Battery structure

Abstract

The invention relates to a battery structure comprising a protective device, to a protective device for a battery housing, and to a fiber-matrix semi-finished product for producing the protective device.

Description

[0001] BATTERY STRUCTURE

[0002] SUBJECT OF THE INVENTION

[0003] The invention relates to a battery structure comprising a battery housing and / or a battery and a protective device, a protective device for a battery housing and / or a battery, and a fiber matrix semi-finished product for producing this protective device.

[0004] BACKGROUND OF THE INVENTION

[0005] Due to the growing demand for modern energy storage concepts, particularly in the field of electric vehicles, ever larger energy storage units, especially battery modules and batteries with the highest possible energy density, are being installed. An uncontrolled release of the chemicals and energy contained in the batteries can lead to catastrophic fires. Among other things, such a process can be triggered by mechanical damage to the batteries. Battery boxes made of fiber composite materials are increasingly being used because they offer advantages over metals in combining the requirements of fire protection, crash safety, insulation, and lightweight construction. Due to their typical layer-based structure and the process-related simultaneous production of the material and the resulting component, fiber composite materials offer much better adaptation options to the specific requirements of the component than metals.

[0006] Fiber composite components are already known from the state of the art which can better meet the above requirement profile, in particular by implementing different functionalities, such as flame-retardant properties or electromagnetic shielding.

[0007] US 2005 / 0170238 A1, for example, discloses a battery housing formed from a flame-resistant polymer composition of high-density polyethylene, which may include glass fiber reinforcement and a fire-resistant additive. During production, the fire-resistant additive is melt-mixed with the polyethylene to be protected, and the mixture is then pressed into the desired shape. US 2020 / 0152926 A1 describes a cover for a battery pack of an electric vehicle with a frame consisting of a layered composite. A first layer of the composite comprises a so-called "shear plate," which has a fiber-reinforced composite layer intended to counteract shear deformation during an impact.As a separate element, the composite layer comprises a fire- and abrasion-resistant second functional layer, which is deposited on the shear plate and which faces the battery when the shear plate is connected to the frame of the vehicle.

[0008] Although the fiber composite components described above can provide better protection against external influences such as flame activity or mechanical stress, in many applications, particularly in battery technology, this protection is inadequate and / or requires such a massive design of the protective device, such as the shear plate, that the use of composite materials is no longer competitive. Alternatively, significant amounts of flame-retardant or flame-extinguishing additives such as phosphates or aluminum hydroxide can be added to the composite component to improve fire protection properties. However, these adjustments lead to performance losses both on the process side (increased scrap) and on the product side (increased weight).

[0009] TASK

[0010] Against this background, the object of the present invention was therefore to provide a battery structure with a protective device with which the disadvantages described above can be overcome and which has an improved protective effect with regard to flame-abrasive and / or mechanical stresses, without this being accompanied by reduced processability and / or increased component weight and / or increased installation space.

[0011] DESCRIPTION OF THE INVENTION

[0012] This object is achieved according to the invention by a battery structure comprising a battery housing and / or a battery, and a protective device, wherein the protective device is preferably arranged on one of the inner sides of the battery housing and / or on the battery, wherein the protective device has a) fiber material comprising long and / or continuous fibers, and b) a matrix material, wherein the fiber material is at least partially, preferably completely, embedded in the matrix material, wherein the matrix material comprises or consists of an unsaturated compound, preferably an unsaturated polymer.

[0013] The invention relates to a battery structure, preferably for an electric vehicle, comprising a protective device and a battery. Alternatively or in addition to the battery, the battery structure comprises a housing for a battery. In the first case ("alternatively"), the battery structure does not necessarily have to have a battery, i.e., the invention already relates to a structure comprising only a battery housing with an additional protective device (and optionally a battery). In other words, the protective device is then an additional, separate element to the battery housing, which can optionally comprise a battery.

[0014] However, according to the invention, the protective device can also form the battery housing or a part of the battery housing, preferably the base or cover plate, for the battery, i.e., the protective device is the battery housing (or a part thereof). The battery structure then necessarily comprises a battery.

[0015] Battery modules are often used in modern battery structures. These are arrangements with multiple batteries that are combined in a generally closed frame and connected externally by a uniform boundary. Typically, several such structurally subordinate battery modules are arranged in a battery housing. The protective device according to the invention can be suitable for protecting a single module, i.e., arranged between the battery housing and the battery module. However, the protective device according to the invention can also protect multiple modules or even all modules.

[0016] Since the protective device according to the invention provides particular protection against thermal and / or flame stress, the protective device is preferably arranged between the battery housing and the battery module.

[0017] The protective device according to the invention can also be a so-called "intercell barrier" of a battery module, i.e., a protective plate that separates individual batteries of the battery module from one another. Such a plate prevents flames from one battery from spreading to the neighboring one(s) in the event of a fire. The protective device according to the invention is particularly preferably an "intercell barrier" between pouch cells of a battery module.

[0018] In a preferred embodiment, the protective device according to the invention is arranged on the inside of the battery housing, preferably between the battery and the battery housing. In another embodiment of the invention, the protective device according to the invention is arranged on the outside of the battery housing.

[0019] The protective device according to the invention is a fiber composite component which comprises a fiber material comprising or consisting of long and / or continuous fibers and a matrix material with an unsaturated compound, in particular an unsaturated polymer material. Unsaturated compounds are organic chemical compounds whose molecular structure contains one or more carbon-carbon double or triple bonds. In the context of the present invention, however, the term also includes molecular structures with carbon-nitrogen double or carbon-nitrogen triple bonds. Particular preference is given to polymers which have one or more carbon-carbon double or triple bonds. In this context, a polymer is understood to mean a chemical substance which contains more than 50% by weight, preferably more than 70% by weight, more preferably more than 80% by weight, even more preferably more than 90% by weight and most preferably more than 95% by weight.-% macromolecules.

[0020] "Macromolecules" are molecules composed of one or more identical or similar structural units, the constitutional repeating units (IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"), A.D. McNaught, A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), S.J. Chalk. ISBN 0-9678550-9-8). Such macromolecules have more than 10 repeating units, preferably more than 15 repeating units. The molecular mass is preferably at least 3,000 g / mol, preferably at least 5,000 g / mol, particularly preferably at least 7,000 g / mol, and most preferably at least 10,000 g / mol.

[0021] Polymers are typically produced by the reaction of monomers or oligomers containing one or more of the constitutional repeating units in a polymerization reaction. An oligomer is a molecule formed from several monomers and therefore composed of a large number of structurally identical or similar structural units. In the context of the invention, oligomers are referred to when the molecule is produced from a reaction of 2-10, preferably 2-8, preferably 3-7 monomers.

[0022] According to the invention, "resins" are understood to mean precursors of thermosetting plastics, i.e., polymers (cf. IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"), AD McNaught and A. Wilkinson, Blackwell Scientific Publications, Oxford (1997)), which can be used in particular as components of coatings, varnishes, and paints. These are particularly preferably resins, in particular resins obtained by polyaddition or polycondensation, in particular polyurethane (PU), polyester, polyamide, urea, melamine, formaldehyde, PVC, acrylic, or epoxy resins.

[0023] A "fiber composite component" is understood to be a material made of two or more bonded materials, which has different material properties than its individual components and which can serve as a component of a technical article. Such a component can be, for example, a plate or a housing, or a part of a housing, such as a base or cover plate. However, the term "fiber composite component" also encompasses fiber composite components that can form a technical article per se. The fiber composite component comprises at least one fiber material and a matrix material. The fiber composite component according to the invention is preferably a glass fiber reinforced plastic (GRP) or a carbon fiber reinforced plastic (CFRP).

[0024] The protective device according to the invention, ie the fiber composite component according to the invention, is suitable for protecting the battery and / or the battery housing and / or for protection from the battery, more precisely for protection from hazards posed by the battery. In particular, the protective device is suitable for protecting the battery and / or the battery housing from mechanical stress and / or for protection from thermal and / or flame stress posed by the battery, for example, if a fire occurs due to overheating or an uncontrolled chemical reaction of the battery chemicals. That is,that the protective device protects the battery and / or the battery housing from compressive and / or tensile and / or shear and / or impact loads, which are generally introduced from the outside and which can damage the battery, and secondly prevents or at least reduces thermal and / or flame stress on the components surrounding the battery (such as the battery housing, if present) in the event of a fire. Long fibers are understood to mean fibers with a length L = 1 to 50 mm, while continuous fibers (also unidirectional fibers) are understood to mean fibers with a length L > 50 mm. The length of the fibers of the fiber material is preferably > 30 mm. The use of continuous fibers in the protective device according to the invention and / or the fiber-matrix semi-finished product according to the invention is preferred. This results in components with particularly advantageous mechanical properties.

[0025] The matrix material of the protective device according to the invention serves to at least partially, preferably completely embed the fiber material and optionally also to at least partially, preferably completely embed an optional additive and / or to at least partially, preferably completely dissolve an optional additive. It holds the fibers of the fiber material in their position and transfers and distributes stresses between them. It is preferably a polymer material, in particular a thermosetting polymer material. This is preferably a thermosetting polymer material made from a resin and a hardener. Accelerators, activators, and release agents are preferably used in production, which then, within the meaning of the present invention, are preferably part of the matrix material.

[0026] Preferably, the matrix material has a substantially homogeneous chemical composition with the exception of an optionally incorporated additive and the incorporated fiber material, i.e. material boundaries, with the exception of the optionally incorporated additive and the incorporated fiber material, are not present at all or only to adjacent areas of the fiber composite component.

[0027] The spatial dimensions of the protective device itself are not restricted within the scope of the invention. The protective device can preferably be a plate, such as a fire protection plate. Preferably, the protective device is monolithic or a fiber composite sandwich plate, i.e. a plate-shaped component in a sandwich construction. In a sandwich construction, materials with different properties are combined in layers to form a component or semi-finished product. Typically, a sandwich plate comprises force-absorbing, solid, outer cover layers that are held at a distance by a relatively soft, lightweight core material. The core is preferably made of solid material (e.g., polyethylene, balsa wood), foam (e.g., rigid foam, metal foam), insulating material (e.g., rigid foam, mineral wool), or honeycomb grid (e.g., paper, cardboard, metal, plastic). It transfers any shear forces that occur and supports the outer cover layers.In a fiber composite sandwich panel, at least one of the layers, usually one of the cover layers, is formed from a fiber composite. Preferably, all outer cover layers are made of a fiber composite. Preferably, at least one, and preferably all, cover layers have a corrugated structure. The protective device preferably comprises surface, handling, protective, in particular UV-protective, marking, and color films, as well as film for improving electromagnetic compatibility (EMC). Also particularly preferred are cover functional layers such as protective films for transport and in-mold coatings, for example, for improved paintability.

[0028] The protective device may also comprise pores, i.e. air and / or gas inclusions, which, however, preferably do not constitute more than 5% by volume of the total volume of the protective device.

[0029] The protective device is often exposed to high mechanical loads in its intended use and therefore preferably has a particularly pronounced mechanical resistance and / or strength.

[0030] In a preferred embodiment of the invention, the fiber composite component, ie the protective device, therefore has a bending strength determined according to DIN EN ISO 14125:2011-05 of > 100 MPa, preferably > 200 MPa, more preferably > 400 MPa, even more preferably

[0031] > 600 MPa, even more preferably > 750 MPa and most preferably > 1,000 MPa, but normally not more than 20,000 MPa.

[0032] In a preferred embodiment of the invention, the fiber composite component has a flexural modulus of elasticity determined according to DIN EN ISO 14125:2011-05 of > 10 GPa, preferably

[0033] > 20 GPa, more preferably > 30 GPa, even more preferably > 50 GPa, even more preferably > 70 GPa and most preferably > 100 GPa, but usually not more than 1,000 GPa.

[0034] The protective device does not necessarily have to have the aforementioned mechanical properties. For example, the protective device can also be used in combination with a second protective device made of a metallic material, which then essentially serves to mechanically protect the battery and / or the battery housing. In a preferred embodiment of the invention, the battery structure therefore comprises a second protective device made of a metallic material.

[0035] The battery structure according to the invention can preferably be a stationary battery structure, but in another embodiment, it can also be a battery structure for a means of transport, for example a motor vehicle or an aircraft. The term "battery" within the meaning of the invention is not limited to primary batteries, i.e., batteries that can no longer be recharged, but also includes—and particularly preferably—accumulators, also called secondary batteries, i.e., rechargeable batteries. The battery is particularly preferably a lithium-ion accumulator, in particular a lithium-ion accumulator used for an electric vehicle.

[0036] Conventional carbon-based protective devices without unsaturated carbon-carbon or carbon-nitrogen bonds in the matrix act as sacrificial materials. This means that during a flame strike, e.g., if the battery explodes due to overheating, the fully saturated matrix materials are essentially completely oxidized to gaseous products such as CO2 and thus decompose. Filled epoxy composites are an example of this. Other non-carbon-based matrix materials, such as silicones, serve as insulators, but they are equipped with non-temperature-stable binders that fail early under thermal and mechanical loads.

[0037] The inventors were able to discover that the flame retardancy can be considerably improved by using a matrix material containing unsaturated carbon compounds. Without being bound to this theory, the inventors assume that the unsaturated carbon bonds in the matrix material act as carbonization centers during a flame strike, i.e. that in this case cyclization, dehydrogenation, and aromatization processes take place, creating a (partially) aromatic, carbon-like structure. These highly endothermic processes lead to the absorption and dissipation of the energy incident on the protective device as a result of the flame strike. The carbonized layer, acting as an insulator, also shields the heat from the matrix material lying beyond the carbonized layer. Electrical insulation can also be achieved by the non-carbonized regions of the matrix material. The long fiber orContinuous fiber structure stabilizes the carbon structure formed during flame impact and enables the absorption of mechanical loads that occur during a battery explosion, while allowing only minimal deformation of the protective device. In other words, the synergistic interaction of fiber material and matrix material enables carbonization without the resulting slightly brittle structure being damaged by cracks or similar. In most cases, this can prevent burn-through through the composite structure. In addition, the long and / or continuous fibers enable improved properties of the protective device with regard to mechanically transferable loads (tension, compression, shear) and improve the flame retardancy. In contrast to short fibers, inhomogeneities (e.g., local fiber volume content fluctuations) occur only to a minor extent in the component, and unstable structures such as exposed short fibers during combustion can be avoided.

[0038] These functions described above can be achieved in a locally focused manner through the localized use of the unsaturated compound. For example, an unsaturated, preferably thermosetting, polymer material can be arranged only in selected areas of the matrix material, particularly if only certain areas of the protective device are located in close proximity to the battery, battery housing, or battery module.

[0039] The matrix material according to the invention can also be a multi-component matrix material, in particular one formed from a mixture of different polymer materials, wherein at least one of these polymer materials is an unsaturated polymer material. The unsaturated polymer material is then preferably arranged in regions in the immediate vicinity of the battery, the battery housing, or the battery module. With such a multi-material matrix approach, for example, a phenolic resin, such as a novolak, can first be applied and consolidated in a mold at locally critical points during production, which, for example, are in direct contact with the battery during later use. In the subsequent step, a second saturated resin system (e.g., an epoxy resin) is applied to the consolidated structure, and the component is cured.

[0040] In a preferred embodiment of the invention, the matrix material is a matrix material cured by adding a hardener.

[0041] In a preferred embodiment of the invention, the weight proportion of the unsaturated, preferably polymeric and thermosetting, compound in the matrix material is > 10 wt.%, preferably > 20 wt.%, more preferably > 40 wt.%, even more preferably

[0042] > 60 wt%, even more preferably > 80 wt% and most preferably

[0043] > 90 wt.%. In a particularly preferred embodiment, the matrix material consists of the unsaturated compound, which is preferably in the form of a thermosetting polymer material.

[0044] In a preferred embodiment, the volume ratio of matrix material to fiber material in the protective device, ie the fiber composite component, is 8:1 to 1:10, preferably 5:1 to 1:8 and particularly preferably 2:1 to 1:5. In a preferred embodiment, the weight ratio of matrix material to fiber material in the fiber composite component is 5:1 to 1:20, preferably 3:1 to 1:10 and particularly preferably 1:1 to 1:8.

[0045] In a preferred embodiment, the volume ratio of matrix material to optional additive in the fiber composite component is 100:1 to 1:5, preferably 50:1 to 1:3 and particularly preferably 2:1 to 1:2.

[0046] In a preferred embodiment, the weight ratio of matrix material to optional additive in the fiber composite component is 100:1 to 1:10, preferably 50:1 to 1:6 and particularly preferably 4:1 to 1:4.

[0047] In a preferred embodiment, the weight proportion of fiber material in the total mass of the fiber composite component is 10 to 95 wt.%, preferably 20 to 90 wt.%, more preferably 30 to 85 wt.%, even more preferably 40 to 80 wt.% and most preferably 50 to 75 wt.%.

[0048] In a preferred embodiment, the volume ratio of matrix material to fiber material in the functional range is 8:1 to 1:15, preferably 2:1 to 1:10, and particularly preferably 1:1 to 1:10. By adjusting the fiber volume content within the limits described above, the carbonization behavior can be further improved.

[0049] In a preferred embodiment, the weight ratio of matrix material to fiber material in the functional range is 5:1 to 1:30, preferably 2:1 to 1:20 and particularly preferably 1:1 to 1:15.

[0050] In the protective device, the fiber volume content is preferably in a range of 30-70 vol.%, preferably 35-65 vol.%, even more preferably 40-60 vol.%, and most preferably 45-55 vol.%. This achieves suitable mechanical properties for the protection, in particular suitable ductility.

[0051] In a preferred embodiment of the invention, the fiber material has, at least in sections, preferably completely, a surface structure, preferably a textile surface structure, which is partially, substantially (i.e., more than 90 vol%), or even completely embedded in the matrix material. Particularly preferably, the surface structure is selected from the group consisting of non-crimp fabrics, knitwear, woven fabrics, braids, nonwovens, or mixtures thereof.

[0052] According to the invention, a nonwoven is understood to be a structure made of fibers of limited length, continuous fibers (filaments), or cut yarns of any type and origin, which have been joined together in any way to form a fiber layer and bonded together in any way. This excludes the crossing or entangling of yarns, as occurs in weaving, knitting, lacemaking, braiding, and the production of tufted products. This definition corresponds to the DIN EN ISO 9092 standard. According to the invention, the term "nonwoven" also includes felt materials. Films and papers, however, are not considered nonwovens.

[0053] For the purposes of the invention, braiding refers to the regular interlacing of several strands of flexible material. The difference from weaving is that in braiding, the threads are not fed at right angles to the main product direction.

[0054] Particularly preferred within the scope of the invention is the use of a fiber material in the form of a woven fabric. According to the invention, a woven fabric is understood to be a textile fabric consisting of two thread systems, warp (warp threads) and weft (weft threads), which, viewed on the fabric surface, intersect in a pattern at an angle of exactly or approximately 90°. Each of the two systems can be composed of several warp or weft types (e.g., ground, pile, and filling warp; ground, binding, and filling weft). The warp threads run in the longitudinal direction of the fabric, parallel to the fabric edge, and the weft threads run in the transverse direction, parallel to the fabric edge. The threads are connected to the fabric primarily by friction. For a fabric to be sufficiently slip-resistant, the warp and weft threads must usually be woven relatively tightly. Therefore, with few exceptions, the fabrics also have a closed appearance. This definition corresponds to the DIN 61100, Part 1 standard.

[0055] According to the invention, the terms woven and nonwoven also include tufted textile materials. Tufting is a process in which yarns are anchored into a woven or nonwoven fabric using a machine powered by compressed air and / or electricity.

[0056] According to the invention, knitwear refers to textile fabrics produced from thread systems by stitch formation. This includes both crocheted and knitted fabrics. According to the invention, a scrim is understood to be a fabric consisting of one or more layers of parallel, stretched threads. The threads are usually fixed at the intersection points. Fixation occurs either by fabric bonding or mechanically through friction and / or form fit. The scrim is preferably selected from a monoaxial or unidirectional, a biaxial, or a multiaxial scrim.

[0057] Preferably, the fiber material has an anisotropic structure, i.e., within the functional layer according to the invention, the fibers exhibit a specific fiber orientation. This can produce an anisotropic mechanical behavior of the layered composite.

[0058] The fibers of the fiber material are preferably selected from the group consisting of glass fibers, carbon fibers, ceramic fibers, basalt fibers, boron fibers, steel fibers, polymer fibers such as synthetic fibers, in particular aramid and nylon fibers, or mixtures of the aforementioned. Glass fibers and carbon fibers are particularly preferred. Using such fibers, protective devices according to the invention with particularly high mechanical resistance can be produced.

[0059] Carbon fibers are particularly preferred for protective devices for aircraft applications, particularly due to their weight advantage and higher modulus of elasticity, while glass fibers are particularly preferred in automotive applications.

[0060] In another preferred embodiment, the fibers of the fiber material are natural fibers, in particular natural polymer fibers.

[0061] Natural fibers are fibers that originate from natural sources such as plants, animals, or minerals and can be used directly without further chemical conversion reactions. Examples of these fibers according to the invention are flax, jute, sisal, or hemp fibers, as well as protein fibers or cotton. Regenerated fibers, i.e., fibers produced from naturally occurring, renewable raw materials using chemical processes, can also be used according to the invention.

[0062] Corresponding fiber materials are characterized by improved recyclability and thus a particularly high level of sustainability.

[0063] The one or more unsaturated carbon-carbon and / or carbon-nitrogen bonds of the unsaturated compound are converted into a (partially) aromatic, carbonaceous structure during a flame treatment. The inventors assume that the use of an unsaturated carbon-nitrogen bond results in N2 elimination, which is part of the carbonization process. In a preferred embodiment of the invention, the functional group therefore has a carbon-nitrogen bond, in particular a carbon-nitrogen double bond.

[0064] In another preferred embodiment of the invention, the functional group has an unsaturated carbon-carbon bond, in particular a carbon-carbon double bond.

[0065] More preferably, the functional group has two, three, four, five or more unsaturated carbon-carbon bonds and / or unsaturated carbon-nitrogen bonds.

[0066] In a preferred embodiment of the invention, the unsaturated compound is a thermosetting polymer material having at least one constitutional repeating unit which has at least one functional group comprising an unsaturated carbon-carbon bond and / or an unsaturated carbon-nitrogen bond.

[0067] In a preferred embodiment, the functional group has two or more bonds selected from the group consisting of unsaturated carbon-carbon bonds and unsaturated carbon-nitrogen bonds, and at least two of these bonds are conjugated. Conjugation of the unsaturated bonds facilitates the formation of an aromatic structure, whereby the carbonization processes proceed preferentially and thus to a greater extent.

[0068] Preferably, the functional group is part of an aromatic system, such as part of a furanyl, thiophenyl, pyrolyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, phenyl, benzoyl, hydroxyphenyl, or pyridinyl group. The presence of an aromatic system energetically favors further aromatization during the carbonization process. The aforementioned groups are particularly preferably part of a repeating unit(s) when the unsaturated compound is a polymer.

[0069] The unsaturated compound is preferably a thermosetting polymer selected from the group consisting of phenolic resins, cured melamine resins, cured furan resins, and cured polyurethane resins. Materials obtained from the curing of phenolic resins, preferably novolaks, are particularly preferred. The thermosetting polymer materials are preferably almost completely crosslinked, where "almost completely" means that at least 80% of the potentially crosslinkable functional groups are crosslinked.

[0070] The thermosetting polymer material is preferably a phenolic resin obtained by crosslinking a phenol-formaldehyde resin. The molar ratio of formaldehyde to phenol in the curable phenol-formaldehyde resin is particularly preferably in the range between 1:0.4 and 1:2.5, in particular 1:1.2 to 1:2.

[0071] The thermosetting polymer material according to the invention is preferably obtained by reacting a resin, such as a phenolic resin, with a hardener. The hardener is preferably selected from the group consisting of formaldehyde donors, such as hexamethylenetetramine, or melamine or urea condensates containing methylol groups. The hardeners are preferably used in an amount of 2.5 to 50 wt.%, preferably 5 to 15 wt.%, based on the phenolic resin.

[0072] In a preferred embodiment of the invention, the matrix material and / or the unsaturated compound has a carbon yield upon thermal pyrolysis of > 40%, preferably > 50%, even more preferably > 55%, even more preferably > 60%, and most preferably > 65%. The carbon yield can be determined in a thermogravimetric analysis, whereby the thermal treatment of an approximately 30 mg sample is carried out in an N2 atmosphere (60 ml / min purge gas rate) and a linear heating program is run from 20 °C to 1000 °C at a heating rate of 10 °C / min. The carbon yield corresponds to the ratio of residual mass to the initial mass of the matrix material or the unsaturated compound. With a correspondingly high yield, the advantages of the invention are particularly pronounced.

[0073] The matrix material of the protective device according to the invention may further comprise an additive.

[0074] The additive is particularly preferably a flame retardant, which is preferably selected from the group consisting of halogenated and / or nitrogen-based flame retardants, inorganic flame retardants such as graphite salts, aluminum trihydroxide, antimony trioxide, ammonium polyphosphate, aluminum diethylphosphinate, mica, muscovite, guanidines, triazines, sulfates, borates, cyanurates, salts thereof, and mixtures thereof. This can further increase the flame retardant activity of the protective device. In contrast to the protective devices known from the prior art, a significantly lower content of additives, in particular flame retardants, can be used due to the intrinsic flame retardant activity as a result of the carbonization behavior, which has a particularly positive effect on the mechanical properties of the protective devices. In a preferred embodiment of the invention, the matrix material has < 50 wt. % additives, preferably < 45 wt.-% additives, more preferably < 40 wt.% additives, even more preferably < 35 wt.%, even more preferably < 30 wt.% additives and most preferably < 25 wt.% additives, but preferably also > 1 wt.%.

[0075] In other preferred embodiments, the additive is selected from the group consisting of antioxidants, light, in particular UV stabilizers, plasticizers, foaming agents, electrical conductors, thermal conductors, dyes, fillers for improving mechanical properties such as impact modifiers or rubber or thermoplastic particles as well as mixtures of the aforementioned.

[0076] The additive can be dissolved or dispersed in the matrix material. If dispersed, it is preferably in the form of a powder, flakes, tubes, or mixtures of the aforementioned forms.

[0077] If the additive is a flame retardant, it is preferably selected from the group of active, i.e., cooling, flame retardants or from the group of passive, i.e., insulating, flame retardants. The flame retardant is particularly preferably an intumescent flame retardant.

[0078] Finally, the matrix materials according to the invention can also contain wetting agents. Wetting agents are surface-active substances that typically have a hydrophobic and a hydrophilic molecular moiety. A distinction is made between nonionic, anionic, and cationic wetting agents. Wetting agents reduce the viscosity of the resin. This improves the penetration of the fiber material, ultimately leading to a stronger bond between the fiber material and the matrix material. The synergistic effect, particularly the stabilization of the (partially) carbonized structure, is thereby enhanced.

[0079] Nonionic wetting agents include, for example, esters and amides of fatty acids (saturated or unsaturated carboxylic acids, which generally have 4 to 26 carbon atoms in the molecule), fatty amines (primary amines, which generally have 6 to 22 carbon atoms in the molecule), or polyethylene glycol ethers or polypropylene glycol ethers of alcohols, alkylphenols, or fatty acid alkanolamides. Anionic wetting agents include, for example, salts of alkylammonium, ionic, or alkylsuccinic acid, alkylsulfonates, fatty acid ester sulfonates, perforated alkylsulfonates, or sulfated fatty acid amides. Cationic wetting agents are substances such as fatty amine salts, salts of alkylenediamines and polyamines, alkylbenzylammonium salts, or alkylpyridinium salts.

[0080] The fiber composite component, ie, the protective device, is preferably designed integrally, ie, in one piece, i.e., monolithically. Particularly preferably, the fiber composite component is obtained by integral curing during its manufacture. In another preferred embodiment, the fiber composite component is a fiber composite sandwich panel, ie, a panel-shaped component with a sandwich construction.

[0081] The invention also relates to a protective device for a battery housing and / or a battery and / or a battery module as defined in one of the claims and the preceding and following sections of the description text.

[0082] Particularly preferably, the protective device is a battery housing, in particular a battery housing for the battery of an electric vehicle, such as a lithium-ion accumulator.

[0083] The protective device is preferably a vehicle component, in particular a motor vehicle component such as a body component. Particularly preferably, the protective device is an underbody protection (also called an impact protection plate or underride protection) or bumper, or a battery housing, or a battery housing part, and is preferably in the form of a protective plate.

[0084] The protective device can also be part of an aircraft or spacecraft, a rail vehicle component, or a part of the aforementioned. Further preferred motor vehicle components are selected from the group consisting of trunk loading floors, instrument panels, door and roof panels, underbody protection parts, structural components, wheel housings, engine compartment parts, brake and clutch linings and discs, sound insulation, shear panels, and seals.

[0085] Particularly preferred is use as part of a battery housing (which does not necessarily have to be part of a motor vehicle), especially for a lithium-ion battery. The fiber composite component is particularly preferably the base or cover plate.

[0086] The protective device can also be an "intercell barrier." The invention also relates to a fiber-matrix semi-finished product, preferably a prepreg, for producing a protective device according to the invention, comprising a fiber material comprising or consisting of long and / or continuous fibers and a preferably curable, in particular thermosetting, resin composition comprising an unsaturated compound, preferably in the form of a resin with at least one constitutional repeating unit, wherein the fiber material is at least partially, preferably completely, embedded in the preferably thermosetting resin composition.

[0087] The at least one constitutional repeating unit of the preferably used resin comprises at least one functional group having an unsaturated carbon-carbon bond or an unsaturated carbon-nitrogen bond.

[0088] Preferably, the fiber-matrix semi-finished product is designed such that at least one surface of the semi-finished product is substantially completely, i.e., more than 70%, preferably completely, covered with matrix material. Such a fiber-matrix semi-finished product is characterized by particularly good processability. In particular, contact with additional fiber layers to produce complex components can be made via the completely covered side, so that the smallest possible interlaminar pore volume is generated. The resulting protective devices can therefore withstand particularly strong mechanical loads. The invention also relates to a protective device obtained by the thermal joining of such semi-finished products.

[0089] The preferably used curable resin composition of the fiber-matrix semi-finished product preferably comprises or is a phenolic resin, in particular a novolak, which is particularly preferably dry, i.e., contains less than 10 wt. %, preferably less than 5 wt. %, even more preferably less than 1 wt. % solvent. Such dry, preferably thermosetting resin compositions of the fiber-matrix semi-finished product are preferably obtained by partial curing with a curing agent, preferably an amine curing agent such as hexamethylenetetramine. The aforementioned phenolic resins, in particular novolaks, particularly in the aforementioned preferred embodiments, exhibit high storage and handling stability (in particular low or no tackiness) at room temperature, but also up to temperatures of 60°C.This high stability is particularly pronounced when the phenolic resins, in particular novolaks, are in the "B-state," since then further polymerization and crosslinking reactions do not occur or only occur to a minor extent. This is particularly preferably achieved by partially curing the preferably thermosetting compositions with an amine curing agent, such as hexamine. The preferably thermosetting resin composition, which in particular comprises a novolak, preferably has a glass transition temperature (T). g ) of > 4 °C, preferably > 8 °C, more preferably > 12 °C, even more preferably > 15 °C and most preferably > 20 °C. By using a novolak, in particular with the T g - values, the fiber-matrix semi-finished product is prevented from feeling sticky. This also results in particularly good cuttability of the fiber-matrix semi-finished product.

[0090] The weight fraction of the fiber material in the fiber-matrix semi-finished product is preferably in the range of 25-60 wt.%, preferably 30-55 wt.%, even more preferably 35-50 wt.%, and most preferably 35-50 wt.%. Within these value ranges, both dry spots in the fiber-matrix semi-finished product and excessive matrix outflow during processing can be avoided.

[0091] The use of a novolak generally prevents coloration, such as that which occurs with resoles, in the fiber-matrix semi-finished product and / or the protective device.

[0092] When using a phenolic resin for the fiber-matrix semi-finished product, in particular a novolak, the heat-curable composition is preferably in the so-called "B-stage," i.e. the composition is still swellable and meltable, but is already insoluble in solvents. This state is generally achieved by thermal treatment at a maximum temperature of 160°C. Such resins enable, in particular, the simple integration of surface, handling, protective, in particular UV-protective, marking, and color films, as well as films to improve electromagnetic compatibility (EMC). Particular preference is also given to cover functional layers such as protective films for transport and in-mold coating, for example for better paintability. The fiber-matrix semi-finished product therefore preferably comprises such films. The protective device according to the invention also preferably comprises such films.The use of phenolic resins, especially in the “B-stage”, also enables near-net-shape pressing due to their low flowability.

[0093] In terms of process technology, the use of the above-described phenolic resins in the "B-stage", particularly novolaks, enables further simplification, as the reaction is already very advanced before the final curing during the final component production. This simplifies and accelerates the overall process. When using a novolak with an amine hardener, only ammonia is released during the final curing of the fiber-matrix semi-finished product, which produces the protective device according to the invention, but the basic structure of the curable composition in the "B-stage" is no longer changed. This leads to a high degree of application variability (a type of "phenolic resin-based organosheet") and a very short reaction time during the final curing step. In addition, ammonia escapes from the resin matrix much more easily, so that compared to water-separating curing (e.g.When cured with compounds containing hydroxymethyl groups, significantly less pore formation is observed. This allows for the production of thicker-walled and more stable protective devices.

[0094] The invention also relates to a system (“kits-of-parts”) for producing a fiber-matrix semi-finished product, as defined in claim 14 and above, wherein the composition comprises a fiber material and a preferably thermosetting resin composition in powder form. The resin composition is preferably dry, i.e., contains less than 10 wt.%, preferably less than 5 wt.%, even more preferably less than 1 wt.%, of solvent. The dry, preferably thermosetting compositions preferably contain hardeners, in particular amines such as hexamethylenetetramine (also “hexamine”). The preferably thermosetting composition is preferably in the “A state,” in particular in the “A2 state,” in this powdered system.

[0095] The addition of additives can be carried out easily during handling using a powder spreader. The additives can be mixed in as a separate powder. Preferably, the addition of additives, in particular the hardener, is carried out in such a way that they are essentially homogeneously distributed in the resin powder. In contrast to the use of individual powders of thermosetting composition and hardener, segregation of the powders due to density differences during the manufacturing process can be avoided, thereby ensuring a homogeneous distribution of the hardener in the fiber-matrix semi-finished product. The system therefore preferably also comprises a hardener that is dissolved and / or dispersed in the powdered, thermosetting resin composition. In another embodiment, the system comprises the hardener as a separate powder. However, the additives, in particular the hardener, are preferably dissolved and / or dispersed in the resin composition.

[0096] The invention also relates to the use of the protective device according to the invention in a battery structure. The invention also relates to the use of the protective device according to the invention for protecting a battery and / or a battery housing and / or for protection against a battery, more precisely for protection against hazards posed by a battery. The invention also relates to the use of an unsaturated compound, in particular a thermosetting polymer material having at least one constitutional repeating unit which has an unsaturated carbon-carbon bond and / or an unsaturated carbon-nitrogen bond, in a protective device for a battery housing and / or a battery and / or a battery module, in particular in a protective device for a battery housing and / or a battery and / or a battery module of an electric vehicle.Particularly preferred is the use of a thermosetting polymer material obtained from a phenolic resin, in particular a novolak, by curing as a matrix material for a protective device for a battery housing, in particular in a protective device for a battery housing of an electric vehicle. The invention also relates to the use of a thermosetting polymer material obtained from a phenolic resin, in particular a novolak, by crosslinking as a matrix material in a battery structure comprising a protective device for a battery housing, and a battery housing and / or a battery and / or a battery module, wherein the protective device and / or the battery and / or the protective device and the battery housing and / or the protective device and the battery module are preferably connected to one another.Particularly preferably, the protective device is arranged, in particular fastened, on one of the inner or outer sides of the battery housing and / or the battery.

[0097] The invention also relates to the production of a fiber-matrix semi-finished product and a protective device made from this fiber-matrix semi-finished product. A method for producing the protective device comprises a first step for producing the fiber-matrix semi-finished product and a subsequent thermal finishing step, and is presented below as an example.

[0098] Step 1 : Production of the fiber matrix semi-finished product by powder lamination

[0099] In the first step of manufacturing the protective device, novolak with a weight-average molecular weight of -500 g / mol is applied to a textile, melted at a temperature of 120-130 °C and then pressed into the fiber material by applying a force (> 5 N / cm 2) is introduced into the textile structure using a double-belt press. Cooling produces a fiber-matrix semi-finished product. The degree of conversion, i.e., the extent of partial curing, of the thermosetting matrix material can be regulated by varying the pressing time, temperature, and / or pressure. This allows the brittleness of the material to be controlled. After cooling, the novolak is in the "B-stage."

[0100] Step 2: Thermal finalization to produce the protective device

[0101] In the subsequent second process step, the fiber-matrix semi-finished product obtained in step 1 is formed into the desired final contour (e.g., L-profile, etc.) at elevated temperature using shaping tools (approx. 140-170°C). Preferably, several fiber-matrix semi-finished products can be stacked on top of each other, i.e., a so-called stack, in order to obtain a uniform end product after final curing.

[0102] Steps 1 and 2 can be performed both continuously, i.e., directly following one another, or discontinuously, i.e., separated in time. Using the method according to the invention, significantly thicker-walled components, such as laminates, can be produced than those known from the prior art. Conventional potting resin systems are generally difficult to process due to the resin quantity, the impregnation distance, and the exothermic nature, so the component thickness is limited. This applies particularly to the conventional wet-spraying process, in which, above a certain thickness, the resin system can no longer fully infiltrate the fiber layers.

[0103] When using an RTM process, however, one or more gate points are used, which usually cannot be perfectly concealed. Furthermore, the gate always results in an uneven distribution of the matrix material, as the fiber material is very difficult to fully infiltrate due to the problems described above, especially with large structures.

[0104] Since in the process according to the invention the final component is achieved by joining thin layers that are almost completely impregnated with resin, these problems do not exist here.

[0105] In a preferred embodiment of the invention, the protective device according to the invention is therefore a protective plate having a thickness of > 1 mm, preferably > 1.5 mm, even more preferably > 2.5 mm, even more preferably > 3.5 mm, and most preferably > 5 mm. In such a protective plate, the fiber material is preferably substantially completely embedded (i.e., more than 95 vol%). This protective device is preferably obtained by a process comprising the following steps: I) producing the fiber-matrix semi-finished product by a) applying a dry, powdery, and thermosetting resin composition, in particular a novolak, to produce a phenolic resin, to a textile, b) melting the resin composition at 100-150 °C, and c) applying a force to infiltrate the textile with the resin,

[0106] II) Production of the protective device from one or more of the fiber matrix semi-finished products produced under step I) by a) Optionally: stacking several fiber matrix semi-finished products in a press b) pressing the fiber matrix semi-finished product or the stack of fiber matrix semi-finished products at a temperature of 150 °C to 250 °C, in particular 160 °C to 180 °C.

[0107] The process according to the invention also enables the use of fine-meshed fabrics with a low basis weight (< 200 g / m 2 ), which cannot be processed in conventional manufacturing processes, such as wet pressing, due to the difficulty of infiltration. The invention therefore preferably relates to a fiber-matrix semi-finished product and a protective device comprising fine-mesh fabric with a basis weight of < 200 g / m 2 , preferably < 150 g / m 2 , even more preferably < 120 g / m 2 , and most preferably < 90 g / m 2. Preferably, the protective device with a corresponding trade is obtained by a method comprising the steps defined above.

[0108] FIGURE LIST

[0109] The present invention is explained in more detail below with reference to the exemplary embodiments shown in the figures.

[0110] Fig. 1 and Fig. 4 schematically show step 1 of a method for producing a protective device according to the invention.

[0111] Fig. 2 shows schematically step 2 of a method for producing a protective device according to the invention.

[0112] Fig. 3 shows schematically a multi-matrix protection device with locally different matrix systems.

[0113] DESCRIPTION OF AN EMBODIMENT

[0114] Fig. 1 and Fig. 4 show schematically and by way of example a method for producing the protective device according to the invention, ie the composite component, as can be used for example for a cover or base of a battery housing for an electric vehicle.

[0115] To manufacture such a composite component, a winder is loaded with a glass fabric. The total grammage of the glass fabric and the distribution of the proportions of different fiber orientations (e.g., at 0°, + and - 45°, and 90° relative to the vehicle's longitudinal axis) are determined during the design process according to the mechanical and other loads on the cover / floor. In a simple basic structure, the proportions of the orientations at 0°, - 45°, 45°, and 90° are equal, resulting in a so-called quasi-isotropic laminate.

[0116] With the help of the unwinder, the glass fabric is fed to a powder lamination system with a powder spreader. With the help of the powder spreader, a resin-hardener mixture in the form of a powder is distributed evenly over the fabric and then fed into a double-belt press (press temperature -120 °C). The resin material is a novolak resin with a weight-average molecular weight of -500 g / mol, and the hardener is hexamine. The resin material is thereby pressed into the fabric and the reinforcing fibers are embedded in the resin. This process step is shown schematically in Figures 1 and 4. After cooling to room temperature, the resulting prepreg material is cut to size and / or rolled up or stacked. The resulting fiber-matrix semi-finished product, in this case the prepreg material, is storage-stable at room temperature (-23 °C) (i.e.there is no conversion to the “C-state” over a period of at least 2 days) and is essentially tack-free.

[0117] To manufacture the protective device, the semi-finished product is cut to the desired thickness in step 2 of the process. The stack is then placed in an open press with a crimping edge. The press is closed, and the component is pressed at a temperature of 160-170 °C using a controlled displacement method, thus fully curing the matrix material. The curing time is several minutes. This process step is schematically illustrated in Figure 2.

[0118] The component is then removed from the mold and moved on to the final processing steps.

[0119] Depending on the arrangement of the battery cells in the housing, certain areas of the cover are exposed to particularly high temperatures in the event of a battery fire. In one embodiment of the invention, the matrix material of the protective device therefore comprises an unsaturated matrix material, e.g., a novolak, only at these locations exposed to particularly high stresses. Such locations are highlighted in black in the schematic representation in Figure 3.

[0120] Reference symbol

[0121] 1 Curable resin composition in powder form

[0122] 2 Textile fiber material layer

[0123] 3 Fully resin-coated surface side fiber matrix semi-finished product

[0124] 4 Fiber-matrix semi-finished product

[0125] 5 Protective device

[0126] 6 Novolak-enriched matrix zone of the protective device

[0127] 7 unwinders with glass fiber scrim

[0128] 8 powder shakers

[0129] 9 Heating zone of the double belt press

[0130] 10 Cooling zone of the double belt press

[0131] 11 Winding device for semi-finished products

Claims

Patent claims Battery structure comprising a battery housing and / or a battery, and a protective device, wherein the protective device has a) fiber material comprising long and / or continuous fibers, and b) a matrix material, wherein the fiber material is at least partially, preferably completely, embedded in the matrix material, characterized in that the matrix material comprises or consists of an unsaturated compound, preferably an unsaturated polymer. Battery structure according to claim 1, wherein the protective device has the fiber material at least in sections, preferably completely, in the form of a preferably textile surface structure. Battery structure according to claim 2, wherein the textile surface structure is selected from the group consisting of scrims, woven fabrics, nonwovens or combinations of the aforementioned.Battery structure according to one of the preceding claims, wherein the fibers of the fiber material are selected from the group consisting of glass fibers, carbon fibers, basalt fibers, ceramic fibers, steel fibers, polymer fibers such as synthetic fibers, in particular aramid and nylon fibers, or natural polymer fibers such as flax, hemp, or protein fibers. Battery structure according to one of the preceding claims, wherein the unsaturated compound is a thermosetting polymer material with at least one constitutional repeating unit having at least one functional group comprising an unsaturated carbon-carbon bond and / or an unsaturated carbon-nitrogen bond.

6. The battery structure of claim 5, wherein the functional group comprises an unsaturated carbon-carbon double bond.

7. The battery structure according to claim 5 or 6, wherein the functional group has two or more bonds selected from the group consisting of unsaturated carbon-carbon bonds and unsaturated carbon-nitrogen bonds, and wherein at least two of these bonds are conjugated.

8. Battery structure according to one of claims 5 to 7, wherein the at least one functional group is selected from the group consisting of carbon-carbon double bonds, carbon-carbon triple bonds, imino groups, aromatics and nitrile groups and / or the at least one functional group is part of one of the following radicals: alkenyl, alkynyl, nitrile, furanyl, thiophenyl, pyrolyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, phenyl, benzoyl, hydroxyphenyl or pyiridinyl.

9. Battery structure according to one of the preceding claims, wherein the protective device is designed in one piece or has a sandwich construction.

10. Battery structure according to one of the preceding claims, wherein the unsaturated compound is a thermosetting polymer produced by curing a curable resin composition, wherein the resin of the resin composition is preferably selected from the group consisting of phenolic resins, in particular novolaks, melamine resins, polyurethane resins and mixtures of the foregoing.

11. Battery structure according to one of the preceding claims, wherein the battery structure comprises a battery housing and the protective device is the battery housing or a part of the battery housing, preferably a base or cover plate.

12. A protective device for a battery housing and / or battery and / or a battery module as defined in any one of the preceding claims.

13. Protective device according to one of the preceding claims, wherein the protective device is a means of transport component, preferably a motor vehicle component or a part thereof, preferably a component of a battery housing, particularly preferably the base or cover plate. A fiber-matrix semi-finished product for producing a protective device according to one of the preceding claims, comprising a) a fiber material comprising long and / or continuous fibers, b) a curable resin composition comprising an unsaturated compound, wherein the fiber material is at least partially, preferably completely, embedded in the curable resin composition. Use of an unsaturated compound, in particular a thermosetting polymer material with at least one constitutional repeating unit having an unsaturated carbon-carbon bond and / or an unsaturated carbon-nitrogen bond, in a protective device for a battery housing and / or a battery, in particular in a protective device for a battery housing of an electric vehicle.

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