. This includes sufficient electrical conductivity to withstand spontaneously occurring current densities. Since the thickness of these metal layers is usually above one or two micrometers, and the metal coating is applied chemically, electrochemically, or using vacuum technology, the production of this composite is correspondingly expensive compared to the manufacture of pure metal foils. A further disadvantage of two-sided metallization is that a dielectric is located between two independent metal layers. Additional process steps are required to connect these metal layers, i.e., to create a short circuit.

[0019] For the production of electrolytic capacitors, for example, electrically conductive aluminum foils are used as thin as possible. Electrically conductive foils made of high-purity aluminum with a foil thickness of less than 100 µm are difficult to process using conventional, state-of-the-art manufacturing processes, such as those used to produce anode foils for electrolytic capacitors, due to their insufficient mechanical stability.

[0020] In lithium-ion batteries, the thickness of conventional aluminum foils for the positive current collector, which must also ensure the electrode's mechanical stability, ranges between 25 µm and 15 µm. The aim here is to use foils with a thickness of approximately 10 µm. The thickness of conventional copper foils for the negative current collector in these batteries, which must also ensure the electrode's mechanical stability, ranges between 15 µm and 10 µm. The goal is to use foils with a thickness of approximately 6 µm. A major problem is the insufficient mechanical stability of the foils, especially during the electrode foil manufacturing process. Therefore, there are limits to reducing the foil thickness.

[0021] DE 10 2010 011 413 A1 discloses a cathodic electrode comprising a support made of a metallic material, in particular aluminum, with a thickness of 15 to 45 µm. EP 1 455 404 A2 describes an electrode unit with a porous support structure made of metal wire.

[0022] To improve the mechanical stability of a metal foil, a method for manufacturing a so-called GLARE component is known from DE 10 2012 000 508 A1. In this method, layers of aluminum and prepreg are alternately layered and subsequently bonded or pressed together. The layering is arranged such that aluminum layers are always on the outermost layer. Prepreg layers are understood to be pre-cured layers made of glass fiber-reinforced epoxy resin. However, mechanically stabilized metal foils produced using this method are not suitable for applications requiring a highly electrically conductive foil.

[0023] Fabrics coated with metal are also used in clothing. Maintaining the fabric's breathability is particularly important in this context. German patent DE 101 96 402 T1 describes a gold-laminated fabric and a method for its production. Breathability is ensured by the openings between the metal-coated carrier elements.

[0024] German patent application DE 10 2013 108 808 B4 discloses a method for producing a carbon-metal composite and a method for producing a semiconductor element assembly. A carbon fiber fabric with ribbon-shaped support elements is coated with a metal, making it suitable for heat dissipation from semiconductor devices. To fix the composite to the semiconductor devices, a solder metal is introduced into the spaces between the metal-coated carbon fiber fabric, structurally bonding the coated carbon fiber fabric to the semiconductor device. The first metal layer applied to the carbon fiber fabric thus primarily serves to dissipate heat from the device, while the subsequently introduced solder metal mainly fulfills the function of structurally fixing the composite to the device being cooled.The ribbon-like support elements fill a large portion of the total volume to ensure effective heat dissipation. The solder, on the other hand, occupies only a small fraction of the total volume, sufficient for attaching the heat sink to the semiconductor device. Consequently, the volume of the carbon fiber fabric constitutes a large part of the heat sink's total volume.

[0025] Further state of the art is disclosed in US 2009 / 311587 A1 and JPH10 321216 A.

[0026] The object of the invention is to provide an electrode foil comprising a support medium formed from a structural material, acting as a supporting base body, and at least two functional materials connected to the support medium. The support medium formed from the structural material should occupy only a small volume relative to the volume of the entire foil-like functional material, while maintaining sufficient mechanical stability for its use.

[0027] The problem is solved by an object and a method having the features according to independent claims 1 and 7. Further developments are specified in the dependent claims.

[0028] The problem is solved by an electrode foil that fulfills at least one predetermined function and can be used as a substrate in electrical energy storage devices. Within the foil-like functional material, a foil-like carrier medium, comprising a total carrier volume and consisting of at least one structural material, is arranged with a cross-sectional area ≤ 100 µm. This medium can be considered a matrix, i.e., a base body in which other materials are embedded. The carrier medium is formed from linear and node-shaped support elements, hereinafter referred to simply as linear and node-shaped support elements, which constitute the material components of the carrier medium and permeate the total carrier volume. These elements form a ribbon-like structure containing interconnected subvolumes of the total carrier volume, which are spanned by adjacent support elements.The linear and node-shaped support elements are coated with a first functional material that fulfills a first function, and the remaining volume of the total support volume formed by the interconnected partial volumes is filled with at least a second functional material that fulfills a second function that differs from the first function.

[0029] If the remaining volume of the total support volume formed by the interconnected partial volumes is filled with more than one second functional material, each second functional material fulfills at least one function that differs from the first function.

[0030] It is part of the invention that further functions can be fulfilled by the second or further functional materials introduced into the partial volumes. Furthermore, it should always be understood that the second or any further functional material introduced into the partial volumes does not necessarily fulfill only one function, but can fulfill several functions. In this context, at least one active or inactive function of a functional material introduced into the partial volumes differs from an active or inactive function of the first functional material encasing the support elements.

[0031] The support medium consists of a plurality of individual support elements, which are linear (large in one dimension) and small in the other two dimensions, and are node-shaped. Linear support elements, as defined in the invention, are support elements whose extent in the two dimensions where the linear support element is small is approximately equal. The ratio of the large dimension to the two smaller dimensions is at least 50:1. The ratio of the extents of the two smaller dimensions to each other is not less than 1:5 and not greater than 5:1. Linear support elements thus differ from ribbon-shaped support elements. In the case of at least partially large distances between the linear support elements, the illustrated limits of the linear support elements can also be exceeded.

[0032] The linear support elements are at least partially spaced far apart, such that their surface effect on the geometric plane in which the surfaces of the linear support elements lie is negligible, and thus the linear support elements do not provide a nearly complete separation of the spanned partial volumes from one another. Large spacing is defined as a distance between the individual linear support elements that is greater than 5:1 in relation to the larger of the two smaller dimensions of the linear support elements. In this case, the ratio of the two smaller dimensions can exceed the specified limitations.

[0033] A support element is considered node-shaped according to the invention if it has a similar extent in all dimensions; in particular, its extent in all dimensions is small compared to the large dimension of the linear support elements. When two or more linear support elements come into contact, the support medium exhibits node-shaped support elements at the points of contact.

[0034] In the context of the invention, the total carrier volume describes a volume that includes all carrier elements and thus the entire carrier medium.

[0035] According to the invention, a body has a ribbon-like extension if its extension in one dimension is small compared to the extension in the other two dimensions.

[0036] The support elements are coated with a first functional material. At the contact points of the support elements, the coating may have defects, provided that all areas of the coating are in contact with each other and form a continuous layer.

[0037] The support elements, which permeate the overall support volume, are arranged in sections spaced apart from one another such that partial volumes are spanned between adjacent support elements. These spanned partial volumes are designed as open, interconnected spaces. These partial volumes are not filled with support elements and thus form a gap between the support elements coated with a first functional material, which can be filled. According to the invention, these partial volumes, i.e., these gaps, are completely but not compactly filled with at least a second functional material.

[0038] In the following, the term "first functional material" will always refer to the functional material with which the linear and nodal support elements are coated, and the term "second functional material" will refer to the functional material that is introduced into, i.e., fills, the open, interconnected free volumes spanned by the support elements. The second functional material completely fills the open, interconnected free volumes spanned by the support elements, but not compactly. This means that the second functional material may contain smaller free volumes, for example, in the form of pores, which may be open and interconnected, as well as other secondary functional materials.

[0039] According to the invention, the support elements are encased in a first functional material which fulfills at least one first active or inactive function. The matrix shape of the coated, film-like support medium is retained. This means that the majority of the existing cavity, i.e., the free, interconnected partial volumes within the support medium, is also retained, but is reduced by the volume of the first functional material encasing the support elements. In particular, the total volume of the free partial volumes within the support medium is not less than the total volume of the support elements encased in the first functional material. Preferably, the ratio of the total volume of the free partial volumes to the total volume of the support elements encased in the first functional material is at least 2:1 or at least 5:1, and particularly preferably at least 10:1.

[0040] In an advantageous embodiment, when the linear support elements are arranged in parallel, the ratio of the extent of the linear support elements in the dimensions of the smaller extent to the distance between the linear support elements in the support medium is at least 1:1. The ratio is preferably at least 1:2 or at least 1:3 or at least 1:5.

[0041] Advantageously, one or more second functional materials can be incorporated into the existing partial volumes of the film-like functional material. These materials can fulfill active or non-active functions, and the upper and lower surfaces of the film-like functional material can be coated with a second functional material in an adhesive manner. At least one of these second functional materials fulfills at least one active or non-active function that differs from an active or non-active function fulfilled by the first functional material.

[0042] In particular, when the foil-like functional material is used as an electrode for electrical energy storage, open, pore-shaped, interconnected cavities are found within the second functional material or materials.

[0043] A foil-like functional material is therefore a composite material whose components or materials, in addition to the actual special function characteristic of the application of the functional material, perform one or more further functions in order to enable the intended application, such as storing electrical energy or catalytic processes or serving as a heating medium.

[0044] For this reason, it is usually necessary for the functional materials to fulfill both active and non-active functions.

[0045] Active function means that a functional material fulfills the function that corresponds to the purpose or intended use of the film-like functional material, i.e., is characteristic of the application of the film-like functional material.

[0046] A non-active function refers to the function of a functional material that is necessary to enable the active functions required for the intended use of the film-like functional material. For this reason, both active and non-active functions are extremely important. A functional material can fulfill one or more functions, which may be active or non-active.

[0047] In this context, the carrier medium or the construction material forming the carrier medium also fulfills a non-active function, namely the mechanical stability of the film-like functional material.

[0048] For the application of the film-like functional material, it may be advantageous for at least one second functional material to cover the top and / or bottom of the film-like functional material in an adhesive manner.

[0049] An advantageous configuration of the film-like functional material is one in which the linear support elements of the carrier medium form a fabric whose warp and weft threads, running perpendicular to each other, are interwoven. In a preferred embodiment, the warp and weft threads consist of several filaments. Alternatively, the warp and weft threads can be monofilaments.

[0050] In the formation of the foil-like functional material, the first functional material, i.e., the functional material with which the support elements are coated, is a metal.

[0051] In a preferred embodiment of the film-like functional material, the carrier medium is a fiberglass fabric tape, a carbon fiber fabric tape, a mineral wool fiber fabric tape, a polymer fiber fabric tape, or a wire mesh tape.

[0052] In a preferred embodiment of the film-like functional material, the second functional material contains one of the mixtures of substances from the group consisting of lithium / nickel oxide, lithium / manganese oxide, lithium / cobalt oxide and lithium / iron phosphate, as well as optionally further additives, preferably carbon black.

[0053] The problem can also be solved by a process for producing a film-like functional material. This process comprises the following steps: > Encasing of support elements of a carrier medium by applying a first functional material, which fulfills a first function, to the support elements and > filling the remaining volume of the total carrier volume formed by the interconnected partial volumes with at least a second functional material, which fulfills a second function that differs from the first function.

[0054] The encapsulation of the support elements can be achieved by metallizing the support elements.

[0055] Preferably, the metallization of the support elements of the carrier medium is carried out by physical vapor deposition of metal in a vacuum coating system. This physical vapor deposition of metal in a vacuum coating system is preferably performed by thermal evaporation, electron beam evaporation, laser beam evaporation, arc evaporation, cathode sputtering, or ion beam-assisted deposition processes.

[0056] Thermal vapor deposition, as defined in the invention, is a process in which a material is vaporized or atomized by means of the input of thermal energy and subsequently adheres to the support elements of the carrier medium. The application of several different deposition angles, i.e., more than two, during the thermal vapor deposition process is advantageous in order to coat the support elements as completely as possible, i.e., on all sides, with the first material.

[0057] Any other deposition methods mentioned here are adequate, differing essentially in the way energy is introduced into the first material.

[0058] In an advantageous embodiment of the process, the carrier elements are coated with the first functional material by thermal spraying. This thermal spraying is preferably carried out by wire flame spraying, powder flame spraying, high-speed flame spraying, high-speed wire flame spraying, arc wire spraying, plasma spraying, cold gas spraying, or melt bath spraying.

[0059] Even when using thermal spraying, the carrier elements of the carrier medium are completely enveloped on all sides with the first material at several different, i.e., more than two, spray angles.

[0060] As an alternative to thermal vapor deposition or thermal spraying at several different, i.e., more than two, deposition or spraying angles, thermal vapor deposition or thermal spraying for coating the support elements with the first functional material can be carried out by thermal vapor deposition or thermal spraying at one or two, preferably offset by 180°, deposition or spraying angles, combined with a subsequent heat treatment. During this heat treatment, heat is supplied to the first functional material, which has been applied to the support elements of the carrier medium by thermal vapor deposition or thermal spraying, for a defined short period or at defined time intervals, such that the deformability of the applied first functional material increases until it begins to flow and coat the support elements.The heat input must occur within such a time interval that the first functional material envelops the support element without dripping from it. This method can be applied to a cross-sectional expansion of the first material applied to the support elements of up to 10 µm.

[0061] Preferably, the heat input occurs in pulses with a pulse duration in the range of 1 ms to 100 s, whereby the temperature of the heat source is up to 500 K above the melting point of the applied first functional material. The effect of the heat input can therefore be considered a shock heating.

[0062] If the first functional material is electrically conductive and the thickness of the functional material layer applied to the support elements is less than one micrometer, heat can be applied using microwaves. In this process, the electrically conductive first functional material applied to the support elements is exposed to microwave radiation. The microwave energy is dimensioned such that the resulting heating alters the deformability of the first functional material, as already described, to such an extent that the support elements are encased in the first functional material.

[0063] For a layer of the applied first functional material up to approximately 1 µm thick, irradiation with a 2.45 GHz magnetron can be specified as follows: the irradiation power is in the range of 1 Ws / cm² to 10,000 Ws / cm² with an exposure time of 0.1 s to 150 s. To optimize heat input, the microwave irradiation power can also be supplied via pulse trains. The pulse widths range from 0.01 s to several seconds.

[0064] If the first functional material is a metal, metallization of the carrier elements of the carrier medium can be carried out by chemical metal coating in a two-stage process, in which the metallization of the carrier elements of the carrier medium comprises the following steps: ➢ Germination process and > Metal coating process.

[0065] Alternatively, the metallization of the support elements of the carrier medium can be carried out by electrochemical metal layer reinforcement in a three-stage process, wherein the metallization of the support elements of the carrier medium comprises the following steps: ➢ Germination process, ➢ Metal coating process and ➢ Metal layer reinforcement process.

[0066] In another possible variant, the metallization of the support elements of the carrier medium is carried out by immersing the carrier medium in a molten metal bath.

[0067] The application of the film-like functional material according to the invention lies in the formation of an electrode film for use in electrical energy storage devices. Strictly speaking, the term "electrode film" should not be used in this context, because the invention refers to a film-like electrode material. However, since the term "electrode film" is commonly used in practice for both films and film-like materials, it will also be used here, always with the caveat that the application according to the invention specifically involves a film-like electrode material.

[0068] The electrode foil conceptually consists of a foil-like functional material with a carrier medium, which acts as a matrix. The carrier elements of this medium are coated with a first electrically conductive functional material, preferably a metal such as aluminum, copper, silver, gold, brass, or other metals or metallic alloys. In special cases, other electrically conductive functional materials, such as conductive polymers, can also be used to form the electrically conductive layer surrounding the carrier elements. This electrically conductive functional material layer, with which the carrier elements of the carrier medium are coated, has the function of charge carrier transport, i.e., the transport of charge carriers into and out of the electrode foil. This is a non-active, but nevertheless important, function for an electrode foil.Since virtually all support elements of the carrier medium are interconnected, charge carrier inflow and outflow in the x, y, and z directions, and thus also current flow to the contacts of the electrode foil, is possible. The carrier medium metallized in this way, which can be considered a metallized matrix, has a thickness of ≤ 100 µm. Textile three-dimensional sheet structures with a cross-sectional area ≤ 100 µm are particularly proposed as the carrier medium. To form the electrode foil, it is further necessary to introduce a second functional material into the existing partial volumes in the carrier medium, which are defined by the metallized support elements. This second functional material fulfills at least one additional function. The second function fulfilled by the second functional material is energy storage.Charge carrier storage is an active function characteristic of an electrode foil used in an electrical energy storage device. It is also possible that the second functional material incorporated into the subvolumes fulfills additional functions beyond the aforementioned characteristic one. This could be a non-active function, such as electrical conductivity. The second functional material can also contribute to the mechanical stability of the electrode foil. Advantageously, the top and bottom surfaces of the electrode foil can be coated with the second functional material in a way that provides strong adhesion.

[0069] The invention provides a foil-like functional material in which the ratio of the functional material, which fulfills the active function characteristic for use as an electrode foil in an electrical energy storage device, to the other materials contained in the foil-like functional material, i.e. the construction material and the first functional material, is large.

[0070] A support medium made of a construction material designed as a textile surface element with three-dimensional dimensions can, according to the invention, be considered a matrix consisting of textile materials, particularly in the form of yarns or threads, but also of metal in the form of metallic threads, which are referred to as wires. Textile materials are defined as all materials that are manufactured or processed according to any textile technology. The yarns or threads, in turn, consist of individual elongated filaments, the monofilaments. Besides natural fibers, the material of the yarns or threads can include, for example, glass fibers, carbon fibers, mineral wool fibers, polymer fibers, or wires. Wires themselves constitute a monofilament. For the purposes of the invention, filaments also refer to fibers or wires.Yarns, threads, and wires can then be processed into a textile tape, in particular a woven tape in which individual warp and weft threads are interwoven. Such carrier materials can be, for example, woven, knitted, or crocheted fabrics.

[0071] For the application of a woven, knitted or crocheted fabric according to the invention, the thread density should be as low as possible, just as low as the technological processing requirements regarding the support and stability function still allow.

[0072] Coating the carrier elements of the carrier medium with the first functional material can lead to increased mechanical stability of the carrier medium, which can facilitate subsequent processing steps.

[0073] The processing of the carrier medium can be advantageously carried out using a roll-to-roll process.

[0074] Film-like functional materials can also be designed for other applications, in which case they are composites of different materials suitable for the respective application. For example, they can be designed for use in catalysts or in heated plastic mats with a micro-ventilation system, to name just two further examples.

[0075] Further details, features, and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. These show: Fig. 1: a basic schematic representation of a foil-like functional material in cross-section, Fig. 2A: a schematic representation of a matrix in its simplest structural form, Fig. 2B: a schematic representation of a matrix in a less disordered structural form than in Fig. 2A shown, Fig. 2C: Scanning electron microscope image of an expanded polytetrafluoroethylene film - ePTFE - as a matrix substrate for a film-like functional material. Fig. 2D: a schematic representation of a single-layer fabric as a carrier medium of a film-like functional material, Fig. 2E: a schematic representation of a single-layer knitted fabric as a form of a carrier medium for a film-like functional material, Fig. 2F: a scanning electron microscope image of a textile mesh as a form of a carrier medium for a film-like functional material, Fig. 3A: a basic schematic representation of a film-like functional material with a glass fabric in cross-section, Fig. 3B: a basic schematic representation of a cross-sectional view of an electrode foil according to the state of the art, Fig. 3C: a more detailed schematic representation of a foil-like functional material in cross-section, Fig. 4A: a schematic cross-sectional representation of the anode foil of an aluminum electrolytic capacitor with a glass fabric as a support medium, Fig. 4B: A scanning electron microscope image of a cross-sectional view of the anode foil of an aluminum electrolytic capacitor as a representative of a state-of-the-art functional foil. Fig. 5A: A scanning electron microscope image of a conventional electrode for lithium-ion batteries according to the state of the art in cross-section, Fig. 5B: A schematic cross-sectional representation of a foil-like electrode for lithium-ion batteries with a textile support medium, the support elements of which are encased in aluminum. Fig. 6 a schematic cross-section representation of a foil-like graphite electrode for lithium-ion batteries with a copper-plated steel wire mesh as a carrier medium,

[0076] The Fig. 1 Figure 1 shows the basic cross-sectional structure of a film-like functional material 1. The film-like functional material 1 has a matrix-shaped support medium 2 consisting of a construction material. The support elements 3 of this medium, which are designed as linear support elements 3a and node-shaped support elements 3b, are coated with a first functional material 4 that fulfills a first function. The support elements 3a and 3b define partial volumes 5, which are filled with a second functional material 6 that fulfills at least one second function that differs from the first.Depending on the application, the electrode foil 1 can also be referred to as foil-like electrode material 1 or as foil-like anode material 1 or as anode foil 1 or as foil-like cathode material 1 or as cathode foil 1, in which case the top and / or the bottom of the electrode foil 1 are completely covered with the second functional material 6.

[0077] In Fig. 2A Figure 1 schematically illustrates a simple, principal embodiment of a support medium 2. Linear support elements 3a and node-shaped support elements 3b are located only in mutually perpendicular planes. The support elements 3a and 3b span interconnected free partial volumes 5 that are open on all sides. The support medium 2 is film-like, meaning that its x and y dimensions are much larger than its z-direction dimension, which is referred to as the cross-sectional dimension 7 of the support medium 2. This condition always applies within the scope of this invention, even if the figures do not always clearly illustrate this. A support medium 2 is always composed of two different types of support elements 3a and 3b, which comprise all structural elements made of the construction material contained within the support medium 2.Linear support elements 3a are, for example, yarns in textiles or polymeric threads in expanded polymers, or linear structures, molecular fibers, spun fibers, textile fibers, filaments, or other linear structures. Nodular support elements 3b are, for example, crossed threads of warp and weft yarns in textile fabrics, intertwined threads, a compact concentration of thread-like elements of the construction material, a point-like accumulation of elements of the construction material, for example, in expanded polymers, three-dimensional clumps of the construction material, or similar. The support elements 3 span partial volumes 5 that are interconnected and open laterally and, in particular, towards the top and bottom of the support medium 2. In the specific case of the support medium 2 in . Fig. 2A The linear support elements 3a and the node-shaped support elements 3b are always located in parallel planes perpendicular to each other.

[0078] A medium is referred to as a support medium 2 when it has a three-dimensional extent. Therefore, it is considered a support medium 2 even if all support elements 3 lie in a plane, but this plane no longer represents a two-dimensional surface, but rather has a three-dimensional extent.

[0079] In Fig. 2B is a schematic representation of a more disordered arrangement of a carrier medium 2 compared to the carrier medium 2 made of Fig. 2A , as one of the more typical forms of a carrier medium 2 for a film-like functional material. This schematic representation is intended to show that it is not absolutely necessary for a carrier medium 2 to have an ordered structure. The distribution of the linear carrier elements 3a and the node-shaped carrier elements 3b can certainly be disordered. Even in the case of the Fig. 2B The support elements 3a and 3b span interconnected and open-sided free partial volumes 5.

[0080] In Fig. 2C Figure 1 shows a scanning electron microscope image, hereinafter referred to as SEM image, in a top view of an expanded polytetrafluoroethylene film, called ePTFE, as a support medium 2. Linear support elements 3a and nodular support elements 3b are disordered. The linear support elements 3a are oriented molecular fibers, and the nodular support elements 3b represent point-like accumulations of polytetrafluoroethylene material components. The oriented molecular fibers, i.e., the linear support elements 3a and the nodular support elements 3b, span partial volumes 5. The partial volumes 5 are interconnected.

[0081] In Fig. 2D A carrier medium 2 in the form of a textile fabric is schematically represented. The linear carrier elements 3a are yarns, threads, or wires, which are referred to as warp threads and weft threads. The knot-shaped carrier elements 3b are the areas where warp threads and weft threads intersect. The carrier medium 2, designed as a textile fabric, in Fig. 2D This is an example of how all support elements 3 lie virtually in one plane, yet the support medium 2 has a three-dimensional extent. Open partial volumes 5 are spanned between the linear support elements 3a, the warp threads and the weft threads, and their intersection points, the knot-like support elements 3b. The distance resulting from the crossing of warp and weft threads corresponds to the cross-sectional area 7 of the support medium 2.

[0082] In Fig. 2E Figure 1 is a schematic representation of a top view of a knitted textile as a carrier medium 2. Such film-like textile structures can be industrially produced from yarn systems by knitting on a knitting machine; they belong to the category of knitted fabrics. The linear carrier elements 3a are, in this case, textile yarns, while the knot-shaped carrier elements 3b are formed by intertwined yarns. Open partial volumes 5 are stretched between the linear carrier elements 3a, which are formed by textile yarns, and their intertwined, overlapping portions of the textile yarns, the knot-shaped carrier elements 3b. The distance resulting from the intertwined, overlapping portions of the textile yarns corresponds to the cross-sectional area 7 of the carrier medium 2.

[0083] In Fig. 2F The image shows a SEM image of a top view of a mesh as a support medium 2. The linear support elements 3a are formed by textile threads, and the knot-like support elements 3b are formed by intersections or clusters of textile threads. In this example, the distribution of the linear support elements 3a and the knot-like support elements 3b is stochastic. Open partial volumes 5 are spanned between several intersecting textile threads, the knot-like support elements 3b, and a relatively large number of textile threads, the linear support elements 3a.

[0084] In Fig. 3A Figure 1 schematically depicts a film-like functional material 1, consisting of a textile carrier medium 2, shown in cross-section. The linear carrier elements 3a, the textile warp and weft threads and their intersection areas, the knot-like carrier elements 3b of the textile carrier medium 2, a textile fabric, are enveloped by a first functional material 4, which fulfills a first function. The partial volumes 5 are filled with a second functional material 6, which fulfills at least a second function that differs from the first. The top and bottom surfaces of the carrier medium 2 are covered with the second functional material 6. The carrier medium 2 is a glass fabric, the basic structure of which is shown in Figure 2. Fig. 2D As shown, a first functional material 4, which fulfills a first function, is applied to both the linear support elements 3a and the nodal support elements 3b. The first functional material 4 envelops the linear and nodal support elements 3a and 3b. DA denotes the cross-sectional area 7 of the support medium 2, whose support elements 3 are enveloped by the first functional material 4.

[0085] D VfFM denotes the thickness of the foil-like functional material 1, the top and bottom of which are coated with the second functional material 6.

[0086] Fig. 3B shows as a comparison to the one in Fig. 3A The foil-like functional material 1 shown is a conventional electrode foil according to the prior art with a metal foil 2' or a metallized foil, preferably a metallized polymer foil, as the carrier medium 2', in cross-section. The same functional material 6 is applied to both sides of the carrier medium 2', with which the open partial volumes 5 of the foil-like functional material 1 are formed according to Fig. 3A The material was applied after the surface had been filled and the top and bottom surfaces had been coated with an adhesive layer. Here, DTF corresponds to the thickness of the metal foil 2', which acts both as a carrier medium and fulfills the function of charge carrier supply and removal. DVF corresponds to the thickness of the electrode foil. The thickness DVF of the electrode foil is made of... Fig. 3B corresponds to the thickness D VfFM of the foil-like functional material 1 coated on both sides with the second functional material 6. Fig. 3A , which is denoted by D VfFM. Therefore, D VfFM = D VF .

[0087] Fig. 3C The cross-section shows a detailed schematic representation of the in Fig. 3A The shown film-like functional material 1. The second functional material 6 fulfills at least one active and at least one inactive function. The second functional material 6 has an internal structure of open pores 8, which, however, do not correspond to the partial volumes 5.

[0088] In principle, the film-like functional material 1 according to the invention is characterized by a large volume or mass fraction of the second functional material 6 relative to the total volume or mass of the film-like functional material 1. This is crucial for the application of the film-like functional material 1 because it ensures that a large proportion of the total volume or mass of the film-like functional material 1 is occupied by the second functional material 6, which fulfills an active function.

[0089] In Fig. 4A The diagram shows a cross-section of an anode foil 1 for an aluminum electrolytic capacitor, i.e., a foil-like functional material 1 in an application as an electrode, where the support medium 2 is a glass fabric, as in Fig. 2D The support elements 3 are coated with aluminum as the first functional material 4. The layer thickness can range from 0.2 µm to 4 µm, depending on the electrode type. Highly porous aluminum is introduced into the partial volumes 5 as the second functional material 6. The highly porous aluminum is also located on the top and bottom surfaces of the support medium 2. In the right part of the Fig. 4A The enlarged section shown reveals that the highly porous aluminum consists of a highly porous aluminum body 9 and aluminum oxide layers 10 that have formed on the surfaces of the highly porous aluminum body 9, as well as open pores 8. When the foil-like functional material 1 is used as an electrode for an electrical energy storage device, the open pores 8 in the second functional material 6 serve to hold an electrolyte. The aluminum oxide layer 10 is produced on the surface of the highly porous aluminum body 9 by anodic oxidation and forms the dielectric layer of the aluminum electrolytic capacitor. The highly porous aluminum body fulfills a non-active function, namely the transport of charge carriers.The aluminum oxide layer 10 fulfills the active function of charge carrier storage, i.e., charge carrier storage as a characteristic function of the application of the foil-like functional material 1 as an anode foil 1 for an aluminum electrolytic capacitor. The open pores 8 are filled with electrolyte. In this sense, they fulfill a non-active function by providing the volume for the electrolyte. The introduction of the highly porous aluminum into the partial volumes 5 and its application to the top and bottom surfaces of the support medium 2 is preferably carried out by vacuum coating processes.

[0090] The amount of aluminum, as the first functional material 4, which encases the support elements 3, must be of a dimension that meets the electrical conductivity requirements. This typically corresponds to an aluminum layer with a thickness between 0.2 µm and 4 µm. To ensure these requirements, a glass fabric with twenty-two warp and weft threads per centimeter is used, for example, as the support medium 2. The fabric is flattened. Through compression, warp and weft threads with a width of 180 µm and a thread height of 15.5 µm are created. The first functional material 4, in the form of an aluminum layer, which is characterized by excellent electrical conductivity properties, is applied to these threads.The carrier medium is thus metallized with the first functional material 4, namely aluminum, with the average layer thickness of the aluminum applied to the warp and weft threads being approximately 2.5 µm. This results in a cross-sectional area 7 of 36 µm for the metallized carrier medium 2. Highly porous aluminum was deposited as the second functional material 6 into the partial volumes 5 of the metallized carrier medium 2, i.e., in the mesh spaces of the glass fabric. Highly porous aluminum, each with a layer thickness of 32 µm, was also deposited onto the top and bottom surfaces of the foil-like functional material 1. The total thickness of the anode foil 1 is 100 µm.

[0091] The carrier medium 2, metallized with aluminum as the first functional material 4, occupies a volume of 0.00156 cm³ per square centimeter of the base area of ​​the anode foil 1. The total volume of the anode foil 1 per square centimeter of base area is 0.01 cm³. Thus, the volume fraction of the carrier medium 2 and the first functional material is approximately 15.6%, while the volume fraction of the second functional material 6, namely the highly porous aluminum, is approximately 84.4%.

[0092] In contrast, in a conventional anode foil 1', the support medium 2' occupies a considerably larger proportion of the total volume of the anode foil 1'. One possible embodiment of such a conventional anode foil 1' according to the prior art is described in Fig. 4B The cross-sectional view shows this anode foil 1'. It is made from a high-purity aluminum foil by electrochemical etching, with the inner portion remaining unprocessed. This portion constitutes the support medium 2' of the anode foil 1'. A conventional anode foil 1' with a thickness of 100 µm, as shown in the SEM image, Fig. 4B As shown, the thickness of the support medium 2', which was not electrochemically etched, is approximately 28.6 µm, and the electrochemically etched area is approximately 71.4 µm, corresponding to a thickness of approximately 35.7 µm per side for this area. After a so-called forming process, an electrochemical or anodic oxidation, the anode foil 1' is formed. The support medium 2' acts as the carrier and is simultaneously responsible for the supply and removal of charge carriers. The electrochemically etched area performs the actual capacitor function, i.e., the storage of charge carriers. It can be estimated that the ratio of the thickness DTF between the support medium 2' and the layer performing the actual capacitor function is approximately 1 to 2.5, or 1 to 2.5.

[0093] The carrier medium 2' of the conventional anode foil 1' occupies a volume of 0.00286 cm³ per square centimeter. This corresponds to approximately 28.6% of the total volume of the conventional anode foil 1' according to the prior art. The area of ​​the conventional anode foil 1' that performs the capacitor function occupies a volume of 0.0032 cm³ per square centimeter of base area. This corresponds to approximately 71.4% of the total volume. In contrast, in the solution according to the invention, 84.4% of the total volume is available for performing the capacitor function, i.e., for storing charge carriers.

[0094] In the case of the anode foil 1 for an aluminum electrolytic capacitor, the proportion of the volume available for the second functional material 6 to fulfill the capacitor function can be further increased to up to 94%, for example by further reducing the number of warp and weft yarns or by using yarns with filaments having a diameter of 4 µm instead of yarns with filaments having a diameter of 5 µm.

[0095] In Fig. 5A This is a cross-sectional SEM image of the cathode 1' of a state-of-the-art lithium-ion cell. The term cathode here always refers to the cell's discharge point. The electrode belongs to the class of lithium metal oxide electrodes. Such a conventional cathode 1' consists of an intrinsically poorly conductive active material, such as lithium and nickel oxide, lithium and manganese oxide, lithium and cobalt oxide, or lithium and iron phosphate, as well as a number of additives that serve as functional materials fulfilling non-active functions. Carbon black is an important additive for achieving electrical conductivity. An aluminum foil serves as the substrate 2'.

[0096] The anode of a lithium-ion battery, which is not shown here, consists of graphite and is therefore also called a graphite electrode. The support medium 2' for the cathode, which is also called a current collector, is an aluminum foil 2', and for the anode (not shown) a copper foil. This is also the case in the application shown in Fig. 5A The support medium 2' is an aluminum foil with a thickness of 30 µm. The use of such an aluminum foil is considered prior art. Furthermore, prior art solutions exist in which the support medium 2' is an aluminum foil with a thickness of 15 µm. The aim is to use 10 µm thick aluminum foils as the support medium 2'. The total thickness of the cathode foil is approximately 194 µm.

[0097] In Fig. 5B The cross-sectional view schematically shows the application of a film-like functional material 1 as the cathode 1 of a lithium-ion cell. The film-like functional material 1 has a three-dimensional textile structure as a carrier medium 2 in the form of a glass fabric with 18 warp threads and 18 weft threads per centimeter. The linear carrier elements 3a (warp and weft) have an approximately circular cross-section with a diameter of about 35 µm. The areas where the warp and weft threads intersect form the knot-like carrier elements 3b. Aluminum, as the first functional material 4, is applied to the carrier elements 3a and 3b. The thickness of the applied aluminum layer is approximately 7 µm. The partial volumes 5 of the metallized carrier medium 2, i.e., the mesh spaces 5 between the warp and weft threads, are filled with the second functional material 6.The top and bottom surfaces of the film-like functional material 1 are each additionally coated with the second functional material 6 to a thickness of 55 µm. The second functional material 6 consists of a mixture of lithium iron phosphate, conductive carbon black, solvent, binder, and additives. The novel cathode 1 was calendered. Calendering, in this context, means that the film-like functional material 1 is successively passed through the gaps between several successively arranged heated and polished rollers, resulting in compaction and hardening of the film-like functional material 1, i.e., the cathode 1. After these processes, the thickness DVfFM of the cathodes 1 is 194 µm, making it comparable to that in [reference missing]. Fig. 5A The solution presented is easily achievable using state-of-the-art technology.

[0098] The carrier medium 2' in the form of an aluminum foil which is in Fig. 5 A The cathode 1' shown, according to the prior art, has a volume of 0.003 cm³ per square centimeter. This corresponds to approximately 15.5% of the total volume of the cathode 1'. The second functional material 6, applied to both sides of the support medium 2', occupies a volume of 0.0164 cm³ per square centimeter of base area. This corresponds to approximately 84.5% of the total volume.

[0099] Using a 15 µm thick aluminum foil as the support medium 2', the volume of the second functional material 6 would be approximately 0.018 cm³. This would correspond to about 92.3% of the total volume of the cathode 1'. Using a 10 µm thick aluminum foil as the support medium 2', the volume of the second functional material 6 would be approximately 0.0184 cm³. This would correspond to about 94.85% of the total volume of the cathode 1'.

[0100] At the in Fig. 5B In the illustrated solution of a cathode 1 using a film-like functional material, the volume of the support medium 2, whose support elements 3 are coated with the first functional material 4, occupies approximately 4.7% of the total volume of the cathode 1. Thus, the volume fraction of the second functional material 6 is approximately 95.3% of the total volume of the cathode 1. In comparison, in a Fig. 5A In the solution shown from the prior art, even when using a 10 µm thick aluminum foil as the carrier medium 2', which is not yet technically feasible, only a proportion of the second functional material 6 of the total volume of the cathode 1' of a maximum of 94.85% is possible.

[0101] In Fig. 6 The diagram schematically shows a cross-sectional view of the anode 1 of a lithium-ion cell using a foil-like functional material. The anode 1 has a steel wire mesh as a support medium 2 with twenty warp wires and twenty weft wires per centimeter. The warp and weft wires are therefore monofilaments and have a diameter of approximately 15 µm. A compact copper layer approximately 4 µm thick is applied as the first functional material 4 to the support elements 3 (wires as linear support elements 3a and their intersections as node-like support elements 3b). The partial volumes 5 spanned by the support elements 3 are filled with the second functional material 6. The top and bottom surfaces of the foil-like functional material 1 are each coated with the second functional material 6 to a thickness of 75 µm. The second functional material is open-pore graphite.Anode 1 was calendered, as is standard practice. The thickness D VfFM of anode 1 after calendering is 188 µm.

[0102] One of the in Fig. 6 The anode shown in Figure 1, comparable to a state-of-the-art lithium-ion battery, consists of graphite bonded to a copper foil. Using a 15 µm thick copper foil, this occupies a volume of 0.0015 cm³ per square centimeter of anode base area. This corresponds to approximately 8.0% of the total volume of the anode. The graphite bonded to the copper foil, i.e., the second functional material 6, occupies a volume of 0.0173 cm³ per square centimeter of anode base area. This corresponds to approximately 92.0% of the total volume of the anode. Using a 6 µm thick copper foil, this occupies a volume of 0.0006 cm³ per square centimeter of anode base area. This corresponds to approximately 3.2% of the total volume of the anode.The graphite, the second functional material 6, which is firmly adhered to the copper foil, occupies a volume of 0.0182 cm³ per square centimeter of anode base area. This corresponds to approximately 96.8% of the total volume of the anode.

[0103] In comparison, the in Fig. 6 In the solution shown, the support medium 2, whose support elements 3 are coated with a compact copper layer approximately 4 µm thick, occupies a volume of approximately 0.0002 cm³ per square centimeter of anode base area, which is about 1.1% of the total volume of the anode. The second functional material 6, graphite, occupies a volume of approximately 0.0186 cm³ per square centimeter of anode base area. Thus, the proportion of the second functional material 6 to the total volume of the anode 1 is 98.9%.

[0104] The production of a cathode 1 or anode 1 according to the invention using a film-like functional material can be carried out as follows: A textile fabric is used as the carrier medium 2. The carrier elements 3, i.e., warp and weft as linear carrier elements 3a and the intersection area of ​​warp and weft as knot-like carrier elements 3b, are coated with an electrically conductive metal suitable for the intended use, for example, aluminum or copper, as the first functional material 4, in an adhesively encasing manner. The layer thickness is between 1 µm and 4 µm. In the understanding of the invention, the carrier medium 2 serves to provide mechanical stability to the film-like functional material 1, and the first functional material 4 fulfills the non-active function of charge carrier supply and removal. However, the first functional material 4 can also contribute to increasing the mechanical stability of the film-like functional material 1.

[0105] The coating of the support elements 3 with the first functional material 4 can be achieved using vacuum-assisted PVD processes or thermal spraying processes, in which, depending on the process, a thermal post-treatment as already described may be necessary, by the chemical and electrochemical processes described, or by immersion of the support medium in a molten metal bath, whereby the melting temperature of the metal must be below the temperature that would lead to the destruction of the textile fabric. Subsequently, the partial volumes 5 enclosed by the support elements 3, which are coated with the first functional material 4, are filled with the second functional material 6. This creates a film-like functional material 1, which is then further processed into a cathode 1 or anode 1 using methods known from the prior art.

[0106] To produce a cathode 1 or anode 1, the top and bottom surfaces of the foil-like functional material 1 are coated with the second functional material 6. The second functional material 6 is, for example, a coating compound known from the prior art – called slurry. The second functional material fulfills the active function of charge carrier storage and the non-active function of charge carrier supply and removal to the storage locations in the second functional material 6. It can also contribute to mechanical stabilization. The coating compound is contained in a reservoir where the components can also be mixed, and is applied to both sides of the foil-like functional material 1 by an application system, i.e., an application tool.

[0107] The processes following the coating, such as drying, can be carried out according to the state of the art.

[0108] A textile fabric suitable as a carrier medium 2 for a film-like functional material 1 according to the invention should not necessarily be characterized by a high density of warp and weft threads, but sufficiently large partial volumes 5 should be stretched by the warp and weft threads as linear carrier elements 3a and their intersection points as knot-shaped carrier elements 3b, provided, however, that the mechanical stability of the textile fabric is sufficiently high for the carrier function.

[0109] This means that a textile fabric suitable as a carrier medium 2 does not necessarily have to be characterized by a particularly small cross-sectional area 7 or a particularly small mesh size.

[0110] However, in many cases it is advantageous to keep the diameter of the filaments from which yarns for warp and weft threads for a carrier medium 2 are made as small as possible in order to keep the volume fraction of the carrier medium 2 in relation to the total volume of the film-like functional material 1 sufficiently small, provided, of course, that the mechanical stability of the textile fabric is sufficiently high for the carrier function.

[0111] The following describes an anode foil for an aluminum electrolytic capacitor: The anode foil has a thickness of 100 µm. The substrate 2 is a glass fabric (EC5 5.5 1x0 5 5.5 1x0). This glass fabric has a thread density of 22 warp threads and 22 weft threads per cm. The warp and weft threads each consist of filaments with a diameter of 5 µm, a thread width of 160 µm, and a thread height of 17.5 µm. A 2.5 µm thick aluminum layer is applied to the warp and weft threads as the first functional material 4. The metallized glass fabric is characterized by the following geometric properties: ➢ The cross-sectional area 7 of the metallized fabric is 0.004 cm, or 40 µm. ➢ The mesh size of the metallized glass fabric is approximately 0.031 cm x 0.031 cm. ➢ The metallized glass fabric has a volume of approximately 0.004 cm³ per cm² of glass fabric surface area. ➢ The metallized glass fabric occupies approximately 38.36% of the volume of the film-like functional material 1; the sum of the open, interconnected partial volumes 5 spanned by the linear and node-shaped support elements comprises 61.64% of this volume of the film-like functional material 1.

[0112] The partial volumes 5 are filled with highly porous aluminum as a second functional material 6. This creates a foil-like functional material 1. To form the anode foil, the top and bottom surfaces of the foil-like functional material 1 are also coated with highly porous aluminum. The anode foil 1 produced in this way is characterized by the following geometric dimensions: ➢ The sum of the volumes of the highly porous aluminum applied to the top and bottom surfaces of the foil-like functional material 1, i.e., the second functional material, is 0.006 cm³ per square centimeter of anode foil base area. ➢ The total volume of the highly porous aluminum, i.e., the second functional material, which fulfills the charge carrier storage function characteristic of an electrolytic capacitor, is 0.0085 cm³ per square centimeter of anode foil base area. ➢ The highly porous aluminum occupies 85% of the total volume of the anode foil.

[0113] In another anode foil for an aluminum electrolytic capacitor, a glass fabric with a warp and weft yarn consisting of approximately 102 filaments with a diameter of 5 µm and a thread density of 15 to 20 threads per cm² is used as the support medium 2. Compression of the thread cross-section and smoothing of the thread curvature under biaxial tension achieves a significant reduction in the cross-sectional area 7. This can range from 25 µm to 35 µm, with the mesh size within a range of 325 µm to 550 µm x 325 µm to 550 µm. In this anode foil, the proportion of the volume of the foil-like functional material 1 occupied by the metallized glass fabric, the metallized support medium 2, can be reduced to 13.5%.

[0114] In another anode foil for an aluminum electrolytic capacitor, a glass fabric with a warp and weft yarn consisting of approximately 51 filaments with a diameter of 4 µm and a thread density of 20 to 25 threads per cm² is used as the carrier medium 2. Compression of the thread cross-section and smoothing of the thread curvature under biaxial tension achieves a significant reduction in the cross-sectional area 7. This can range from 10 µm to 18 µm, with the mesh size within a range of 300 µm to 425 µm x 300 µm to 425 µm. In this anode foil, the proportion of the volume of the foil-like functional material 1 occupied by the metallized glass fabric, the metallized carrier medium 2, can be reduced to 5.5%.

[0115] The following describes a positive or negative electrode for lithium-ion batteries: A textile fabric with a warp and weft yarn consisting of approximately 102 filaments with a diameter of 5 µm and a thread density between 12 and 18 threads per cm² is used as the carrier medium 2. The cross-sectional area 7 of the carrier medium 2 can be up to 100 µm. The mesh size can be within the range of 400 µm to 725 µm x 400 µm to 725 µm. The support elements 3 of the carrier medium 2, i.e. warp and weft as linear support elements 3a and intersection area of ​​warp and weft as node-shaped support elements 3b, are coated with an electrically conductive metal, aluminium or copper, corresponding to the intended use, positive or negative electrode, as the first functional material 4, in an adhesively enveloping manner.The proportion of the volume occupied by the metallized support elements 3 is approximately 6% of the total volume spanned by the support medium 2.

[0116] Using yarns consisting of 51 filaments with a diameter of 4 µm and an almost circular cross-section, support media 2 can be produced from textile fabrics with a thread density of between 17 and 22 threads per centimeter and a cross-sectional area 7 of up to 65 µm. The mesh size is within the range of 425 µm to 600 µm x 425 µm to 600 µm. The proportion of the volume occupied by the metallized support elements 3 is then approximately 3% of the total volume spanned by the support medium 2. Bezugszeichenliste

[0117] 1 Foil-like functional material, foil-like anode material or anode foil, foil-like cathode material or cathode foil 1' Conventional electrode foil from the prior art, anode or cathode from the prior art, foil-like functional material from the prior art, anode foil for electrolytic capacitors from the prior art, 2 Carrier medium 2' Carrier medium in the prior art; metal carrier foil, metallized polymer foil, aluminum foil in the prior art 3 Carrier element 3 Linear carrier element 3b Nodular carrier element 4 First functional material, first functional material 5 Partial volumes, mesh space of a fabric 6 Second functional material; second functional material 7 Cross-sectional extent of the carrier medium 2 8 Open pores 9 Aluminum body 10 Aluminum oxide layers DA cross-sectional area of ​​the carrier medium 2 D VfFM thickness of the coated film-like functional material 1 D TF thickness of the carrier film 2' D TF thickness of the electrode film

Claims

1. Electrode film (1) for use in electrical energy storage devices containing a film-like carrier medium (2) which consists of at least one structural material, comprises a carrier overall volume, has a cross-sectional extent (7) ≤ 100 µm, can be regarded as a matrix and consists of linear carrier elements (3a) which are large in one dimension, the large dimension, and small in the two other dimensions, the two smaller dimensions, wherein the ratio of the large dimension to the two smaller dimensions is at least 50:1 and the ratio of the two smaller dimensions to one another is not smaller than 1:5 and not greater than 5:1, and nodular carrier elements (3b) which form the material components of the carrier medium (2) and pass through the carrier overall volume, so as to form a strip-like extent containing interconnected partial volumes (5) of the carrier overall volume which are spanned by carrier elements (3) which are in proximity to one another, wherein some of the linear carrier elements (3a) have large spacings from one another which in relation to the larger of the two smaller dimensions of the linear carrier elements (3a) are greater than 5:1, wherein the linear carrier elements (3a) and the nodular carrier elements (3b) are coated with a sheath of a first functional material (4) which performs a first function, and wherein the remaining volume, formed by the interconnected partial volumes (5), of the carrier overall volume are completely but not compactly filled with at least one second functional material (6), which performs a second function different from the first function.

2. Electrode film (1) according to Claim 1, characterized in that at least one second functional material (6) covers the top side and / or the bottom side of the carrier medium (2).

3. Electrode film (1) according to one of Claims 1 and 2, characterized in that the linear carrier elements (3a) of the carrier medium (2) are interwoven warp and weft threads which extend perpendicularly in relation to one another and form a woven material.

4. Electrode film (1) according to one of Claims 1 to 3, characterized in that the first functional material (4) is a metal.

5. Electrode film (1) according to one of Claims 1 to 4, characterized in that the carrier medium (2) is a woven glass-fibre strip or a woven carbon-fibre strip or a woven polymer-fibre strip or a woven wire strip.

6. Electrode film (1) according to one of Claims 1 to 5, characterized in that at least one second functional material (6) contains one of the mixtures of substances from the following group: lithium / nickel oxide, lithium / manganese oxide, lithium / cobalt oxide and lithium / iron phosphate, and possibly also further additives, preferably carbon black.

7. Method for producing an electrode film (1) according to one of Claims 1 to 6, comprising the following steps: ➢ sheathing carrier elements (3) of a carrier medium (2) by applying a first functional material (4), which performs a first function, to the carrier elements (3) and ➢ filling the remaining volume, formed by the interconnected partial volumes (5), of the carrier overall volume with at least one second functional material (6), which performs a second function different from the first function.

8. Method according to Claim 7, characterized in that the carrier elements (3) are sheathed by metallizing the carrier elements (3).

9. Method according to one of Claims 7 and 8, characterized in that the carrier medium (2) is a woven strip.

10. Method according to Claim 9, characterized in that the carrier medium (2) is a woven glass-fibre strip or a woven carbon-fibre strip or a woven mineral-wool-fibre strip or a woven wire strip.

11. Method according to one of Claims 8 to 10, characterized in that the carrier elements (3) are metallized by physical vapour deposition of metal in a vacuum coating unit or by thermal spraying or by hot-dipping the carrier medium (2) into a bath of molten metal.

12. Method according to one of Claims 8 to 10, characterized in that the carrier elements (3) are metallized by chemical metal coating in a two-stage method, wherein the metallization of the carrier elements (3) comprises the following steps: ▪ an activation process and ▪ a metal coating process or in a three-stage method, wherein the metallization of the carrier elements (3) comprises the following steps: ▪ an activation process, ▪ a metal coating process and ▪ a metal-layer reinforcement process.