Battery and motor vehicle with fire protection device

Abstract

The invention relates to a battery (12) with a fire protection device, wherein the battery (12) has a battery housing (18) and a plurality of battery cells (14), wherein the respective battery cells (14) are arranged in the interior (16) of the battery housing (18). The fire protection device has a layer composite (22) with a thermal insulation layer (24) and a protective layer (26) arranged on the insulation layer (24), the layer composite being arranged on the inner side of the battery housing facing the interior (16) of the battery housing (18), wherein the insulation layer (24) is arranged as an intermediate layer between the surface of the inner side of the battery housing and the protective layer (26) and is protected by the protective layer (26) from gas jets and / or flame jets (28) escaping from the respective battery cells (14) in the event of damage, thereby maintaining the thermal insulation properties of the insulation layer.

Description

Technical Field

[0001] The invention relates to a battery with a fire protection device and a motor vehicle with such a battery. The battery according to the invention has a plurality of battery cells, wherein the respective battery cells are arranged in the interior space of a battery housing of the battery. Background Art

[0002] In the sense of the present invention, the battery is preferably a so-called high-voltage battery, i.e. a battery which is configured to provide a voltage in the range of more than 60 volts, in particular in the range of several hundred volts. Such a battery is preferably used in an at least partially electrically driven motor vehicle, in which the battery provides the electric drive energy for driving the motor vehicle. The high voltage required for this is achieved in the above-mentioned range by connecting the individual battery cells of the battery to one another in an electrically conductive manner. The individual battery cells preferably provide a voltage in the range between 3.5 volts and 4 volts, in particular a voltage of 3.6 volts. The corresponding energy density of such a battery cell is particularly influenced or limited by the corresponding battery chemistry of the battery cell. If a damage occurs in such a battery cell, or more precisely in the galvanic cell of such a battery cell, such as an internal short circuit, a gas mixture may accumulate inside the corresponding battery cell housing due to the chemical reaction caused thereby, the composition of the gas mixture depending on the corresponding battery chemistry. In addition, such a chemical reaction caused by the damage usually leads to a strong heating of the corresponding battery cell compared to the standard temperature range or standard operating temperature of the battery cell.

[0003] Various approaches are known from the prior art to thermally insulate such heated, damaged battery cells. For this purpose, WO 2017 / 139826 A1 and DE 10 2012 222 876 A1 each provide a thermally insulating coating of the battery cells, which is at least partially composed of a foamable material, i.e., a material that can be foamed by the action of heat. For this purpose, the foamable coating at least partially surrounds the battery composite or battery pack, or is arranged as a thermal insulation layer between the individual battery cells.

[0004] Document DE 10 2016 100 223 A1 also describes a fireproof material which can be used in vehicle batteries and can serve as a heat source.

[0005] Finally, document DE 10 2012 019 676 A1 discloses a battery transport container with a flexible jacket. The battery transport container has a hose-shaped exhaust pipe formed by multiple layers. One of the layers includes a heat-resistant fabric, and another layer includes, for example, an expansion material or a foaming material. As mentioned at the beginning, gas accumulation or gas generation may occur in damaged battery cells. Due to gas generation, a battery cell internal pressure higher than the specified operating pressure is established inside the damaged battery cell, which may cause gas to escape from the battery cell in the form of a gas jet and / or a flame jet. Although the known and described solutions can achieve effective thermal insulation of the damaged battery cell or the entire battery pack, for the described situation where the gas jet and / or flame jet escapes from the battery cell housing of the damaged battery cell into the inner space or the interior of the battery housing surrounding the corresponding battery cell, no other, especially mechanical, protective measures are provided. Summary of the invention

[0006] The object of the present invention is to provide an improved fire protection device for a battery of the type mentioned at the outset. In particular, a fire protection is to be achieved which, as described above, even in the event of the escape of gas jets and / or flame jets caused by damage, enables effective thermal insulation of the damaged battery cell(s) and thus maintains the integrity of the battery housing at least for a predetermined time period after the occurrence of the damage.

[0007] This object is achieved by the subject matter of the independent claims. Advantageous developments of the invention are described by the dependent claims, the following description and the drawings.

[0008] The invention is based on the recognition that layers made of foamed material, although providing effective thermal insulation, have no or only low resistance to mechanical loads, in particular to the escape of gas jets and / or flame jets caused by damage, such layers have no or only low mechanical resistance.

[0009] The present invention provides a battery with a fire protection device. According to the above manner, the battery includes a plurality of battery cells and a battery housing. Here, the respective battery cells are arranged in the inner space of the battery housing. In other words, the respective battery housing surrounds or encloses the plurality of battery cells. In other words, the battery cells are separated by the battery housing from the surrounding environment or external area surrounding the battery housing or adjacent to the battery housing. Preferably, the battery housing is sealed or hermetically closed. The battery housing is preferably made of metal, in particular aluminum.

[0010] The fire protection device according to the present invention has a layer composite structure / laminated structure (Schichtverbund), which has a thermal insulation layer and a protective layer arranged on the insulation layer. The layer composite structure can be designed in the form of a mat, for example. According to the present invention, the layer composite structure is arranged on the inner side of the battery housing facing the inner space of the battery housing. According to the present invention, the insulation layer is arranged as an intermediate layer between the surface of the inner side of the battery housing and the protective layer. In other words, the fire protection device according to the present invention has a stack or stacked layer sequence formed by the insulation layer and the protective layer. The insulation layer is designed as an intermediate layer arranged between the surface of the inner side of the battery housing and the protective layer, and this arrangement of the insulation layer and the protective layer according to the present invention leads in an advantageous manner to the insulation layer being protected by the protective layer against gas beams and / or flame beams escaping from the corresponding battery cells in the event of damage. The thermal insulation properties of the insulation layer are thereby maintained in an advantageous manner.

[0011] The invention thus provides the advantage that the thermal insulation layer is mechanically protected from the gas jet and / or flame jet. It is thus advantageously avoided that the gas jet and / or flame jet destroys or burns through or penetrates the thermal insulation layer and thus disturbs its thermal insulation properties. The "damage case" mentioned here is therefore characterized in particular by the gas jet and / or flame jet escaping from at least one battery cell. The invention also includes a number of embodiments that produce additional advantages.

[0012] An advantageous embodiment provides that the respective battery cell has a predetermined breakdown site, which is arranged on the side of the battery cell facing the layer composite. Preferably, in the event of damage, the gas jet and / or flame jet first escapes from at least one predetermined breakdown site and hits the layer composite. Such a breakdown site can be fixed by means of a so-called rupture disc. In other words, the respective battery cell preferably has a defined weak point or a set fracture site, which yields before other areas of the respective battery cell housing break or yield under the increased battery cell internal pressure caused by the damage. As a result, the escape of the gas jet and / or flame jet caused by the damage can be guided in an advantageous manner. In other words, the corresponding site on the battery cell housing where the gas jet and / or flame jet escapes is known. According to the embodiment described here, the site (or the predetermined breakdown site) is arranged relative to the layer composite so that the escaping gas jet and / or flame jet hits the layer composite. Therefore, the layer composite does not have to be arranged in a manner covering the entire surface along the surface of the inner side of the battery housing, but can be arranged only partially in an advantageous and demand-oriented manner. Thus, the corresponding area is opposite the corresponding penetration point. This can advantageously save material and / or weight of the layer composite.

[0013] Depending on the corresponding battery chemistry, gas beams and / or flame beams can transport particles. Such particles usually have a diameter of less than 1 mm. Gas beams and / or flame beams carrying such particles can act like sandblasting and have a large mechanical damage potential accordingly. In order to prevent gas beams and / or flame beams and / or particles transported in gas beams and / or flame beams from being distributed in the inner space of the battery housing, a preferred improvement of the present invention stipulates that the gas beams and / or flame beams are turned toward the collection container of the fire protection device. According to the embodiment described here, the pressure drop in the inner space of the battery housing and / or the shape and / or orientation of the surface are designed to be used to turn the gas beam and / or flame beam along a predetermined path. For example, the turning can be achieved by rib-shaped protrusions and / or grooves formed along the surface. For the case where the collection container is located outside the battery housing, a pressure drop can be advantageously formed between the inner space and the collection container, and the pressure drop advantageously supports the turning. The pressure drop is generated, for example, by the battery housing being opened due to damage and no longer sealed airtightly. According to the embodiment described here, the layer composite structure is arranged along a predetermined path. In other words, the layer composite is arranged at the following points of the surface, where the gas jet and / or flame jet impinges on or flows along these points. Such points or critical points can be located, for example, at the curvature of the surface. By arranging the layer composite in such a targeted manner at the corresponding critical points, it is advantageously possible to avoid redundant or excessive application of the layer composite. In other words, according to these measures, on the one hand, the gas jet and / or flame jet is deflected along a predetermined path and on the other hand, the layer composite is arranged along this path, and these measures act together in a synergistic manner.

[0014] According to an advantageous development, the insulating layer is formed from a foaming material. In other words, the insulating layer is formed from a heat source material. Preferably, the temperatures occurring in the event of damage cause a foaming-induced volume increase of the insulating layer. Advantageously, therefore, by selecting the material of the insulating layer, it is ensured that the volume increase is only triggered at the temperatures caused by the damage. The insulating layer can be formed at least partially from epoxides or polymers. Foaming materials are sufficiently known to those skilled in the art and can be selected by them as required.

[0015] Preferably, the protective layer is formed by glass fiber fabric and / or metal nonwoven fabric (Gelege) or knitted fabric and / or by metal foil. Advantageously, the protective layer follows the shape of the foamed layer when expanding, but does not hinder expansion. At the same time, the protective layer produces the mechanical protection effect described on the insulating layer. In other words, the foamed insulating layer and the protective layer described here act synergistically in the layer composite structure. The protective layer or fiber layer or foil layer therefore protects the foamed material, which in turn protects the battery housing from the influence of the temperature caused by the damage situation. As mentioned at the beginning, the battery housing can preferably be made of aluminum. It is known that aluminum loses its inherent strength from a temperature of about 240 degrees Celsius. It is known that aluminum begins to melt at about 660 degrees Celsius. Therefore, the layer composite structure is preferably designed to limit the battery housing temperature to a maximum of 240 degrees Celsius in order to maintain the inherent strength of the aluminum housing.

[0016] The protective layer is preferably formed from a fine-meshed glass fiber fabric, wherein the roughness of the protective layer is preferably selected so that the above-mentioned particles cannot adhere. In other words, the protective layer is preferably designed so that the elevations and depressions, in particular microscopic elevations, have a diameter or radius along the surface of the protective layer that is correspondingly lower than the average particle diameter. This is preferably achieved by using the aforementioned metal foil.

[0017] According to an advantageous embodiment, the protective layer is integrated into the material of the insulating layer. For example, the protective layer can be designed as a glass fiber fabric, which can be pressed into the surface of the insulating layer. In other words, the glass fiber fabric can be pressed onto the insulating layer so that the material of the insulating layer at least partially penetrates the meshes or holes of the glass fiber fabric. This results in the advantage of a simplified assembly of the layer composite, since no separate processing of the layers is required.

[0018] Preferably, the insulating layer has a thickness of 0.5 mm to 1 mm, in particular a thickness of 0.6 mm.

[0019] The gas jet and / or flame jet typically has a temperature of 600 to 1100 degrees Celsius, in particular 840 degrees Celsius, which is influenced by the battery chemistry and caused by damage.

[0020] In the event of damage, the internal pressure of the battery cell usually has a value of five to ten bar, in particular a value of eight bar, wherein when the internal pressure of the battery cell caused by the damage is reached, the predetermined breakdown point ruptures. As described above, the layer composite is arranged spatially at least relative to the breakdown point or at least in a region opposite the breakdown point. Alternatively, it can be provided that the insulating layer of the layer composite completely envelops the battery housing, wherein only the protective layer is arranged in the region of the respective breakdown point.

[0021] Furthermore, the invention relates to a motor vehicle having a battery.

[0022] The invention also includes improvements of the motor vehicle according to the invention, which have the features already described in conjunction with the improvements of the battery according to the invention. For this reason, the corresponding improvements of the motor vehicle according to the invention will not be described here.

[0023] The motor vehicle according to the invention is preferably designed as a car, in particular a passenger car or a truck, or as a bus or a motorcycle.

[0024] The invention also includes combinations of features of the described embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following describes an embodiment of the present invention. To this end, the only accompanying drawing ( Figure 1 ) shows a schematic diagram of a motor vehicle with a battery.

[0026] The embodiments described below are preferred embodiments of the present invention. In the embodiments, the described parts of the embodiments are the features of the present invention that can be viewed independently of each other, and these features also improve the present invention independently of each other. Therefore, the present disclosure should also include other combinations different from the shown combinations of the features of the embodiments. In addition, the embodiments can also be supplemented by other features in the features already described of the present invention.

[0027] In the figures, the same reference numerals respectively denote elements with the same function. DETAILED DESCRIPTION

[0028] Figure 1 A schematic diagram of a motor vehicle 10 is shown with a battery 12. The battery 12 shown in the figure has, by way of example, four battery cells 14. The battery cells 14 are arranged in an interior space 16 of a battery housing 18 of the battery 12. The respective battery cell 14 has a predetermined puncture point 20. In the exemplary embodiment shown in the figure, the respective puncture point 20 is arranged on the side of the respective battery cell 14 facing the layer composite 22. Figure 1 The layer composite structure 22 in FIG. 2 includes an insulating layer 24 and a protective layer 26 .

[0029] exist Figure 1, a damage situation occurs in the battery cell 14 arranged on the far left. Accordingly, as described above, gas generation occurs in this battery cell 14. The resulting increased internal cell pressure of the battery cell 14 leads to a rupture of the breakdown site 20. As a result, a flame jet and / or a gas jet 28 escapes from the breakdown site 20 according to the arrows shown in the figure. As described, the protective layer 26 protects the insulating layer 24 from the mechanical effects of the escaping gas jet and / or flame jet 28, so that the thermal insulation properties of the insulating layer 24 of the layer composite 22 remain unchanged.

[0030] The coating or layer composite 22 is therefore preferably formed by a combination of a foamed fireproof coating or insulation layer 24 and an additional fabric layer or protective layer 26, in particular a glass fiber fabric. The fabric layer has the function of braking the escaping gas jet and / or flame jet 28 in the event of damage, thereby advantageously avoiding damage to the fireproof coating or insulation layer 24. In other words, the foamed fireproof coating ensures the fireproof properties of the layer composite 22 despite the escape of gas jets and / or flame jets 28.

[0031] Overall, the exemplary embodiments show how an extended fire protection coating can be provided by means of the present invention.

Claims

1. A battery (12) having a fire protection device, wherein: The battery (12) comprises a battery housing (18) and a plurality of battery cells (14), wherein each battery cell (14) is arranged in an interior space (16) of the battery housing (18). It is characterized in that The fire protection device comprises a layer composite (22) having a thermal insulation layer (24) and a protective layer (26) arranged on the insulation layer (24), wherein the layer composite is arranged on the inner side of the battery housing facing the inner space (16) of the battery housing (18), the insulation layer (24) being arranged as an intermediate layer between the surface of the inner side of the battery housing and the protective layer (26), the insulation layer being protected by the protective layer (26) from gas jets and / or flame jets (28) escaping from the corresponding battery cells (14) in the event of damage, thereby maintaining the thermal insulation properties of the insulation layer, The respective battery cell (14) has a predetermined penetration point (20) which is arranged on the side of the battery cell (14) facing the layer composite (22), wherein in the event of damage, a gas jet and / or a flame jet (28) first escapes from at least one predetermined penetration point (20) and impinges on the layer composite (22), The pressure drop in the interior space (16) and / or the shape and / or orientation of the surface are designed to divert the gas jet and / or flame jet (28) along a predetermined path, wherein the fire protection device has a collecting container for collecting the gas jet and / or flame jet (28) diverted toward the collecting container and / or particles transported in the gas jet and / or flame jet (28), and the layer composite structure (22) is arranged along the path.

2. The battery (12) according to claim 1, characterized in that The insulating layer (24) is formed from a foamed material, wherein the temperatures occurring in the event of damage cause an increase in volume of the insulating layer (24) due to foaming.

3. The battery (12) according to claim 1 or 2, characterized in that: The protective layer (26) is formed from a glass fiber fabric and / or a metal nonwoven fabric or knitted fabric and / or from a metal foil.

4. The battery (12) according to claim 1 or 2, characterized in that: The protective layer (26) is integrated into the material of the insulating layer (24).

5. The battery (12) according to claim 1 or 2, characterized in that: The insulating layer (24) has a thickness of 0.5 mm to 1 mm.

6. The battery (12) according to claim 1 or 2, characterized in that: The gas and / or flame beam (28) has a temperature of 600 degrees Celsius to 1100 degrees Celsius, determined by the battery chemistry.

7. The battery (12) according to claim 1 or 2, characterized in that: In the event of damage, the internal cell pressure has a value of five bar to ten bar, wherein the predetermined breakdown point (20) ruptures when the internal cell pressure caused by the damage is reached.

8. The battery (12) according to claim 5, characterized in that The insulating layer (24) has a thickness of 0.6 mm.

9. The battery (12) according to claim 6, characterized in that The gas and / or flame beam (28) has a temperature of 840 degrees Celsius.

10. The battery (12) according to claim 7, characterized in that In the event of damage, the internal pressure of the battery cell has a value of eight bar.

11. A motor vehicle (10) comprising a battery (12) according to any one of claims 1 to 10.

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