High-voltage batteries for electrically operated vehicles

Abstract

The present invention relates to a high-voltage battery for an electrically operated vehicle, in which a certain number of unit modules are arranged in the battery housing, and the upper side of the unit modules is separated from the housing cover of the battery housing via an assembly gap inside the battery in the vertical direction of the housing, wherein in the case of a hot battery cell event, gas flows out of the battery cell of one of the unit modules and can be guided to the emergency venting outlet of the battery housing via the assembly gap inside the battery. According to the present invention, a certain number of heat-proof material blanks separated from each other are arranged in the assembly gap inside the battery between the upper side of the unit module and the housing cover, each of which is respectively associated with a unit module. Each heat-proof material blank has at least one elastically flexible extrusion element, which presses the heat-proof material blank onto the upper side of the unit module with an extrusion force during pressing.

Description

Technical Field

[0001] The present invention relates to a high-voltage battery (Hochvoltbatterie) for an electrically operated vehicle, in which a certain number of unit modules are arranged in the battery housing, and the upper sides of the unit modules are separated from the housing cover of the battery housing in the vertical direction of the housing via an assembly gap inside the battery, wherein, in the event of a hot battery cell event, gas flows out of the battery cell in one of the unit modules and can be guided to the emergency venting outlet of the battery housing via the assembly gap inside the battery. Background Art

[0002] A high-voltage battery installed in an electrically operated vehicle has a supporting battery housing in which a certain number of cell modules are arranged. A cell battery consisting of battery cells implemented as lithium-ion cells is arranged in the module housing of each cell module.

[0003] In this type of high-voltage battery, the cell modules are spaced apart from the housing cover of the battery housing at their cell module tops in the housing vertical direction via mounting gaps. In the event of a thermal event in the battery cells of the cell modules, fuel gas flows out, which is directed via the mounting gaps to emergency venting outlets of the battery housing.

[0004] In the prior art, structural measures are taken to maintain a sufficiently long evacuation duration (Evacuation-Zeitdauer) in such thermal events, during which the vehicle occupants can safely leave the vehicle. For example, the insulating material (Hitzeschutzmaterial) can be located in the housing interior space under the housing cover in the form of a large-area plate. The insulating material plate shields the battery housing from the gas coming out of the unit modules. However, the gas is directly guided through the adjacent, operational unit modules, whereby these unit modules are also heated up and exhausted. In addition, the large-area insulating material plate has a large structural space requirement, which hinders the gas flow in the assembly gap and thus leads to heat accumulation (Waermestau) in the housing interior space of the high-voltage battery. This also promotes the heating of the unit modules that are still operational.

[0005] A battery unit for a traction battery of a vehicle is known from WO 2018 / 108371 A1. A battery module with lithium-ion cells is known from JP 2 019 091 628A. Summary of the invention

[0006] The object of the present invention is to provide a high-voltage battery in which a sufficiently long evacuation duration can be provided in a structurally simple manner in the event of a thermal event in the high-voltage battery. Furthermore, damage to adjacent modules due to overheating should be prevented.

[0007] This object is achieved according to the present invention. Preferred improvements of the present invention are disclosed in the specification.

[0008] According to the invention, a number of heat protection material blanks separated from one another are arranged in the assembly gap between the upper side of the unit module and the housing cover. Each of the heat protection material blanks is respectively associated with exactly one unit module. In addition, each heat protection material blank has at least one elastically flexible pressing element, which presses the heat protection material blank against the upper side of the corresponding unit module (that is, the unit module cover) in a pressing manner with a predefined pressing force.

[0009] The heat-shielding material blank according to the present invention is designed to be significantly thinner-walled than the prior art. According to the present invention, the unit module is therefore protected by a thin-walled heat-shielding material blank on the unit module cover. Here, the heat-shielding material blank is pressed onto the unit module or tensioned there by an elastic material. For example, the heat-shielding material blank can be pressed downward from the top by means of the battery cover by means of an elastic material. In the case of a vented battery cell, the heat-insulating material is pressed upwards against the battery cover by the impact of the outflowing hot gas. As a result, the gas can escape from the battery and be guided to the emergency venting outlet in the battery housing via the assembly gap and escape from there to the outside. The remaining operable unit modules are not damaged here because the heat-shielding material blank is held in place there on the upper side of the corresponding unit module by means of an elastic material as before.

[0010] The invention enables a free gas flow from the exhausted battery element in the event of a thermal event. All other, still operable cell modules are thermally shielded by means of corresponding heat-protective material blanks. The protection according to the invention can be implemented in a significantly more space-saving manner than in the prior art and can be used for all battery types.

[0011] In a preferred embodiment, the elastically flexible extrusion element can be formed from a foam material. It is advantageous in terms of manufacturing technology if not only the extrusion element but also the liquid sealing material implemented as a sealing strip (Dichtraupe) between the housing cover and the housing bottom is made of the same material, for example, the foam material mentioned above. The extrusion element fastens the heat protection material blank and presses it onto the unit module. In the event of a thermal event in the battery cell, the outflowing gas squeezes the heat protection material blank against the extrusion force with an impact force (Impulskraft) in the direction of the housing cover (the heat protection material blank is lifted). As a result, the gas can escape into the assembly gap and be guided to the emergency venting outlet of the battery housing.

[0012] Preferably, the elastically flexible extrusion element can be supported between the housing cover and the heat protection material blank. In this case, the extrusion element is directly located in the assembly gap between the housing cover and the heat protection material blank.

[0013] For reasons of simple handling during assembly of the high-voltage battery, it is preferred if the elastically flexible press element is fixedly connected at its element bottom to the housing cover or to a corresponding heat protection blank. In contrast, the press element can rest without connection at its element top on the opposite heat protection blank or housing cover.

[0014] The extrusion elements may be distributed over the entire surface of the corresponding heat protection material blank if necessary. Alternatively, the extrusion elements can provide a significantly reduced extrusion surface compared to the surface of the heat protection material blank. In this case, a large number of extrusion elements spaced apart from each other can be positioned between the housing cover and the heat protection material blank.

[0015] In an alternative embodiment, the elastically flexible pressing element can be realized as at least one elastic tensioning band, with which the heat protection material blank can be fixed to the unit module. The tensioning band can apply a prestress to the heat protection material blank, by means of which the heat protection material blank is pressed against the upper side of the unit module with a pressing force.

[0016] The tensioning straps can be replaced by any type of elastic element. Additionally there is the possibility of fastening the insulation material with weaker glue or other fixing elements. In the event of a thermal event, the element tears or breaks.

[0017] The invention prevents the thermal event from spreading to adjacent, still functional unit modules, thereby significantly reducing the consequences for the vehicle and the environment. The hot gases generated in the thermal event are directed away, thereby reducing the heating of adjacent unit modules and prolonging the time for spreading to adjacent, still functional unit modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Next, embodiments of the present invention are described with reference to the accompanying drawings, in which:

[0019] Figure 1 The body structure of an electrically operated vehicle with a high-voltage battery installed therein is shown in a semi-sectioned view on the floor side.

[0020] Figure 1a The unit modules are shown separately.

[0021] Figure 2 shows an enlarged partial cross-sectional view of a high voltage battery,

[0022] Figure 3 Shows the corresponding Figure 2 A view of the thermal events, and

[0023] Figure 4 , 5 and 6 show the corresponding Figure 2 Implementation variants of the embodiment shown in . DETAILED DESCRIPTION

[0024] exist Figure 1 The floor-side body structure of a two-track vehicle is shown in a half-section view, which is explained below as necessary for understanding the invention. The floor-side body structure thus has two lateral sills 1 extending in the longitudinal direction of the vehicle, Figure 1 Only one of them is shown in Figure 1 The right vehicle half (not shown) is designed approximately in a mirror image of the left vehicle half shown. The door sill 1 extends in the longitudinal direction of the vehicle and forms a floor-side door entry area 2 for vehicle passengers. A high-voltage battery 5 is installed on its lower side in the vehicle floor 3 of the body structure. It extends in the vehicle transverse direction y in the installation space between the two door sills 1. The high-voltage battery 5 is located in the vehicle floor 3 of the body structure. Figure 1 The center is located at approximately the same height as the door sill 1.

[0025] As from Figure 1 As is further apparent, the high-voltage battery 5 has a battery housing which is constructed from a housing bottom part 7 and an upper housing cover 7 which is spaced apart from the vehicle floor 3 arranged above by means of an assembly gap 11 .

[0026] A number of cell modules 13 are arranged in the housing interior of the high-voltage battery 5. A cell group consisting of battery cells 15 implemented as lithium-ion cells is arranged in the module housing of each cell module 13. Figure 1 The battery housing is screwed to the base 19 of the battery housing at the screwing point 17 shown. Figure 1 and 2 In the embodiment, the unit module 13 is located at its upper side (that is, at the Figure 1 and 1a The cell module cover 35 of the battery housing is separated from the housing cover 9 of the battery housing by the assembly gap 21 inside the battery in the vertical direction z of the housing. Figure 1 and 2 In the embodiment, a certain number of heat protection material blanks 23 separated from each other are arranged in the assembly gap 21 inside the battery between the upper side 35 of the unit module and the housing cover 9. Each of the heat protection material blanks 23 is respectively associated with exactly one unit module 13. The heat protection material blank 23 also has an elastically flexible extrusion element 25. It is arranged according to Figure 1 and Figure 2In normal operation, the housing cover 9 is located uncompressed in the assembly gap 21 between the housing cover 9 and the top side of the cell module.

[0027] exist Figure 1 In the embodiment, the housing cover 9 is mounted on the housing bottom part 7 at the edge with the intermediate placement of a sealing strip 27 which acts as a liquid seal. Figure 1 and 2 Each unit module 13 is provided with two extruded elements 25 of reduced area compared to the corresponding heat protection material blank 23. Figure 1 and 2 The housing cover 27 is manufactured in a simple manner from a foam material, which is also used to produce the sealing strip 27 between the housing cover 9 and the housing bottom part 7 .

[0028] exist Figure 1 The extrusion element 25 shown in FIG. 2 has its element bottom 29 ( Figure 2 ) is connected (that is to say glued) to the housing cover 9. In contrast, the element top 31 of the extruded element 25 is not connected to the heat protection material blank 23.

[0029] Next, according to Figure 3 The function of the heat protection material blank 23 according to the invention in the event of a thermal event in a lithium-ion cell 15 is described below: In this case, the damaged cell 15 and the cell module top 35 open and hot gases and exothermic particles escape. The heat protection material blank 23 is pushed against the pressing force F by the outflowing gases or particles. A The reverse impact force is used to press upward in the direction of the housing cover 9, so that the gas together with the particles can escape into the assembly gap 21 inside the battery. From there, the gas or particles are discharged along the assembly gap 21 in the direction of the arrow A ( Figure 3 ) is guided to an emergency vent (not shown) of the battery housing. From there the gas escapes to the outside of the battery.

[0030] As Figure 3 As can be seen, the heat protection material blank 23 of the still operable adjacent unit module 13 remains unchanged pressed against the unit module upper side 35. The gas is therefore not guided directly through the unit module upper side 35 of the adjacent unit module 13 in the assembly gap 21, but with the heat protection material blank 23 placed in between. In this way, the thermal event T is prevented from spreading to the adjacent unit modules 13.

[0031] Next, according to Figures 4 to 6 To illustrate other implementation variations of the present invention. Figure 4 In the embodiment, the extruded element 25 is no longer connected to the housing cover 9 with its corresponding element bottom, but is fixedly connected to the corresponding heat protection material blank 23. In other aspects, Figure 4 The embodiment corresponds to Figure 2 Embodiment of the invention.

[0032] exist Figure 5 In the embodiment, a larger number of extruded elements 25 with a smaller area are not provided for each unit module 13. Figure 5 In this embodiment, only one elastically flexible extrusion element 25 is used for each unit module, which extends over the entire surface of the corresponding heat protection material blank 23 over the entire surface.

[0033] exist Figure 6 In the embodiment, the elastically flexible extrusion element 25 is no longer implemented as a compression element located between the housing cover 9 and the heat protection material blank 23, but is implemented as a tensioning belt. Figure 6 Independent of the housing cover 9, it is fixed directly to the side wall 33 of the unit module 13. By means of the tensioning band 25, a prestress is applied to the corresponding heat protection material blank 23, by means of which the pressing force F A The heat-proof material blank 23 is pressed toward the upper side of the unit module.

[0034] List of Reference Numerals

[0035] 1 Threshold

[0036] 2 Entrance area

[0037] 3 Vehicle floor

[0038] 5 High voltage battery

[0039] 7 Lower part of the housing

[0040] 9 Housing cover

[0041] 11 Assembly gap outside the battery

[0042] 13 unit modules

[0043] 15 Battery Cell

[0044] 17 Screw-on area

[0045] 19 Base

[0046] 21 Assembly gap inside the battery

[0047] 23 Heat-resistant material blank

[0048] 25 Extrusion element

[0049] 27 Sealing tape

[0050] 29 Component bottom

[0051] 31 Component top

[0052] 33 Unit module side wall

[0053] 35-unit module cover

[0054] E Longitudinal plane of vehicle center

[0055] T Thermal Event

[0056] F A Extrusion pressure.

Claims

1. A high-voltage battery, in which a certain number of unit modules (13) are arranged in a battery housing, wherein the upper side (35) of the unit modules is separated from the housing cover (9) of the battery housing via an assembly gap (21) inside the battery in the vertical direction of the housing, wherein: In the event of a hot battery cell event, gas flows out of a battery cell (15) in one of the unit modules (13) and can be guided to an emergency venting outlet of the battery housing via the assembly gap (21) inside the battery, characterized in that a certain number of heat-resistant material blanks (23) separated from each other are arranged in the assembly gap (21) inside the battery between the upper side (35) of the unit module and the housing cover (9), each of which is respectively associated with a unit module (13), and each heat-resistant material blank (23) has at least one elastically flexible extrusion element (25) which presses the heat-resistant material blank (23) onto the upper side (35) of the unit module with an extrusion force during pressing, wherein the elastically flexible extrusion element (25) is connected at its element bottom (29) to the housing cover (9) or to the corresponding heat-resistant material blank (23), and the extrusion element (25) is unconnected at its element top (31) relative to the heat-resistant material blank (23) or the housing cover (9).

2. The high-voltage battery according to claim 1, characterized in that: In normal operation, all heat protection material blanks (23) are in pressure contact with the upper side of the unit module.

3. The high voltage battery according to claim 2, characterized in that: The gas flowing out in the unit module (13) in the event of a thermal event presses the heat protection material blank (23) in the direction of the housing cover (9) with an impact force against the extrusion force, thereby escaping into the assembly gap (21) inside the battery, and the heat protection material blank (23) of the operable unit module (13) remains unchanged in pressure against the unit module upper side (35).

4. The high-voltage battery according to claim 1, characterized in that: The elastically flexible extrusion element (25) is supported between the housing cover (9) and the heat protection material blank (23).

5. The high voltage battery according to any one of claims 1 to 4, characterized in that: The elastically flexible pressing element (25) is formed from a foam material and / or the liquid seal (27) implemented as a sealing strip between the housing cover (9) and the housing bottom (7) and the pressing element (25) are made of the same material.

6. The high voltage battery according to any one of claims 1 to 4, characterized in that: The elastically flexible extrusion elements (25) are distributed over substantially the entire surface of the corresponding heat protection material blank (23), or the extrusion elements (25) provide a reduced extrusion surface compared to the surface of the heat protection material blank (23).

7. The high voltage battery according to any one of claims 1 to 4, characterized in that: The elastically flexible extrusion element (25) is a tensioning band, and the tensioning band is fixed to the unit module housing independently of the housing cover (9), and the tensioning band applies prestress to the heat protection material blank (23), and with the help of the prestress, the heat protection material blank (23) is pressed toward the upper side of the unit module with the extrusion force.

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