Traction battery arrangement for a motor vehicle for detecting an impact on a traction battery, as well as a motor vehicle with a traction battery arrangement.

Description

[0001] The invention relates to a traction battery arrangement for a motor vehicle for detecting an impact on a traction battery and to a motor vehicle with a traction battery arrangement.

[0002] Nowadays, many motor vehicles are designed to be partially or fully electric, for example as hybrid vehicles or purely electric vehicles. The traction battery required for this, which typically comprises several battery cells, is usually located in the vehicle's underbody. This has the disadvantage that impacts from below directly affect the traction battery, which can lead to damage. To limit or prevent damage from below, it is known to use an underbody element for the traction battery, which can, for example, be designed as an underride guard to protect the traction battery from direct impact. This underbody element can be a cover on the underbody of the traction battery and / or the vehicle, shielding the traction battery from environmental and / or mechanical influences.

[0003] However, even an underbody element cannot completely protect the traction battery from all impacts. In the case of strong impacts from below, such as when the vehicle bottoms out after driving over a bollard, the underbody element can be forced into the traction battery, causing damage. This means that an impact can result in intrusion of the traction battery. To detect this type of damage and minimize consequential damage to the vehicle and / or risks to the driver, it is necessary to detect impacts on the traction battery. This allows conclusions to be drawn about whether the battery cells have been damaged. Therefore, a sensing system is required to detect impacts or deformation of the traction battery.

[0004] From DE 10 2018 126 572 A1, a high-voltage battery for an electrically powered motor vehicle is known, comprising at least one battery module with a plurality of battery cells, a battery housing with housing walls that enclose a mounting frame for the at least one battery module, and at least one spring element designed to elastically mount the battery module relative to the battery housing and to absorb a shock-induced force introduced into the high-voltage battery. The at least one spring element is designed as an elastic fluid cushion that is arranged between at least one housing wall and one side of the at least one battery module facing the at least one housing wall.

[0005] From DE 10 2019 207 435 A1, an underride guard for a vehicle is known, wherein the underride guard is arranged above the drivable ground on the underbody of the vehicle and consists of at least three layers, namely an outer layer adjacent to the drivable ground, an inner layer adjacent to the interior of the vehicle, and an intermediate layer that creates a defined distance between the outer and inner layers. A force-induced approach of the outer and inner layers and / or of the elements of an electrical circuit arranged directly or indirectly thereto causes a detectable change in an electrical property of the electrical circuit.

[0006] The invention is based on the objective of detecting an impact on a traction battery originating from below the motor vehicle.

[0007] This problem is solved by the independent patent claims. Advantageous embodiments of the invention are disclosed in the dependent patent claims, the following description, and the figures.

[0008] The invention provides a traction battery assembly for a motor vehicle for detecting an impact on a traction battery. The traction battery assembly comprises the traction battery and an underbody element arranged on the underside of the traction battery, wherein the underbody element has at least one recessed area, which is provided as a recess in the underbody element in which an air-filled chamber is formed between the underbody element and the underside of the traction battery, wherein the chamber is coupled to an evaluation unit configured to determine a pressure signal of the air pressure in the chamber and, depending on the pressure signal, to detect the impact on the traction battery.

[0009] In other words, an underbody element is arranged below the traction battery, and cooling for the traction battery can be provided between the traction battery and the underbody element. The underbody element has a recessed area, preferably above which the battery cells of the traction battery can be arranged. The recessed area can, for example, extend lengthwise across the underbody element and additionally provide an air gap between the underbody element and the traction battery, thus creating the air-filled chamber. This air-filled chamber can be connected to an evaluation unit, which may include at least one pressure sensor and a computing device, such as a computer or a control unit.If a physical force acts on the underbody element from below, the air-filled chamber can deform or compress, thus generating increased air pressure, which can be measured as a pressure signal by the evaluation unit. In other words, if the underbody element, and therefore the air-filled chamber, deforms, the volume decreases, which can be determined as a measurable pressure increase.

[0010] The invention offers the advantage that an impact from below onto the vehicle, in particular the traction battery assembly, can be determined with relatively little effort and at low cost. Preferably, the traction battery assembly on the underbody element can also have several air-filled chambers, each connected to the evaluation unit or a separate evaluation unit. This allows, for example, the localization of where the impact on the traction battery assembly occurred.

[0011] The invention also includes embodiments that offer additional advantages.

[0012] In one embodiment, the chamber is sealed laterally around its perimeter by a sealing material, in particular a polyurethane seal. This means that, for example, a sealing foam, especially polyurethane, can be used to seal the chamber to the outside, thus providing a hollow body in which pressure can build up upon impact by reducing its volume. The sealing material, especially polyurethane, offers the advantage that the underbody element can be pressed against the traction battery during manufacturing, creating a sealed chamber in which, upon pressure increase, the air pressure is not released to the surrounding environment but is instead directed to the evaluation unit. This increases the pressure signal upon impact, allowing it to be more accurately determined by the evaluation unit.

[0013] In a further preferred embodiment, the chamber in the recessed area is designed as an air-filled foil body. This means that an air-filled foil body, coupled to the evaluation unit, can be arranged in the recessed area of ​​the underbody element. For example, a foil cushion, which can be formed in one piece and manufactured, for example, by blow molding, can be used as the foil body. The foil body can preferably be unrolled or placed in a defined installation space, particularly in the recessed area, and can be laterally secured, for example, by existing tabs in the recessed area.This design offers the advantage that moisture, which can accumulate in the recessed area due to cooling of the traction battery, can be drained away, since the recessed area itself does not need to be sealed airtight and thus drainage channels for condensation can be provided, as the sealed foil body serves to sensing the pressure signal. This reduces the risk of corrosion for surrounding components, especially the traction battery.

[0014] Preferably, at least one spacer is arranged within the film body, designed to maintain an air-filled volume within the film body. Furthermore, the spacer can increase the stability of the film body. The film body can, for example, be designed as a thin film that can collapse under low air pressure. By using a spacer, a volume can be maintained within the film body that, when the underbody element deforms and thus the film body is compressed, can generate the pressure signal. The spacer can also facilitate the transmission and propagation of the pressure signal. The at least one spacer can preferably be designed with nubs or ridges and extend over the entire film body.Preferably, the spacer is designed to generate support at a sufficient number of points in the foil body so that a sufficiently large volume of air can be provided.

[0015] It is particularly preferred that the spacer be elastically deformable. For example, the spacer can be made of foam, especially polyurethane foam or particle foam. Other preferred alternatives are that the spacer incorporates spring elements and / or spacer textiles that counteract the collapse of the film body. The elastic spacer offers the advantage that the film body is "self-inflating" and can conform to the surrounding contour. Thus, like a self-inflating sleeping mat, the film body can create a volume that can build up pressure when deformed. When the underbody element is mounted with the traction battery, the film body can also be compressed to adapt to the installation space in the recessed area.

[0016] Preferably, the film body has a plurality of air chambers. This means that the film body can be, for example, made of two or more parts. This can be achieved, for example, by welding or bonding together at least two deep-drawn films or mold halves of the film body. This offers the advantage that the volume of the film body can be maintained more effectively, since the volume can be divided among several air chambers. Thus, the film body does not collapse as quickly, because a higher pressure can be maintained in the individual air chambers during the manufacturing process.Preferably, each of the air chambers can be coupled to the evaluation unit, in particular a pressure sensor of the evaluation unit, so that a more accurate localization of the impact can be carried out by determining which air chamber provides the highest pressure signal.

[0017] In a further embodiment, the chamber has at least one inlet valve and a hose connection, wherein the hose connection is configured to connect the chamber to the evaluation unit via a pressure hose, and wherein the inlet valve is configured to introduce air at a predetermined pressure into the chamber, the inlet valve being coupled to the chamber via the pressure hose and / or separately from the pressure hose. In other words, the air-filled chamber, in particular the foil body, can have at least one inlet valve for air and a hose connection to which a pressure hose can be attached, which can transmit a pressure signal from the chamber to the evaluation unit. Thus, for example, pressure can be built up in the chamber via the inlet valve during the manufacture of the traction battery assembly.Thus, a predetermined pressure is maintained in the chamber, which can be measured by the evaluation unit. A change in this pressure can indicate an impact. Preferably, the chamber can be continuously pressurized via the inlet valve to a predetermined pressure, which can be kept constant. In the event of a rapid pressure change, the evaluation unit can then detect that an impact has occurred on the traction battery assembly. The advantage of the hose connection and the connection via the pressure hose to the evaluation unit is that the evaluation unit does not need to be placed directly on the air-filled chamber. This simplifies the manufacture of the traction battery assembly, as less installation space is required on the chamber. The inlet valve and the hose connection can, for example, be located at separate positions within the chamber.Alternatively or additionally, the inlet valve can also be connected to the chamber via the hose connection, particularly via a pressure sensor of the evaluation unit. This allows for additional space savings.

[0018] Another embodiment provides that the evaluation unit is configured to analyze the pressure signal for a pressure maximum, a duration of pressure above a predetermined threshold, an integral of the pressure, and / or a slope of the pressure in order to detect the impact. In other words, the pressure signal can be analyzed and evaluated by the evaluation unit, in particular by a computing unit of the evaluation unit, using an algorithm.In particular, to determine whether an impact has occurred, a pressure maximum of the pressure signal can be compared with a predefined pressure maximum threshold, the duration of the pressure can be checked to see if it exceeds a predefined threshold, an integral over a pressure curve can be determined, and / or the slope of the pressure gradient (i.e., the rate of pressure increase in the chamber) can be analyzed to determine whether an impact on the traction battery assembly, and thus on the traction battery itself, has occurred. This allows for improved impact detection and, for example, reduces false-positive warnings that can occur during normal vehicle operation.

[0019] In a further embodiment, the evaluation unit is configured to receive vehicle sensor data and / or environmental sensor data from the motor vehicle and to validate the specific pressure signal based on this data, and / or to adjust the sensitivity for detecting the impact. In other words, the evaluation unit can receive vehicle sensor data and / or environmental sensor data, for example, via a vehicle bus. This data can then be compared with the pressure signal to determine whether or not an impact has occurred. Vehicle sensor data can include, for example, the acceleration of the motor vehicle in any spatial direction and derived criteria such as velocity.Furthermore, vehicle sensor data can provide information on the suspension travel of the vehicle's shock absorbers, which can be used to detect, for example, driving over bumps, particularly curbs. This allows for determining whether the pressure signal can be correlated with an actual measured event outside the vehicle, thereby improving impact detection and reducing false positives. Additionally, environmental sensor data, such as data from a vehicle camera and / or radar, can be used to correlate external conditions with the pressure signal. For example, a recorded road surface irregularity, when correlated with the pressure signal, can indicate damage to and impact of the traction battery assembly.Alternatively or additionally, the sensitivity for impact detection can be adjusted using vehicle sensor data and / or environmental sensor data. This means that, for example, depending on the vehicle's speed, the pressure change threshold at which an impact should be detected can be set, as certain damage events may only occur or be critical within a specific speed range. The sensitivity can also be adjusted based on detected objects on the road surface, determining the pressure change threshold at which an impact should be detected. For instance, if road damage or a speed bump is detected, the evaluation unit can be informed of this information to increase the impact detection sensitivity. Overall, this can improve the detection of impacts on the traction battery assembly.

[0020] According to the invention, a motor vehicle with a traction battery arrangement according to one of the preceding embodiments is also provided. This offers the same advantages and possibilities for variation as the traction battery arrangement. 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.

[0021] Another aspect of the invention relates to a method for detecting an impact on a traction battery assembly according to one of the preceding embodiments, wherein in the method a pressure signal in the chamber is determined, it is determined whether a change in the pressure signal exceeds a predetermined pressure threshold, and the impact on the traction battery is detected if it is found that the change in the pressure signal exceeds the predetermined threshold. This offers the same advantages and possibilities for variation as with the traction battery assembly.

[0022] The invention also includes a control device for the motor vehicle. The control device can comprise an evaluation unit and a data processing device or a processor unit configured to perform a method for detecting an impact on a traction battery in a traction battery arrangement according to one of the preceding embodiments. For this purpose, the processor unit can comprise 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 unit can comprise program code configured to perform the embodiment of the method according to the invention when executed by the processor unit. The program code can be stored in a data memory of the processor unit.

[0023] The invention also includes further developments of the method which have features already described in connection with the further developments of the traction battery arrangement according to the invention. For this reason, the corresponding further developments of the method are not described again here.

[0024] The invention also includes combinations of the features of the described embodiments. The invention therefore also includes realizations that each exhibit a combination of the features of several of the described embodiments, provided that the embodiments have not been described as mutually exclusive.

[0025] The following are exemplary embodiments of the invention described. This is illustrated by: Fig. 1 a schematic representation of a motor vehicle with a traction battery arrangement according to an exemplary embodiment; Fig. 2 a schematic top view of an underbody element according to an exemplary embodiment; Fig. 3 a schematic cross-sectional view of an underbody element according to an exemplary embodiment.

[0026] The exemplary embodiments described below are preferred embodiments of the invention. In these exemplary embodiments, the described components each represent individual features of the invention, which can be considered independently of one another and each further develops the invention independently. Therefore, the disclosure is intended to include combinations of features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0027] In the figures, identical reference symbols denote functionally equivalent elements.

[0028] In Fig. 1 Figure 1 shows a schematic representation of a motor vehicle 1 with a traction battery arrangement 2 according to an exemplary embodiment. The motor vehicle 1 can, for example, be an electrically powered passenger car. For energy supply, the traction battery arrangement 2 of the motor vehicle 1 can comprise a traction battery 4, or drive battery, wherein the traction battery 4 can, for example, have several battery cells, which are not shown in this figure.

[0029] To protect the traction battery 4 from impacts from below the vehicle 1, the traction battery assembly 2 can have an underbody element 3, which is arranged on the underside of the traction battery 4 and which can be designed as an underride guard. This means that the underbody element 3 is positioned below the mounting location of the traction battery 4. Additionally, the traction battery assembly 2 can have a cooling system for the traction battery 4, which is preferably arranged between the traction battery 4 and the underbody element 3, although this is not shown in this figure. The underbody element 3 can preferably be designed to protect the traction battery 4 from mechanical impacts. Nevertheless, it is possible that a strong impact from below the vehicle 1, for example, when driving over a bollard, could cause the traction battery 4 to be struck.In order to determine this and to warn a driver of motor vehicle 1 of damage to the traction battery 4, a sensing concept for the traction battery 4 can therefore be provided.

[0030] To provide the sensing concept, one or more recessed areas 5 can be provided in the underbody element 3, in which an air-filled chamber is formed. The air-filled chamber can be provided either by a cavity formed between the recessed area 5 and the traction battery 4, or by arranging a device in the recessed area, in particular by arranging a foil body. If the underbody element 3 is deformed and thus the air-filled chamber is compressed, a pressure change can occur in the chamber, which can be detected, thereby enabling the detection of an impact on the traction battery.

[0031] In Fig. 2 Figure 1 shows a schematic top view of the underbody element 3 of the motor vehicle 1 from the direction of the traction battery 4. The underbody element 3 can, for example, have several recessed areas 5, which can serve as an air-filled chamber between the underbody element 3 and the traction battery 4. The respective recessed areas 5 can be designed as planar areas, with the battery cells of the traction battery 4 being arranged above these areas 5. An air gap or a hollow body can form between the battery cells of the traction battery 4 and the bottom of the respective recessed area 5, which can be deformed upon impact.To reduce pressure loss from the chambers to the outside, it can additionally be provided that a sealing material 8, in particular a polyurethane seal, is applied laterally around the recessed areas 5, which seal the air-filled chambers laterally around the perimeter, wherein the chambers are sealed upwards and downwards by the underbody element 3 and the traction battery 4.

[0032] If a pressure difference is detected, it can be registered as an impact. To detect this pressure signal, the respective chambers can have hose connections 6 in the recessed areas 5, which transmit the pressure signal, in particular to an evaluation unit 7. The evaluation unit 7 can have at least one pressure sensor and a processing unit, for example a computer, which are configured to analyze the pressure signal and thus determine an impact on the traction battery assembly 2. Preferably, the evaluation unit 7 can also be configured to receive vehicle sensor data and / or environmental sensor data from the motor vehicle 1 and to validate the pressure signal based on this sensor data.This means that, for example, the vehicle sensor data can include the degree to which a shock absorber of the vehicle 1 was deflected and determine the magnitude of the pressure signal, in particular a pressure maximum and / or the duration of the pressure. If these values ​​exceed a predefined threshold and a deflection of the suspension travel exceeding a predetermined value has been detected simultaneously, it can be determined that an impact on the traction battery 4 has occurred. Alternatively or additionally, environmental sensor data, i.e., camera or radar data from the vehicle 1, can be used to determine whether there is an object in the vehicle's vicinity capable of impacting the traction battery assembly 2. Together with this information, the pressure signal can then be validated to determine whether an impact has occurred or not.

[0033] In Fig. 3Figure 1 shows a schematic cross-sectional view of an underbody element 3 according to an exemplary embodiment. In this embodiment, the air-filled chamber in the recessed area 5 can be designed as an air-filled film body 9. The film body 9 can, for example, be a film cushion, which is designed in one or more parts and which is unrolled or placed in the respective recessed area 5 during a manufacturing process. For this purpose, the film body 9 can be attached to existing tabs 10 in the recessed area 5. Subsequently, the film body 9 can be filled with air via one or more inlet valves 11. For example, one of the inlet valves 11 can be connected to the film body 9 via the hose connection 6 by coupling it to the film body 9 via the evaluation unit 7 and a pressure hose 12.Alternatively, the inlet valve 11 can also have its own independent access to the foil body 9.

[0034] To prevent the foil body 9 from collapsing over time, one or more spacers 13 can be provided within it to maintain its volume. The spacer 13 can, for example, have a dimpled shape and be made primarily of polyurethane. In particular, a material can be used that ensures elastic deformability of the spacers 13. Thus, the spacer 13 can be spring-loaded, pressing the foil body 9 against itself in an inflatable manner and thereby maintaining a constant volume within the foil body 9 during normal operation. Furthermore, during a manufacturing process, the foil body 9 can be pressed against the traction battery 4, allowing it to conform to the space between the recessed area 5 and the traction battery 4.

[0035] If an impact occurs from below, a pressure signal can be generated in the foil body 9, as described above. This signal is transmitted via the hose connection 6 and the pressure hose 12 to the evaluation unit 7, which is designed to detect the impact on the traction battery 4 based on the pressure signal. The design with the foil body 9 has the advantage that the recessed area 5 does not need to be sealed airtight. Therefore, water, which may accumulate, for example, due to the cooling of the traction battery 4, can drain away from the recessed areas 5 through suitable drainage openings, thus reducing the risk of corrosion to the surrounding components.

[0036] Overall, the examples show how the invention can provide a sensing of deformations by means of a closed hollow body.

Claims

1. A traction battery assembly (2) for a motor vehicle (1) for detecting an impact with a traction battery (4), comprising the traction battery (4) and an underbody element (3), which is arranged on an underside of the traction battery (4), wherein the underbody element (3) comprises at least one recessed region (5), which is provided as a cut-out in the underbody element (3), in which an air-filled chamber is formed between the underbody element (3) and the underside of the traction battery (4), wherein the chamber is coupled to an evaluation unit (7), which is designed to determine a pressure signal for an air pressure in the chamber and to detect the impact with the traction battery (4) on the basis of the pressure signal.

2. The traction battery assembly (2) according to claim 1, wherein the chamber is laterally peripherally sealed against the outside by a sealing material (8), in particular by a polyurethane seal.

3. The traction battery assembly (2) according to any of the preceding claims, wherein the chamber is designed as an air-filled film body (9) in the recessed region (5).

4. The traction battery assembly (2) according to claim 3, wherein at least one spacer (13), which is designed to maintain an air-filled volume in the film body (9), is arranged in the film body (9).

5. The traction battery assembly (2) according to claim 4, wherein the at least one spacer (13) is designed to be elastically deformable.

6. The traction battery assembly (2) according to any of claims 3 to 5, wherein the film body (9) comprises a plurality of air chambers.

7. The traction battery assembly (2) according to any of the preceding claims, wherein the chamber comprises at least an inlet valve (11) and a hose connection (6), wherein the hose connection (6) is designed to connect the chamber to the evaluation unit (7) via a pressure hose (12), and wherein the inlet valve (11) is designed to introduce air having a predetermined pressure into the chamber, wherein the inlet valve (11) is coupled to the chamber via the pressure hose (12) and / or separately from the pressure hose (12).

8. The traction battery assembly (2) according to any of the preceding claims, wherein the evaluation unit (7) is designed to analyze the pressure signal up to a pressure maximum, a duration of the pressure above a predetermined threshold value, an integral of the pressure, and / or an edge steepness in order to detect the impact.

9. The traction battery assembly (2) according to any of the preceding claims, wherein the evaluation unit (7) is designed to receive vehicle sensor data and / or surround sensor data from the motor vehicle (1) and to determine the plausibility of the determined pressure signal on the basis of the vehicle sensor data and / or the surround sensor data, and / or to set a sensitivity for detecting the impact.

10. A motor vehicle (1) comprising a traction battery assembly (2) according to any of the preceding claims.

11. A method for detecting an impact with a traction battery assembly (2) according to any of claims 1 to 9, wherein the method comprises the following steps: - determining a pressure signal for an air pressure in the chamber; - determining whether a change in the pressure signal is above a predetermined pressure threshold value; - detecting the impact with a traction battery (4) of the traction battery assembly (2) if it is established that the change in the pressure signal is above the predetermined threshold value.

12. A control device which is designed to carry out the method according to claim 11.