DE202020103596U1 - Fire protection coating and fire protection cover - Google Patents

Abstract

Fire protection coating (120) for a battery assembly of an electric vehicle comprising an epoxy resin layer (210) and a ceramic fiber layer (220).

Description

TECHNICAL AREA

The present invention relates to the field of material coatings and relates to a fire protection coating. The invention also relates to a fire protection cover based thereon and a housing for a battery that contains such a cover.

TECHNICAL BACKGROUND

One problem with commercially available lithium-ion batteries is the so-called thermal runaway, a self-reinforcing heat-producing process: a local short circuit of the internal electrodes, for example due to contamination or damage to the separator, releases so much heat and heats them up Environment to such an extent that surrounding or neighboring parts and components are damaged. This creates flames with temperatures in the range of 1200 ° C. In addition, a high mechanical pressure is often generated here, and the resulting flame cone may act directly on the surrounding surfaces. This process can extend over several accumulator cells, of which a typically used accumulator consists and which can be combined in cell modules, and very quickly release large parts of the energy stored in the accumulator.

In order to prevent thermal runaway, the prior art (see e.g. DE 10208277 A1 and DE 10238945 A1 ) known special separators, which are supposed to counteract a thermal runaway. However, despite the use of these and other technologies, thermal runaway still represents a potential hazard. Especially with regard to the increasing spread of electric vehicles with large-scale, personal cell modules, there is a great need to further improve the safety for the users of such vehicles by thermal runaway, or at least the potentially serious consequences thereof, can be better prevented.

The present invention is therefore based on the technical problem of providing a product which in batteries, and here in particular in lithium-ion accumulators, minimizes the spread and the consequences of thermal runaway.

SUMMARY

According to a first aspect of the invention, a fire protection coating for a battery arrangement of an electric vehicle is provided, which comprises an epoxy resin layer and a ceramic fiber layer.

Such a fire protection coating offers a high degree of flexibility, since it can be applied to various materials such as metal and / or ceramic and / or carbon fibers and / or plastic and can easily be adapted to the shape of the carrier structure. Furthermore, such a coating is easy and relatively inexpensive to manufacture. The epoxy resin layer can be used to apply or glue the ceramic fiber layer to the carrier structure (carrier material, substrate). Such a multi-layer system can be temperature-resistant up to very high temperatures of more than 1600 ° C and can also withstand high mechanical pressure.

According to a second aspect, the invention also relates to fire protection coverings comprising a carrier structure to which a fire protection coating according to the invention is applied.

Such fire protection covers allow the fire-resistant or temperature-resistant design of vehicle battery housings, covers and capsules, in particular for holding lithium-ion accumulators.

Further aspects and features emerge from the dependent claims, the attached drawing and the following description of embodiments.

Figure list

• 1 eine schematische Darstellung eines typischen Aufbaus eines Gehäuses einer Batterie mit einer erfindungsgemäßen Brandschutzabdeckung;
• 2a eine schematische Darstellung eines ersten Ausführungsbeispiels eines Aufbaus einer erfindungsgemäßen Brandschutzabdeckung;
• 2b eine schematische Darstellung eines zweiten Ausführungsbeispiels eines Aufbaus einer erfindungsgemäßen Brandschutzabdeckung;
• 2c eine schematische Darstellung eines dritten Ausführungsbeispiels eines Aufbaus einer erfindungsgemäßen Brandschutzabdeckung;
• 2d eine schematische Darstellung eines vierten Ausführungsbeispiels eines Aufbaus einer erfindungsgemäßen Brandschutzabdeckung;
• 2e eine schematische Darstellung eines fünften Ausführungsbeispiels eines Aufbaus einer erfindungsgemäßen Brandschutzabdeckung;
• 3 ein Ablaufdiagramm eines erfindungsgemäßen Verfahrens zur Herstellung einer Brandschutzabdeckung.

Embodiments will now be described by way of example and with reference to the accompanying drawings. It shows:

• 1 a schematic representation of a typical structure of a housing of a battery with a fire protection cover according to the invention;
• 2a a schematic representation of a first embodiment of a structure of a fire protection cover according to the invention;
• 2 B a schematic representation of a second embodiment of a structure of a fire protection cover according to the invention;
• 2c a schematic representation of a third embodiment of a structure of a fire protection cover according to the invention;
• 2d a schematic representation of a fourth embodiment of a Structure of a fire protection cover according to the invention;
• 2e a schematic representation of a fifth embodiment of a structure of a fire protection cover according to the invention;
• 3 a flow chart of a method according to the invention for producing a fire protection cover.

DESCRIPTION OF EMBODIMENTS

Before describing the embodiment in detail with reference to FIG 1 First, general explanations of the embodiments follow.

A ceramic fiber layer describes flexible, in particular textile nonwoven, woven or knitted layers that are essentially formed from ceramic fibers. However, it can also contain other fibers and components that are necessary or helpful for production, processing and function (e.g. equipment, coatings, functional fibers, etc.)

For the purposes of the invention, an epoxy resin layer is to be understood as meaning a layer (layer) which comprises hardened epoxy resin (i.e. including any hardener used), the hardened epoxy resin more than 50% by volume of the layer, preferably at least 60% by volume, particularly preferably at least 70% by volume and very particularly preferably 90% by volume or more. Equivalently, a ceramic fiber layer in the sense of the invention is a layer (layer) that contains ceramic fibers, the ceramic fibers more than 50% by volume of the layer, preferably at least 60% by volume, particularly preferably at least 70% by volume and most preferably 90 % By volume or more. It is conceivable here that the epoxy resin layer comprises a certain proportion, for example 40% by volume or less or for example 20% by volume or less, of ceramic fibers. Conversely, the ceramic fiber layer can also contain hardened epoxy resin, for example 40% by volume or less or, for example, 20% by volume or less. A certain proportion of hardened epoxy resin in the ceramic fiber layer can serve to bond the ceramic fibers and thus to mechanically stabilize the layer. A fiber-plastic composite is formed from ceramic fibers and hardened epoxy resin. Furthermore, it is also conceivable that further materials are contained in an epoxy resin layer and / or a ceramic fiber layer.

In order to achieve an increased fire protection effect or fire-retardant effect (that is to say a resistance to the spread of fire) and heat resistance, the fire protection coating can furthermore comprise two or more, for example three, epoxy resin layers. It is also conceivable that the fire protection coating comprises two or more, for example three, ceramic fiber layers in order to increase the fire protection effect.

It has proven to be particularly advantageous for the fire protection effect of such a fire protection coating consisting of three or more layers (ceramic fiber layers and / or epoxy resin layers) if these layers occur or are arranged alternately, i.e. alternately, in the fire protection coating. A fire protection coating based on the carrier structure in the sequence epoxy resin layer, ceramic fiber layer, epoxy resin layer, ceramic fiber layer may be mentioned here as an example.

A wide variety of values are conceivable for the layer thickness of the fire protection coating. Typical layer thicknesses are in the range from 200 µm to 10,000 µm, in particular in the range from 500 µm to 5,000 µm. Here and in the following, layer thickness is to be understood as the average dry film thickness (DFT), i.e. the average layer thickness that remains on the substrate, i.e. the carrier structure, after curing of the applied material.

The layer thickness of a ceramic fiber layer of a fire protection coating according to the invention is preferably 200 μm to 10,000 μm and particularly preferably 500 μm to 1,000 μm, although a wide variety of layer thicknesses and layer thickness combinations (i.e. different layer thicknesses for different layers) are conceivable. Such layer thicknesses are also conceivable for an epoxy resin layer of the fire protection coating.

A typical structure can also be such that a 750 µm thick fire protection coating is first applied to a surface or a surface area of a carrier structure, and an approximately 1000 µm thick fleece (ceramic fiber layer) is pressed into this not yet hardened layer. Then another layer of fire protection coating, also about 750 µm thick, is applied to the ceramic fiber layer. The ceramic fiber layer designed as a fleece is not completely soaked by the fire protection coating, but is merely wetted so that it penetrates into the outer surfaces and is thus glued to the fire protection coatings and over them to the surface of a carrier structure, so that no delamination occurs.

In particular, the layer thicknesses can also vary from layer to layer, for example a smaller layer thickness can be selected for all epoxy resin layers than for the ceramic fiber layers. For layers located further out (that is, with increasing distance from the carrier structure), smaller or larger layer thicknesses could also be selected. For example, a particularly large layer thickness could be selected for the last (outermost) layer in order to ensure a particular mechanical resistance of the layer. It is also conceivable that the layer thicknesses vary depending on the location, for example in order to particularly protect an area of a carrier structure that is at great risk from fire or high temperatures. In general, a wide variety of characteristics with various layer thicknesses and layer thickness combinations are conceivable here, which are applied according to the application. The layer system can therefore be designed and dimensioned in accordance with the requirements. The invention can thus be adapted to and optimized for various areas of application. In particular, despite the use of small layer thicknesses, highly efficient fire protection coatings can be created, which consequently have a low weight, which is particularly advantageous for many applications, for example in automobile construction.

Furthermore, the fire protection coating according to the invention can be applied to structured and / or contoured surfaces and flexibly adapted to these. Another advantage of the fire protection coating according to the invention is the very good operational strength properties, in particular since there is a material bond with the substrate (the carrier structure). This is shown, for example, in a very pronounced high resistance to vibrations, which is also essential for many purposes, for example in automobile construction.

Another aspect of the invention relates to a fire protection cover which is particularly suitable for use in a lithium-ion battery or a housing for such a battery. Here, a fire protection cover is understood to mean a cover or casing to prevent the spread (or reduce the probability of spreading) of a fire. A fire protection cover therefore has a fire-retardant effect.

This object is achieved by a fire protection cover according to the present invention, the fire protection coating according to the invention being applied to a carrier structure. The carrier structure can, for example, comprise metal (such as steel or aluminum) and / or ceramic and / or carbon fibers and / or plastic or consist entirely of one of these materials.

Typical support structures can be preformed plastic parts or metal parts that are completely or partially provided with a corresponding fire protection coating. Inside or outside surfaces can be completely or partially provided with the fire protection coating. In other versions, several materials can also be combined with one another. For example, a fire protection cover made of one material (e.g. aluminum or plastic or fiber-reinforced plastic) can be locally reinforced by another material (e.g. sheet steel inserts), which is connected to the cover itself using suitable joining processes. The actual fire protection coating can then in turn be applied to the inside of the fire protection cover and ensure the thermal insulation effect with respect to the actual support structure. The materials can, for example, also be made via clinch connections, which are particularly suitable for connections between different metals, for example steel-aluminum.

There are also designs in which the fire protection coatings are arranged between the two cover materials, so that a sandwich is formed from the first material (for example steel on the inside) of the fire protection coating and an aluminum structure on the outside. So-called clinch connections are also conceivable here. This means that the fire protection coating would be particularly well protected mechanically by the steel structures on the inside.

In particular, it is particularly advantageous to use such a fire protection cover where a particularly high risk of fire or heat build-up exists or can arise. In particular, a battery cover (for example the cover of an individual cell module of a battery for an electric car or the cover of the housing of the entire battery), a wall of a housing for a battery or a cell module or a partition between the individual battery cells or accumulator cells can be such a fire protection cover be or include one. For example, the fire protection coating can be applied flat on the inside of a battery cover. The carrier structure of a battery cover used in automobile construction often consists of deep-drawn (contoured) aluminum or sheet steel components. As already explained above, a fire protection coating according to the invention can also be applied to such structures.

Another aspect relates to a housing for a battery (battery housing), in particular one Lithium-ion accumulator, which comprises a battery cover and / or a base body (housing trough), each of which is provided with such a fire protection cover. In comparison to known battery housings, such a battery housing has proven to be particularly safe for preventing the effects of thermal runaway. In an electric vehicle, battery housings, trays or lids are often found in structural components of the vehicle's floor pan that are often relevant to rigidity and strength. These important structural properties are not impaired by a fire protection coating according to the invention, but rather are largely retained in the event of thermal battery damage.

• das Bereitstellen einer Trägerstruktur, beispielsweise beinhaltend Metall, insbesondere Stahl oder
• Aluminium, und/oder Keramik und/oder Kohlenstofffasern und/oder Kunststoff oder vollständig bestehend aus einem dieser Materialien
• das Aufbringen einer ersten Epoxidharzlage auf die Trägerstruktur
• das Aufbringen einer ersten Keramikfaserlage auf die Epoxidharzlage.

Furthermore, the present invention is based on the object of specifying a method with which a fire protection cover can be produced with a fire protection coating according to the invention. According to the invention, this method comprises the following steps:

• the provision of a support structure, for example containing metal, in particular steel or
• Aluminum, and / or ceramic and / or carbon fibers and / or plastic or consisting entirely of one of these materials
• applying a first epoxy resin layer to the support structure
• applying a first ceramic fiber layer to the epoxy resin layer.

In a particular embodiment, this method comprises the step of applying a further or more further, for example two further, epoxy resin layers and / or one or more further, for example two further, ceramic fiber layers. This ensures that the fire protection cover produced is particularly effective. This can be further increased by alternately applying epoxy resin layers and ceramic fiber layers.

• Ausführungsform 1: Verfahren zur Herstellung einer Brandschutzabdeckung umfassend
• das Bereitstellen einer Trägerstruktur
• das Aufbringen einer ersten Epoxidharzlage auf die Trägerstruktur
• das Aufbringen einer ersten Keramikfaserlage auf die Epoxidharzlage.
• Ausführungsform 2: Verfahren nach Ausführungsform 1, umfassend
• das Aufbringen einer zweiten Epoxidharzlage und/oder einer zweiten Keramikfaserlage.
• Ausführungsform 3: Verfahren nach Ausführungsform 2, umfassend
• das Aufbringen einer dritten Epoxidharzlage und/oder einer dritten Keramikfaserlage.

In the following, various forms of a possible manufacturing process are listed purely by way of example:

• Embodiment 1: comprising a method for producing a fire protection cover
• the provision of a support structure
• applying a first epoxy resin layer to the support structure
• applying a first ceramic fiber layer to the epoxy resin layer.
• Embodiment 2: The method of Embodiment 1 comprising
• applying a second epoxy resin layer and / or a second ceramic fiber layer.
• Embodiment 3: The method of Embodiment 2 comprising
• the application of a third epoxy resin layer and / or a third ceramic fiber layer.

Embodiment 4: Method according to one of Embodiments 2 or 3, the application of the epoxy resin layers and the ceramic fiber layers taking place alternately.

Embodiment 5: The method according to one of embodiments 1 to 4, wherein the carrier structure consists of metal and / or ceramic and / or carbon fibers and / or plastic.

Embodiment 6: The method according to embodiment 5, wherein the support structure consists of aluminum and / or steel.

Embodiment 7: The method according to one of embodiments 1 to 6, wherein the fire protection cover is a battery cover or a wall of a housing for a battery, the battery being in particular a lithium-ion accumulator.

Coming back to 1 , this illustrates a first embodiment.

1 shows the typical structure of a housing in a greatly simplified form 100 for one battery 160 with a fire protection cover according to the invention 110 . The case 100 comprises a base body 150 (a housing tray) and a battery cover 140 and encloses a battery 160 , for example a lithium-ion battery. The fire protection cover 110 serves as a battery cover 140 and consists of the support structure 130 as well as a fire protection coating 120 . Embodiments for such a fire protection coating are in the 2a and 2 B shown. Such a case 100 for a battery can for example be used in a vehicle with an electric drive, for example in electric cars. Through the fire protection cover 110 a fire, caused by thermal runaway, is prevented from spreading to the rest of the vehicle.

2a shows a first exemplary embodiment for a fire protection cover according to the invention in a likewise greatly simplified form 110 as they are for a battery cover, for example 140 , but can also be used in other places, for example in the form of a wall of a housing or a pipe. The one shown Fire protection cover 110 includes a support structure 130 as well as a fire protection coating 120 consisting of two layers, namely an epoxy resin layer 210 and a ceramic fiber layer 220 .

2 B shows (again greatly simplified) a second exemplary embodiment - a more complex variant - of a fire protection cover according to the invention 110 : In this case, are on the support structure 130 three epoxy resin layers each 220 and ceramic fiber layers 210 applied, which alternate. Compared to the fire protection cover 2a an even further improved fire protection is achieved in this way.

2c shows a third embodiment of a fire protection cover 410 , which, as a deep-drawn aluminum component, forms a cover that is attached to areas that are particularly exposed to heat 411 a multilayer fire protection coating according to the invention 420 having. The fire protection coating 420 is designed in such a way that it fills the embossed areas (beads, depressions) of the fire protection cover and follows their surface courses and contours. This is ensured by first applying an epoxy resin layer, then introducing / pressing one or more ceramic fiber layers into the still moist epoxy resin layer and finally applying another epoxy resin layer to the flexible molded-in ceramic fiber layer.

2d shows a fourth embodiment of a fire protection cover 510 , in which a multi-layer support structure 530 is provided which consists of an outer aluminum structure 531 and internal steel structures 532 (Steel inserts) that are clinched together. In the embodiment shown is on the inner surfaces of the steel structures 532 the fire protection coating according to the invention 520 applied.

2e shows an alternative embodiment (fifth embodiment) in which the fire protection coating 520 between the aluminum component 531 and the steel insert 532 is arranged and is also fixed by the clinch points. With such an embodiment, clinching can also be dispensed with, in that the insulating coating is used for a material connection between the outer aluminum component 431 and the inner steel insert 532 and these are glued together. In such an embodiment, the epoxy layer can, for example, first 520 on the inside of the aluminum component 531 are applied, then a ceramic fiber layer is applied 510 applied and the second epoxy resin layer 520 on the ceramic fiber layer 510 applied and finally the steel component is applied 532 on the inner epoxy resin layer 520 upset. This creates a kind of adhesive bond between the aluminum component 531 and the steel insert 532 one by placing these components over the fire protection coating 520 be connected to each other. Instead of the steel / aluminum material pairing, such a structure can also be implemented with other material combinations (e.g. metal-metal, plastic-plastic, metal-plastic).

3 shows a flowchart showing an example of a possible method for producing a fire protection cover. First is in step 310 a support structure is provided, for example a metal sheet, the wall of a housing or a pipe. This support structure can consist of a wide variety of materials, for example plastic or metal. Then takes place in step 320 applying a first epoxy resin layer to the support structure. The epoxy resin coating material (and any hardener that may be required) can be applied, for example, with one or more nozzle heads. This layer is applied (if necessary after a necessary drying and / or hardening process) in step 320 a ceramic fiber layer is applied to the epoxy resin layer. If desired, these last two procedural steps can be repeated several times in succession (arrow 350 ) to create alternating layers of epoxy resin / ceramic fiber. As soon as the desired number of layers has been reached, it is conceivable that the last layer applied is still in step 340 is provided with a final layer of a further material, for example a lacquer. This could further increase the chemical and / or mechanical resistance of the system. It is also conceivable that between and / or parallel to these steps and / or at the end 340 Further steps must be carried out in the manufacturing process. These additional steps could include, for example, quality assurance checks such as visual inspections or layer thickness measurements, steps to mask individual areas or drying and curing steps. Layer thickness measurements could, for example, be carried out optically (for example using cameras or sensors) or analytically (i.e. based on information about the application process; for example, the layer thickness can be calculated from the relative position of the nozzle head for applying the epoxy resin and the amount applied) and optionally also carried out automatically . The layer thicknesses could be defined for certain layers by user specifications before the production process is carried out. It is also conceivable that, in addition to epoxy resin layers and ceramic fiber layers, further layers are applied, as already mentioned above, for example a final lacquer layer in order to increase the corrosion resistance or also additional layers between epoxy resin layers and ceramic fiber layers or between the support structure and the fire protection coating. These additional layers could also be applied only in locally limited areas of the carrier structure. For example, it is conceivable to apply a layer of sealing material in areas particularly at risk of corrosion, such as in the area of welding studs, in order to further increase the corrosion resistance. For the sake of clarity, such additional steps are not shown in the figure and are to be understood as purely optional.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10208277 A1 [0003]
• DE 10238945 A1 [0003]

Claims (9)

Comprising a fire protection coating (120) for a battery arrangement of an electric vehicle an epoxy resin layer (210) and a ceramic fiber sheet (220). Fire protection coating (120) after Claim 1 , wherein the fire protection coating (120) comprises two epoxy resin layers (210) and / or two ceramic fiber layers (220). Fire protection coating (120) after Claim 2 wherein the fire protection coating (120) comprises three epoxy resin layers (210) and / or two ceramic fiber layers (220). Fire protection coating (120) according to one of the Claims 2 or 3 , wherein epoxy resin layers (210) and ceramic fiber layers (220) occur alternately in the fire protection coating (120). Fire protection cover (110) comprising a support structure (130) on which a fire protection coating (120) according to one of the Claims 1 until 4th is upset. Fire protection cover (110) Claim 5 , wherein the support structure (130) consists of metal and / or ceramic and / or carbon fibers and / or plastic. Fire protection cover (110) Claim 6 , wherein the support structure (130) consists of aluminum and / or steel. Fire protection cover (110) according to one of the Claims 5 until 7th wherein the fire protection cover (110) is a battery cover (140) or a wall of a housing (100) for a battery (160), the battery being in particular a lithium-ion accumulator. Housing (100) for a battery (160), in particular a lithium-ion accumulator, containing a base body (150) and a battery cover (140), the battery cover (140) and / or the base body (150) having a fire protection coating (120) ) after one of the Claims 1 until 4th includes.

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