Underbody element for a traction battery of a motor vehicle, motor vehicle with an underbody element and method for determining an intrusion of a traction battery of a motor vehicle

Description

[0001] The invention relates to an underbody element for a traction battery of a motor vehicle, which comprises at least one sensor device, a motor vehicle with such an underbody element and a method for detecting an intrusion of a traction battery of a motor vehicle.

[0002] Nowadays, many motor vehicles are partially or fully electric, for example as hybrid vehicles or as purely electric vehicles. The drive battery or traction battery required for this, which usually comprises several battery cells, is usually located in a floor area of ​​the vehicle. This has the disadvantage that impacts from below impinge directly on the traction battery, which can lead to damage to the traction battery. In order to limit or prevent damage caused by intrusion from below, it is known to use an underbody element for the traction battery, which can be designed, for example, as an underrun guard to protect the traction battery from direct force. The underbody element can be a panel on the underbody of the traction battery and / or the motor vehicle, which shields the traction battery from environmental influences and / or mechanical influences.

[0003] However, even an underbody element does not protect the traction battery from all impacts, and strong impacts from below, for example when the vehicle bottoms out while driving over a bollard, can cause the underbody element to be pushed into the traction battery, causing damage to the traction battery. This means that an intrusion of the traction battery can occur. In order to identify this type of damage and minimize consequential damage to the vehicle and / or danger to the driver, these events must be detected in order to draw conclusions as to whether the battery cells of the traction battery have experienced an intrusion. This means that a sensing concept is required to detect physical penetration or deformation of the traction battery.

[0004] EP 1 168 463 A1 discloses a fiber composite material with an integrated piezoelectric sensor or actuator. The electrical leads for the actuator or sensor are designed as electrically insulated, thin wires that extend perpendicular to the laminate layers from the fiber composite material. The fibers are not severed by the extension of the leads, but rather pushed apart.

[0005] The invention is based on the object of detecting damage to a traction battery originating from underneath the motor vehicle.

[0006] This object is achieved by the independent patent claims. Advantageous developments of the invention are disclosed in the dependent patent claims, the following description, and the figures.

[0007] The invention provides an underbody element for a traction battery of a motor vehicle, comprising at least one sensor device. The term "underbody element" refers to a floor panel, in particular an underride guard, which, in a proper installation position in the motor vehicle, is arranged toward an underside of the motor vehicle and / or the traction battery and which provides at least a protective effect against external influences. According to the invention, the underbody element has at least one sensor device, wherein the sensor device has at least one electrically conductive sensor wire integrated into a flat textile material, wherein the sensor device is designed to measure a voltage applied to the sensor wire and to detect a deformation of the sensor wire depending on a measured change in the voltage.

[0008] In other words, at least one electrically conductive sensor wire is integrated into a flat textile material. For example, the wire material can be applied to a flat textile semi-finished product. The textile material can serve as a support structure that can facilitate attachment of the sensor wire to the underbody element. Thus, for example, the textile material can be attached to the underbody element over a large area, so that the sensor wire is evenly distributed over the underbody element and covers a large part of the underbody element. The textile material can, for example, be designed as a fiber composite material, which can increase strength.The sensor wire, which can be made of metal, for example, can be passed through by a current at a predetermined voltage during operation. A deformation of the sensor wire leads to a change in the voltage. Thus, if a change is detected, the deformation of the underbody element and, consequently, an intrusion onto a traction battery of the motor vehicle can be detected. The invention offers the advantage that a deformation, in particular a deformation of the underbody element, can be detected in a simple manner. The deformation of the underbody element can be used to infer damage to the traction battery.

[0009] The invention also includes embodiments which provide additional advantages.

[0010] One embodiment provides for the sensor wire to be integrated into the flat textile material in a meandering pattern. In other words, the sensor wire can run in a loop-like manner across a predetermined width of the textile material. This provides the advantage that the sensor wire covers a large area of ​​the textile material while saving sensor wire material, thus providing improved sensing of deformations.

[0011] Preferably, the sensor wire is made of carbon fiber or a metal-coated plastic filament. In other words, the sensor wire can be formed as carbon fiber or carbon fiber that is incorporated into the flat textile material. The advantage of carbon is its very good electrical conductivity and, at the same time, an improved option for integrating the sensor wire into the textile material. Furthermore, the carbon fiber can be used to reinforce a structure of the underbody element. In particular, carbon can be processed as a fiber composite material. Alternatively, the sensor wire can be formed as a plastic filament that is coated with a metal. The advantage of a plastic filament is that it can be incorporated into the textile material particularly easily, which simplifies production and saves costs.The conductivity of the sensor wire is provided by the metal coating. In another alternative, the sensor wire can be made of a metal, particularly copper, which can be cost-effectively incorporated into the textile material.

[0012] A further embodiment provides that the sensor wire is designed to change an electrical resistance upon deformation. This means that the change in voltage and thus the deformation of the sensor wire are detected by the sensor wire changing its electrical resistance. If the underbody element deforms, the length and / or diameter of the sensor wire changes, leading to a measurable change in resistance. The sensor wire can therefore preferably be made of suitable materials, in particular carbon, which changes the length and thickness of the sensor wire upon deformation. Alternatively, the sensor wire can also break if the deformation is too great, in which case the change in voltage can be detected if no current is flowing through the sensor wire.

[0013] A further embodiment provides that the sensor device is configured to generate a warning signal if the measured change in voltage exceeds a predefined voltage threshold. In other words, the sensor device can determine the magnitude of the change in voltage. If the change exceeds a predefined voltage threshold, a warning signal can be generated. The warning signal can preferably be used to warn a driver of the motor vehicle. For example, the warning signal can serve as a control signal for an indicator light that can indicate damage to the traction battery to the driver of the motor vehicle.The sensor device can also have electronics or an evaluation unit that measures and evaluates the voltage. Depending on the measured change in voltage, several voltage threshold values ​​can be provided, which can indicate different degrees of severity of intrusions on the traction battery of the motor vehicle. In particular, the change in voltage can be dependent on the deformation of the sensor wire, whereby the warning signal can be provided depending on the change in voltage. This embodiment offers the advantage that damage to the traction battery and / or deformation of the sensor wire is only recognized as such above a certain threshold, and minor impacts that do not cause damage can be avoided as false detection.

[0014] One embodiment provides that, during proper installation of the underbody element, the flat textile material with the sensor wire is arranged on a surface of the underbody element facing the motor vehicle. In particular, the flat textile material can be glued to the surface of the underbody element. To bond the textile material to the surface of the underbody element, the textile material or semi-finished textile can be previously injected with resin and thus attached to the surface as a thin plate. This results in a preferred form of attachment of the sensor device to the underbody element.

[0015] A further embodiment provides that the underbody element has a foam insert as a rigid intermediate layer between at least two cover layers, wherein the flat textile material with the sensor wire is arranged between the foam insert and one of the two cover layers. In other words, a different construction of the underbody element can provide that the textile material is arranged between one of two cover layers and an intermediate layer designed as a foam insert. Thus, the textile material or semi-finished textile product can be directly integrated into the manufacturing process of the underbody element. The cover layers can preferably be formed from a glass fiber fabric, whereby an additional protective effect can be provided. This embodiment can provide a further preferred form of attachment of the sensor device in the underbody element.

[0016] In a further embodiment, the underbody element comprises a foam insert as a rigid intermediate layer between at least two cover layers, wherein the flat textile material with the sensor wire is integrated into the foam insert. In other words, the underbody element can be designed in a similar manner to the aforementioned embodiment, i.e., with two cover layers enclosing a foam insert between them, wherein the textile material with the sensor wire can be foamed into the foam insert. For example, during a production process, the textile material can be foamed such that it is integrated into the rigid intermediate layer. This embodiment can provide a further preferred form of attachment of the sensor device to the underbody element.

[0017] In the aforementioned embodiment, it is preferably provided that each end of the sensor wire is connected to a plug unit integrated into the foam insert, wherein the plug unit can be coupled to an evaluation unit of the sensor device by means of a plug via a free opening through at least one of the cover layers and the intermediate layer. In other words, if the textile material with the sensor wire is integrated into the foam insert, a plug unit can additionally be provided in the foam insert, which can, for example, also be foamed in together with the textile material during a manufacturing process. The sensor wire in the textile material can preferably be connected to this plug unit, for example directly or via a metal plate, which in particular provides improved manufacturing tolerance.After a manufacturing process, the connector unit can then be subsequently exposed by a predetermined positioning, for example, by drilling, to gain access to the connector unit. A connector can then be used to couple the connector unit and thus the sensor wire to an evaluation unit of the sensor device. This provides cost-effective, simple, and reproducible contact between the respective ends of the sensor wire to tap voltage signals and thus detect deformation of the underbody element.

[0018] A further aspect of the invention relates to a motor vehicle with an underbody element according to one of the preceding embodiments. The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle. The motor vehicle can preferably be designed as an electrically powered motor vehicle with at least one traction battery.

[0019] In one embodiment of the motor vehicle, it is provided that the motor vehicle has a traction battery and the underbody element comprises a plurality of chambers for arranging battery cells of the traction battery, wherein the textile material with the sensor wire is arranged flatly in the regions of the chambers on or in the underbody element. In other words, the underbody element can have recesses in which battery cells of the traction battery can be arranged. The textile material with the sensor wire can be arranged in these chambers, which preferably represent flat regions in the underbody element. This results in sensor surfaces at the level of the battery cells, wherein each of the chambers can thus have its own sensor wire, whereby in the event of deformation, it can be better determined which chamber has been deformed.This embodiment has the advantage that deformation and thus damage to one of the battery cells can be localized more effectively.

[0020] According to the invention, a method for detecting an intrusion of a traction battery of a motor vehicle is also provided, comprising an underbody element according to one of the preceding embodiments. The method provides that a voltage applied to the sensor wire is measured by a sensor device of the underbody element, which has at least one electrically conductive sensor wire integrated into a flat textile material. Depending on a measured change in the voltage, a deformation of the sensor wire and thus an intrusion of the traction battery is detected. This results in the same advantages and possible variations as with the underbody element and / or as with the motor vehicle with the underbody element.

[0021] The invention also includes the control device for the motor vehicle. The control device can have a data processing device or a processor device configured to carry out an embodiment of the method according to the invention. For this purpose, the processor device can have at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (Field Programmable Gate Array) and / or at least one DSP (Digital Signal Processor). Furthermore, the processor device can have program code configured to carry out the embodiment of the method according to the invention when executed by the processor device. The program code can be stored in a data memory of the processor device.

[0022] The invention also includes further developments of the method according to the invention that have features already described in connection with the further developments of the underbody element according to the invention. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0023] The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations that each comprise a combination of the features of several of the described embodiments, unless the embodiments are described as mutually exclusive.

[0024] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 shows a schematically illustrated motor vehicle with an underbody element according to an exemplary embodiment; Fig. 2 shows a schematically illustrated underbody element with a sensor device according to an exemplary embodiment; Fig. 3 shows a schematically illustrated application location of a textile material with a sensor wire, according to a first exemplary embodiment; Fig. 4 shows a schematically illustrated application location of a textile material with a sensor wire, according to a second exemplary embodiment; Fig. 5 shows a schematically illustrated application location of a textile material with a sensor wire, according to a third exemplary embodiment; Fig. 6 shows a schematically illustrated underbody element with an integrated sensor wire and an integrated plug unit.

[0025] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0026] In the figures, the same reference symbols designate elements with the same function.

[0027] In Fig. 1 A schematic motor vehicle 1 with an underbody element 2 is shown according to an exemplary embodiment. The motor vehicle 1 can be, for example, an electrically powered passenger car. For power supply, the motor vehicle 1 can comprise a traction battery 3 or drive battery, wherein the traction battery 3 can have a plurality of battery cells 4.

[0028] To protect the traction battery 3 and the respective battery cells 4 from impacts from beneath the motor vehicle 1, the underbody element 2, which can be designed as an underride guard, can be arranged below the attachment location of the traction battery 3. Preferably, the underbody element 2 can be designed to protect the traction battery 3 from mechanical influences. Nevertheless, it can happen that a strong impact from beneath the motor vehicle 1, for example, when striking a bollard, leads to an intrusion of the traction battery 3. In order to detect this and warn a driver of the motor vehicle 1 of damage to the traction battery 3, a sensing concept for the traction battery 3 can be provided.

[0029] In Fig. 2 the underbody element 2 of the motor vehicle 1 is shown schematically in a plan view from the direction of the traction battery 3, wherein the traction battery 3 is not shown in this figure. The underbody element 2 can have a plurality of chambers 5, which are designed as flat regions, wherein the battery cells 4 of the traction battery 3 can be arranged in the chambers 5. In order to be able to detect impacts on the traction battery 3 and the respective battery cells 4, a sensor device 6 can be provided, which is arranged flatly in each of the chambers 5, for example. This figure only shows a section of the sensor device 6, wherein the sensor device 6 can preferably be arranged over an entire surface of the chambers 5. The sensor device 6 can be designed to detect a deformation of the underbody element 2 and thus an intrusion on the traction battery 3.The arrangement of the sensor device 6 in the respective chamber has the advantage that a detection of a deformation of the respective chamber 5 is possible and thus a localization of which battery cell 4 has been damaged.

[0030] The sensor device 6 can comprise a flat textile material 7 into which a sensor wire 8 is integrated. The textile material 7, which can also be referred to as a flat textile semi-finished product, can facilitate the attachment of the sensor wire 8 in the underbody element 2, in particular in the chambers 5. The sensor wire 8 can be formed, for example, from a carbon fiber, which can be particularly easily incorporated into the textile material 7 and has suitable fracture and elongation properties. Furthermore, the sensor wire 8 is preferably incorporated into the textile material 7 in a meandering shape, thus providing a good compromise between material savings and covering an area for detection.

[0031] To detect a deformation, it can be provided that a current, in particular with a predetermined voltage, is measured by the sensor device 6 through the sensor wire 8, wherein a deformation of the sensor wire 8 can be determined depending on a change in the voltage. For this purpose, the sensor wire 8 can be designed to change an electrical resistance upon deformation, for example by changing a length and / or a diameter of the sensor wire during the deformation, which leads to a measurable change in resistance. If the sensor wire 8 is bent too sharply and beyond a defined deflection, it can be provided, for example, that a measured change in the voltage lies above a predetermined voltage threshold value, and a driver of the motor vehicle 1 can then receive a warning signal that is generated by the sensor device 6 if the voltage threshold value is exceeded.Thus, a deformation of the underbody element 2 and consequently an intrusion onto the traction battery 3 or one of the battery cells 4 can be easily detected.

[0032] In the Fig. 3 bis 5 Preferred application sites for the sensor wire integrated into the textile material are shown. Fig. 3 A first exemplary embodiment is shown in which the textile material with the sensor wire is arranged on a surface of the underbody element 2, wherein the surface is arranged in the direction of the motor vehicle. That is, on the inside of the underbody element 2 in the direction of the traction battery 3. In this case, the semi-finished textile product (textile material 7) with the sensor wire 8 can be subsequently applied, for example, glued, to the inside of the finished underbody element 2. For this purpose, the textile material 7 can be injected with resin, for example, in a preceding production step in order to produce a thin plate therefrom that can be glued to the surface of the underbody element 2. The underbody element 2 itself can be formed with several layers, in particular with two cover layers 9 and a foam insert 10 as a rigid intermediate layer between the two cover layers 9.

[0033] In Fig. 4 A second exemplary application location for the textile material 7 with the sensor wire 8 in the underbody element 2 is shown. In this exemplary embodiment, the textile material 7 with the sensor wire 8 can, for example, be integrated directly into the underbody element 2, for example by inserting the textile material 7 between the foam insert 10 and one of the cover layers 9 in a wet process. Preferably, the textile material 7 can be inserted between the foam insert 10 and the upper cover layer 9. The cover layer 9 can, for example, be present as a glass layer or a glass fiber core / glass fiber fabric and provide stability to the underbody element 2.

[0034] In Fig. 5 A third exemplary application location for the textile material 7 with the sensor wire 8 is shown. In this exemplary embodiment, the textile material 7 can be foamed directly into a prefabricated foam insert 10 of the underbody element 2. This means that the flat textile material 7 is located in the foam insert 10, which is enclosed by the two cover layers 9.

[0035] In Fig. 6An underbody element 2 with a connector integration for the third exemplary application location is shown, in which the textile material 7 with the sensor wire 8 is integrated into the foam insert 10. In order to contact the sensor wire 8 and tap a signal, in particular to measure the voltage applied to the sensor wire 8, a connector unit 11 can be foamed into the foam insert 10 in addition to the textile material 7 during a manufacturing process. Preferably, the sensor wire 8 can be connected to the connector unit 11, either directly or via a metal plate 12, wherein the metal plate 12 can facilitate a manufacturing process, in particular due to an easier connection of the metal plate 12 to the sensor wire 8.For example, one end of the sensor wire 8 can be fixed to the metal plate 12, in particular by local bonding to the metal plate 12, wherein the metal plate 12 can be electrically coupled to the plug unit 11.

[0036] In order to access the plug unit 11 from the outside, an opening can be created during the manufacturing process through at least one of the cover layers 9 and the foam insert 10 up to the plug unit 11, via which opening the plug unit 11 can be coupled to an evaluation unit 14 of the sensor device 6 by means of a plug 13. In other words, access to the plug unit 11 can be subsequently created by precisely positioning the plug unit 11, for example, by subsequently drilling a hole through the cover layer 9. Another plug unit, not shown here, can connect another end of the sensor wire 8 to another plug that leads to the evaluation unit 14. This makes it possible to provide cost-effective, simple, and reproducible contact between the wire ends in order to be able to tap off signals.

[0037] Overall, the examples show how the invention can provide a sensing concept for a traction battery 3 via resistance sensing in the underbody element 2, in that detection of a deformation of the underbody element 2 allows conclusions to be drawn about an intrusion of battery cells 4.

Claims

1. Underbody element (2) for a traction battery (3) of a motor vehicle (1), comprising at least one sensor device (6), characterized in that the sensor device (6) comprises at least one electrically conductive sensor wire (8), which is integrated into a laminar textile material (7), wherein the sensor device (6) is configured to measure a voltage applied to the sensor wire (8) and to determine a deformation of the sensor wire (8) in dependence on a measured change of the voltage.

2. Underbody element (2) according to claim 1, wherein the sensor wire (8) is integrated in meandering form into the laminar textile material (7).

3. Underbody element (2) according to any one of the preceding claims, wherein the sensor wire (8) is formed of a carbon fiber or a metal-coated plastic filament.

4. Underbody element (2) according to any one of the preceding claims, wherein the sensor wire (8) is configured to change an electric resistance in case of a deformation.

5. Underbody element (2) according to any one of the preceding claims, wherein the sensor device (6) is configured to generate a warning signal in case the measured change of the voltage is above a predetermined voltage threshold value.

6. Underbody element (2) according to any one of the preceding claims, wherein the laminar textile material (7) with the sensor wire (8) is arranged on a surface of the underbody element (2) in the direction of the motor vehicle (1) when the underbody element (2) is installed according to the intended purpose.

7. Underbody element (2) according to any one of claims 1 to 5, wherein the underbody element (2) comprises a foam inlay (10) as bending-resistant intermediate layer between at least two cover layers (9), wherein the laminar textile material (7) with the sensor wire (8) is arranged between the foam inlay (10) and one of the two cover layers (9).

8. Underbody element (2) according to any one of claims 1 to 5, wherein the underbody element (2) comprises a foam inlay (10) as bending-resistant intermediate layer between at least two cover layers (9), wherein the laminar textile material (7) with the sensor wire (8) is integrated into the foam inlay (10).

9. Underbody element (2) according to claim 8, wherein a respective end of the sensor wire (8) is connected to a plug unit (11) that is integrated into the foam inlay (10), wherein the plug unit (11) is capable of being coupled via an exposed opening through at least one of the cover layers (9) and the intermediate layer (10) by a plug (13) into an evaluation unit (14) of the sensor device (6).

10. Motor vehicle (1) comprising an underbody element (2) according to any one of the preceding claims.

11. Motor vehicle (1) according to claim 10, wherein the motor vehicle (1) comprises a traction battery (3) and the underbody element (2) comprises several chambers (5) for the arrangement of battery cells (4) of the traction battery (3), wherein the textile material (7) with the sensor wire (8) is arranged in a laminar way in the regions of the chambers (5) on or in the underbody element (2).

12. Method for determination of an intrusion into a traction battery (3) of a motor vehicle (1), comprising an underbody element (2) according to any one of claims 1 to 9, wherein by a sensor device (6) of the underbody element (2) comprising the at least one electrically conductive sensor wire (8), which is integrated into a laminar textile material (7), a voltage applied to the sensor wire (8) is measured and in dependence on a measured change of the voltage a deformation of the sensor wire (8) and thus an intrusion into the traction battery (3) is determined.