Measuring setup and method for detecting a specific type of battery damage

Abstract

The invention relates to a measuring arrangement (10) for detecting a specific damage (B) to a battery caused by an external force (K) applied by an object (31) to a protective plate (30) arranged below the battery (38), wherein the measuring arrangement (10) comprises a measuring device (12) and a control device (14) coupled thereto, which is designed to determine the specific damage (B) as a function of a measurement signal (A1, A2) detected by means of the measuring device (12).The measuring device (12) comprises an electrical resonant circuit (16) arranged on the top (30a) of the protective plate (30), with an inductive resonant circuit part (16a) and a capacitive resonant circuit part (16b), and an excitation unit (22) coupled to the resonant circuit (16) for exciting the resonant circuit (16) and for detecting a response signal (A1, A2), wherein the control device (14) is designed to determine a resonance frequency (FR) of the resonant circuit (16) depending on the detected response signal (A1, A2) and to detect the specific damage (B) depending on the determined resonance frequency (FR).

Description

[0001] The invention relates to a measuring arrangement for detecting specific damage to a battery caused by an external force applied by an object to a protective plate arranged under the battery in a defined direction and at least in a defined area at a distance from the battery. The measuring arrangement comprises the protective plate, which has a top surface facing the battery, a measuring device, and a control device coupled to it, which is designed to determine the specific damage as a function of a measurement signal detected by the measuring device. The invention further relates to a method for detecting specific damage to a battery.

[0002] In motor vehicles, especially electric vehicles, the battery, such as a high-voltage battery, is often located in the underbody. Driving over bollards or other obstacles can therefore damage the battery from below, either through impact or intrusion of such external objects. To protect the battery, an underbody protection plate is often installed beneath it. This plate may have a gap between it and the battery, at least in some areas, thus providing a buffer zone against external forces from below. Nevertheless, very strong impacts can still damage the battery. Ideally, this should be detectable as easily and reliably as possible.

[0003] DE 10 2017 206 663 A1 describes a battery pack with a battery housing that has at least one electrically insulating protective plate and at least one deformation sensor comprising an electrically conductive coating applied to the protective plate. An evaluation circuit detects a change in resistance of the at least one deformation sensor. Multiple deformation sensors can be provided, arranged in separate segments of the protective plate.

[0004] German patent DE 10 2021 122 968 A1 describes a protective plate for a battery comprising a first and second layer with a compressible layer between them. The protective plate also integrates a distance measuring device for determining the distance between the first and second layers. The sensors used for implementing the distance measuring device can operate according to any principle and can be, for example, capacitive, optical, inductive, or acoustic sensors. Distance measurement can also be achieved by measuring the electrical resistance of the compressible layer.

[0005] WO 2023 / 006914 A1 describes a fiber composite component that incorporates a sensor element, which is an electrically conductive structure insulated from the fiber material. The sensor element can detect whether the integrity of the fiber composite component is compromised. The sensor element can be an electrical conductor that forms part of a closed circuit consisting of an electrical conductor and an evaluation unit.

[0006] DE 10 2022 117 853 A1 describes a system for detecting damage to a battery system, wherein the system comprises a protective plate arranged on the underside of the battery system and spaced apart from the battery system in sections. The system also includes a sensor device with distance sensors for detecting the distance between the battery system and the protective plate. The distance sensors can be designed as inductive distance sensors comprising a planar coil, or they can be designed as capacitive sensors, optical sensors, infrared sensors, thermal imaging cameras, radar sensors, LiDAR sensors, sonar sensors, ultrasonic sensors, or electromagnetic sensors.

[0007] To monitor a battery for the occurrence of a specific type of damage, particularly caused by an object striking a protective plate from below, complex setups and monitoring structures, and especially numerous and distributed sensors, are usually required.

[0008] The object of the present invention is to provide a measuring arrangement and a method for detecting a specific type of damage to a battery, which makes it possible to detect such damage caused by an external object striking a protective plate from below in the simplest and most reliable way possible.

[0009] This problem is solved by a measuring arrangement and a method with the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0010] A measuring arrangement according to the invention for detecting a specific type of damage to a battery caused by an external force applied by an object to a protective plate arranged below the battery in a defined direction and having a distance to the battery in at least a certain area, comprises the protective plate having a top surface facing the battery, comprising a measuring device and having a control device coupled to it, which is designed to determine the specific damage depending on a measurement signal detected by means of the measuring device.The measuring device comprises an electrical resonant circuit arranged on the top of the protective plate, with an inductive resonant circuit section and a capacitive resonant circuit section, as well as an excitation unit coupled to the resonant circuit for exciting the resonant circuit and for detecting a response signal of the resonant circuit to the excitation as the measuring signal, wherein the control device is designed to determine a resonant frequency of the resonant circuit depending on the detected response signal and to detect the specific damage depending on the determined resonant frequency.

[0011] The invention is based on the understanding that contact between the resonant circuit and the battery above it changes the resonant frequency of the circuit, allowing such contact to be reliably detected as a specific type of battery damage. In particular, the invention is based on the understanding that this allows for the reliable detection of non-critical deformations of the protective plate, where, for example, the distance to the battery above is reduced but no contact occurs, and critical deformations, where such contact or even intrusion into the battery takes place, based on the resonant frequency of the circuit. Furthermore, the invention is also based on the understanding that an electrical resonant circuit allows for a particularly flexible and, above all, planar layout.In particular, the capacitive resonant circuit component can, if desired, be deployed over a large area and / or at least extended significantly in one direction, enabling deformation detection and monitoring over any desired area. This allows for monitoring across large sections of a battery using, for example, just one or a few such measuring devices. This, in turn, reduces the number of sensors required for battery monitoring, and enables a particularly simple and cost-effective way to monitor the battery for specific types of damage.

[0012] The battery can also optionally be part of the measuring setup. The battery can, for example, be a high-voltage battery for a motor vehicle, particularly an electric vehicle. With regard to its intended installation position in the motor vehicle, it should preferably be located in an underbody area. With regard to such an intended installation position, the protective plate can be located below the battery in the vehicle's vertical direction. The protective plate can be part of the vehicle's underride protection. It can extend across the entire battery in the plane perpendicular to the vehicle's vertical direction. The protective plate can also be locally attached to the underside of the battery, the battery housing, or another body component of the motor vehicle. Apart from these attachment points, the protective plate maintains a distance from the battery.

[0013] If the control unit detects specific damage to the battery, it can output a signal depending on this detection, for example, a warning signal and / or a control signal to initiate a protective measure or countermeasure, or similar. The control unit can therefore output a signal depending on the detection of specific damage.

[0014] Accordingly, a further advantageous embodiment of the invention is achieved if the control device detects contact between the protective plate and the battery in at least one specific area and / or an intrusion into the battery as the specific type of damage. These two cases, namely contact with the battery and an intrusion, pose particularly high risks. For example, an intrusion into the battery can cause thermal runaway of battery cells, potentially leading to a battery fire. Therefore, it is advantageous to be able to detect these types of damage as reliably as possible and, above all, to distinguish them from less critical cases.For example, if there is only contact with the protective plate or deformation of the protective plate, and no contact with the battery, it can be assumed that the battery has not sustained any damage as a result of this external force. This case is therefore significantly less critical. Accordingly, more tailored protective measures can be initiated when these different critical cases are detected. If only an impact on the protective plate is detected, a less drastic measure can be taken than if specific damage is detected. For example, a specific measure can be initiated depending on the detection result, and in particular, the specific measure can be selected from several possible measures depending on the detection result.

[0015] According to a further advantageous embodiment of the invention, the measuring arrangement comprises an electrically conductive layer, which is arranged on or provided by the underside of the battery facing the protective plate, and which is contacted by at least a part of the electrical resonant circuit, particularly when a specific type of damage occurs. The contact of the resonant circuit with such an electrically conductive layer significantly alters the resonant frequency, especially due to the capacitive resonant circuit component, which can thereby be electrically short-circuited. This can then be detected by the control device in a particularly simple and reliable manner.

[0016] The battery can comprise a battery casing in which battery cells are arranged. The battery casing can, in turn, have a base, which may be made of a metallic material. In this case, an additional electrically conductive layer is not required. If part of the resonant circuit comes into contact with this metallic base, the resonant circuit is closed, in particular the capacitive part of the circuit is bridged, resulting in a corresponding frequency shift of the resonant frequency of the circuit. This can be reliably detected. If the base is made of a non-conductive material, for example, it can be additionally coated with an electrically conductive layer on its underside.

[0017] According to a further advantageous embodiment of the invention, the control device is designed to detect specific damage under the condition that the specific resonant frequency is predetermined relative to a specific reference resonant frequency assigned to the resonant circuit. This reference resonant frequency can correspond to the resonant frequency of the resonant circuit when it is not in contact with the battery located above it. This reference resonant frequency can therefore be defined for a specific normal operating condition. This reference resonant frequency is typically determined by known parameters of the resonant circuit, such as its inductance and capacitance. The reference resonant frequency can be stored as a predefined value in a memory of the control device, but this is not necessarily required.The reference resonant frequency can also be a resonant frequency determined from one or more previously acquired response signals, or an average of such previously acquired resonant frequencies, or something similar. The control device can also be designed to monitor repeatedly acquired resonant frequencies for the occurrence of a predetermined, significant change, in order to detect the specific damage in such a case.

[0018] Although other external parameters, such as temperature, may have a slight influence on such a resonant frequency, contact of a part of the resonant circuit with the battery above it or with the electrically conductive layer leads to such a significant shift in the resonant frequency that such contact can be reliably detected as the specific type of damage and, above all, can be clearly distinguished from and in the minor shifts caused by external influences such as temperature.

[0019] For example, a suitable threshold value can be defined for such a predetermined change in the resonant frequency at which the specific damage is considered detected. If the change in the specific resonant frequency relative to the reference resonant frequency is greater, particularly in magnitude, than such a predetermined threshold value, then the specific damage can be considered detected. Specifically, the resonant frequency decreases when the specific damage occurs, i.e., when the resonant circuit comes into contact with the battery above it. The control device can therefore be designed to detect the specific damage under the condition that the specific resonant frequency is reduced significantly relative to the predetermined reference resonant frequency.

[0020] According to a further advantageous embodiment of the invention, the excitation unit is designed to repeatedly and / or continuously excite the resonant circuit and to repeatedly or continuously detect the corresponding response signal. The control unit is designed to repeatedly or continuously determine the resonant frequency of the resonant circuit based on the repeatedly or continuously detected response signal and to monitor the battery for the occurrence of the specific damage based on the repeatedly or continuously determined resonant frequency. Thus, the control unit can continuously or repeatedly check whether the resonant frequency of the resonant circuit is changing, particularly by a predetermined amount, thereby advantageously enabling the detection of the specific damage.This allows for continuous monitoring of the battery for the occurrence of specific damage.

[0021] According to a further advantageous embodiment of the invention, the protective plate is elastically deformable by the external force applied by the object, wherein the control device is designed to detect, depending on the repeatedly or continuously determined resonance frequency, a only temporary predetermined change in the determined resonance frequency relative to the reference resonance frequency, in particular with a duration in the range of five milliseconds to a maximum of 200 milliseconds, and, provided that the only temporarily predetermined change is detected, to detect the specific damage. This is particularly advantageous if the protective plate is, for example, made of or comprises a plastic material. In this case, in the event of an external force being applied, the protective plate is primarily deformed elastically.This means that the resonating circuit is deformed in the direction of the battery and then springs back approximately to its original position when the external force is removed. As a result, in the event of specific battery damage, contact between the resonant circuit and the battery above it is only temporary. By repeatedly or continuously monitoring the resonant frequency of the circuit, even such temporary changes in frequency can be reliably detected. It is further preferred that the resonant frequency be repeatedly monitored at maximum intervals, for example, between five and 200 milliseconds. This allows even very short-term changes in the resonant frequency of the circuit, and thus the specific damage, to be reliably detected.

[0022] According to a further advantageous embodiment of the invention, the protective plate is plastically deformable by the force applied by the object, wherein the control device is designed to detect a permanent, predetermined change in the specific resonant frequency relative to the reference resonant frequency, depending on the specific resonant frequency, and to detect the specific damage provided that the permanent, predetermined change is detected. If the protective plate is, for example, made of a metallic material, in which case the electrical resonant circuit can be arranged on the protective plate in an electrically insulated manner, then in the event of an external force being applied, a plastic deformation of such a protective plate occurs. In particular, the contact between the resonant circuit and the battery located above it can be permanent.In this case, too, it is advantageous if the control unit repeatedly detects the resonant frequency of the oscillating circuit, as described above. This allows for the reliable detection of any persistent shift in the resonant frequency and, consequently, the specific battery damage causing it. Nevertheless, it is not necessary to determine the resonant frequency particularly frequently in this case. Specifically, it can be performed repeatedly at intervals significantly longer than the time span mentioned above. For example, repeated determination and verification of the resonant frequency at intervals of seconds or even minutes would suffice. This also simplifies the evaluation of the response signal.

[0023] Furthermore, it is also possible to consider the duration of the resonant frequency shift during the detection of a specific type of damage, for example, as an additional parameter to verify the detection of that particular damage and / or to differentiate it from other cases. In the case of an elastically deformable protective plate, for instance, external force will only cause a very brief, temporary deformation of the protective plate, and contact with the battery above it will only result in a very short-term contact on the order of milliseconds. If a frequency shift of the resonant circuit is caused by other influences, such as fluid in the vicinity of the resonant circuit, this will result in a frequency shift of the resonant frequency that lasts significantly longer than milliseconds, thus allowing these cases to be distinguished.

[0024] Similarly, such an evaluation can also be used if the protective plate undergoes plastic deformation under external force. In the case of specific damage, this results in a permanent shift in the resonant frequency. If, on the other hand, only a temporary shift in the resonant frequency occurs, it can be assumed that this most likely has a different cause.

[0025] Additionally or alternatively, other parameters of the response signal can be evaluated to verify the detection of the specific damage, for example, the signal quality. If the resonant circuit comes into contact with liquid, this also affects the signal quality, particularly depending on the type of liquid. For example, the signal quality decreases if the resonant circuit comes into contact with water. However, contact between the resonant circuit and the battery above it, whether permanent or temporary, leaves the signal quality essentially unaffected.

[0026] Accordingly, a further advantageous embodiment of the invention is achieved if the control device is designed to detect the specific damage, provided that the determined quality of the response signal meets a predetermined criterion. This predetermined criterion could, for example, consist of the determined quality being essentially unchanged compared to a predefined reference quality. This allows for the differentiation of significantly more distinct fault cases and enables even more reliable detection of the specific damage.

[0027] According to a further advantageous embodiment of the invention, the excitation unit for exciting the resonant circuit and for detecting the response signal comprises an excitation coil that is inductively coupled to the inductive resonant circuit section. The inductive resonant circuit section can also be provided in the form of a coil. Thus, the resonant circuit can be easily excited inductively. Furthermore, the excitation unit can be designed to excite the resonant circuit with one or more different frequencies, including the reference resonant frequency and / or other frequencies, particularly in a predefined range around or below the reference resonant frequency. This allows for the reliable and simple detection of both the "normal case," in which the resonant circuit has the reference resonant frequency as its resonant frequency, and fault cases with a resonant frequency shifted relative to it.The maximum amplitude deflection in the response signal will then automatically occur at the current resonant frequency of the resonant circuit.

[0028] Alternatively, the resonant circuit can be conductively driven by applying an alternating voltage of a specific frequency or frequencies to one of its inputs. A current flowing through the resonant circuit can then be detected as the response signal, for example, using a current sensor. However, excitation using an inductively coupled coil eliminates the need for additional sensors to detect the response signal.

[0029] According to a further advantageous embodiment of the invention, the inductive resonant circuit part is provided by a coil having a first and a second coil end, and the capacitive resonant circuit part is provided by an elongated conductor pair with two electrical conductors, a first of which is electrically connected or connectable to the first coil end, and a second of which is electrically connected or connectable to the second coil end. The two electrical conductors can be provided, for example, as individual wires, printed conductive traces, or similar. These conductors can be spaced apart from each other, in particular running substantially parallel to each other, with the space preferably being as small as possible, e.g., a maximum of a few millimeters.

[0030] The ends of the two conductors of the conductor pair that are opposite the ends connected to the respective coil ends, or connectable ends of the respective conductors, represent open ends. The elongated conductor pair can advantageously be of any length. A conductor pair that is as long as possible is particularly advantageous. An elongated design of the conductor pair has the significant advantage that the capacitive resonant circuit section can be laid over any area required for deformation detection. This allows, for example, damage monitoring for elongated battery modules with multi-cell battery components.

[0031] The fact that the first coil end is connected or connectable to the first conductor of the conductor pair means that the first conductor can either be permanently connected to the first coil end or connected situationally, for example, via a switch or similar device. The same applies to the second coil end and the second electrical conductor. However, a permanent electrically conductive connection is preferred. This simplifies the construction and design of the resonant circuit. In particular, the conductor pair and the coil can be made from a single, one-piece wire or conductor.

[0032] According to a further advantageous embodiment of the invention, the top of the protective plate comprises a first area corresponding to a battery module of the battery, wherein the first area has a width and a length greater than the width, and has a starting area and an end area with respect to the longitudinal direction of the first area, wherein the inductive resonant circuit part is arranged in the starting area and the conductor pair extends to the end area, in particular wherein the conductor pair runs in at least one loop and / or is wavy and / or zigzag-shaped and / or meandering.

[0033] The beginning and end regions of the first section of the carrier plate are thus opposite each other along the longitudinal direction of the first region. It is highly advantageous if the conductor pair extends over virtually the entire length of the first region. The conductor pair can have a length of, for example, at least one meter or several meters. This allows a particularly large area to be covered for deformation detection. The first region can, for example, have a length corresponding to the length of the associated battery module that is to be monitored by the measuring device or arrangement. This module can be positioned in a specific direction, for example, directly above the first region.

[0034] Furthermore, the conductor pair can also be configured to extend in one or more loops along the length and / or width of the first area. This increases the length of each conductor, thereby covering a larger detection area. The conductor pair does not necessarily have to run in a straight line from the start to the end area, but can, for example, run from the start to the end area, loop back to the start, and then loop back to the end again, and so on. Additionally or alternatively, the conductor pair can also run from the start to the end area in a wave-like, zigzag, or meandering pattern. This allows for even more efficient coverage of the monitored areas.

[0035] According to a further advantageous embodiment of the invention, the measuring arrangement comprises the battery, which has at least one battery module arranged above and at a distance from the first region of the protective plate in a defined direction. Thus, the resonant circuit allows an entire battery module, which in particular can again comprise several battery cells, to be monitored for the occurrence of the specific type of damage.

[0036] According to a further advantageous embodiment of the invention, the protective plate has several areas that correspond to the respective battery module in the battery, wherein the measuring arrangement comprises several measuring devices and a measuring device is arranged in each of the several areas of the carrier plate. Thus, for example, a corresponding measuring device can be provided below each battery module. In principle, it would also be possible to route the conductor pair of the measuring device in such a way that it covers the entire area of ​​the carrier plate located below the several battery modules, e.g., by looping it or similarly. However, since there are other components located on the underride guard, or mounting points or similar features are provided, the subdivision into several sub-areas is very advantageous.This allows for a corresponding measuring device with a suitable resonant circuit to be specifically positioned under each battery module. This also makes it possible to monitor the individual battery modules for specific types of damage independently of each other using their respective measuring devices. Any detected damage can then be located.

[0037] Furthermore, the invention also relates to a motor vehicle with a measuring arrangement according to the invention or one of its embodiments.

[0038] 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 be designed as an electric vehicle.

[0039] The invention also includes the control unit for the measuring arrangement. The control unit can comprise a data processing device or a processor circuit configured to perform an embodiment of the method according to the invention. For this purpose, the processor circuit 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). In particular, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an NPU (Neural Processing Unit) can be used as the microprocessor. Furthermore, the processor circuit can comprise program code configured to perform the embodiment of the method according to the invention when executed by the processor circuit.The program code can be stored in a data memory of the processor device. The processor device can be based, for example, on at least one circuit board and / or on at least one SoC (System on Chip).

[0040] Furthermore, the invention relates to a method for detecting a specific type of damage to a battery by means of an external force applied by an object to a protective plate arranged below the battery in a defined direction, the protective plate having a distance from the battery in at least a certain area, wherein the protective plate has a top surface facing the battery, comprises a measuring device and a control device coupled thereto, which determines the specific damage depending on a measurement signal detected by means of the measuring device.An electrical resonant circuit with an inductive resonant circuit part and a capacitive resonant circuit part is arranged on the top side of the protective plate, and an excitation unit is coupled to the resonant circuit, which excites the resonant circuit and detects a response signal of the resonant circuit to the excitation as the measurement signal, wherein the control device determines a resonant frequency of the resonant circuit depending on the detected response signal and detects the specific damage depending on the determined resonant frequency.

[0041] The invention also includes further developments of the method according to the invention, which have features already described in connection with the further developments of the measuring arrangement according to the invention. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0042] 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.

[0043] The following are exemplary embodiments of the invention described. This is illustrated by: Fig. 1 a schematic representation of a measuring arrangement according to an embodiment of the invention; Fig. 2 a schematic representation of a measuring arrangement with an underride guard according to an embodiment of the invention; Fig. 3 a schematic cross-sectional representation of a measuring arrangement with an underride guard and a battery according to an embodiment of the invention; Fig. 4 a schematic top view of a measuring arrangement with an underride guard according to an embodiment of the invention; Fig. 5 a schematic representation of a measuring arrangement with a battery in a normal state and a graphical representation of a response signal of the resonant circuit corresponding to this normal state according to an embodiment of the invention; and Fig. 6 a schematic representation of a measuring arrangement with a battery when the specific damage occurs and a graphical representation of a response signal of the resonant circuit corresponding to this damage according to an embodiment of the invention.

[0044] 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.

[0045] In the figures, identical reference symbols denote functionally equivalent elements.

[0046] Fig. Figure 1 shows a schematic representation of a measuring arrangement 10 according to an embodiment of the invention. The measuring arrangement 10 comprises a measuring device 12 and a control device 14. The measuring device 12 can be mounted on a flat protective plate 30 (not shown here) (see Figure 1). Fig. 2) be arranged. The measuring device 12 comprises an electrical resonant circuit 16, which has an inductive resonant circuit section 16a and a capacitive resonant circuit section 16b. The inductive resonant circuit section 16a is provided by a coil 18, and the capacitive resonant circuit section 16b by a pair of conductors 20 with two electrical conductors 20a, 20b. The coil 18 has a first coil end 18a, which is connected to the first electrical conductor 20a, and a second coil end 18b, which is electrically connected to the second conductor 20b of the pair of conductors 20. The coil 18 and the electrical conductors 20a, 20b can also be made from a single conductor, e.g., a wire or a printed conductor track or the like. The measuring device 12 also comprises an excitation unit 22. This in turn comprises an excitation coil 24.An excitation signal can be coupled into the resonant circuit 16 via the excitation coil 24, which is inductively coupled to the coil 18. Furthermore, the corresponding response signal A1, A2 can be generated by means of the excitation unit 22 (see figure). Fig. 5 and Fig. 6) after excitation of the resonant circuit 16, the signal is detected and made available to the control unit 14 for evaluation. The control unit 14 can analyze the detected response signal A1, A2 with respect to its resonant frequency F. R (cf.) Fig. 5 and Fig. 6) evaluate and compare with a reference resonance frequency RF stored in the control unit 14 R determine whether the specific damage B (cf. Fig. 6) has occurred or not. The evaluation of such a response signal A1, A2 will be discussed later in connection with Fig. 5 and Fig. 6 explained in more detail.

[0047] Fig. Figure 2 shows a schematic representation of a measuring arrangement 10 according to an embodiment of the invention. This can be, in particular, as shown in Figure 2. Fig. The measuring arrangement 10 is described in Figure 1 and is shown in a schematic side view. It comprises a protective plate 30, which is provided by an underride guard 30, on the upper surface 30a of which the measuring device 12 is arranged. The control unit 14 coupled to the measuring device 12 is not shown here for the sake of clarity. The upper surface 30a of the underride guard 30 can comprise a sub-area 32 that extends over a length L in the x-direction shown. The measuring device 12, more precisely the resonant circuit 16, can also extend over the entire sub-area 32 in the x-direction. The coil 18 is arranged in an initial region 33a of this sub-area 32, and the conductor pair 20 extends in the x-direction to the end 33b or an end region 33b of this sub-area 32.The length L can correspond to the length of a battery module 40 positioned in the z-direction above the underride guard 30 (see . Fig. 3) correspond. This advantageously allows deformation and damage monitoring to be provided over the entire length L of such a battery module 40.

[0048] Furthermore, the excitation coil 24 is also shown, which in this example is located above the coil 18 of the resonant circuit 16 in the z-direction. It is spaced apart from the resonant circuit coil 18 and is not in electrically conductive contact with it. The coil 24 is therefore electrically isolated from the resonant circuit coil 18. As can be seen, the measuring arrangement 10 allows for a design with an arbitrarily large area, but which is particularly space-saving in the z-direction.

[0049] Fig. Figure 3 shows a schematic cross-sectional view of a measuring arrangement 10 according to a further embodiment of the invention. This can again be configured as described above. In addition, the measuring arrangement 10 in this example comprises a battery 38 with several battery modules 40, in this example four battery modules 40. Each of the battery modules 40 comprises several battery cells 42, which are arranged side by side in the x-direction. The underside of the battery 38 is designated 38a. This can be provided by the modules 40 and / or cells 42 and / or by a base of a battery housing (not shown here). The underside 38a is made of a metallic material.

[0050] In particular, in the present example, a measuring device 12 is provided for each battery module 40. Each measuring device 12 can be configured as described above and accordingly comprise a resonant circuit 16 and an associated excitation unit 22. The excitation units 22 can all be connected to a common control unit 14, which, however, is not shown here for the sake of clarity. The protective plate 30, or rather its upper surface 30a, is in turn divided into several sub-areas 32a, 32b, 32c, 32d. Each sub-area 32a to 32d is assigned to a battery module 40 and is arranged directly below this battery module 40 with respect to the z-direction. Thus, a measuring device 12 is arranged in each sub-area 32a to 32d. In this way, separate deformation and damage monitoring can advantageously be provided for each battery module 40.

[0051] Fig. Figure 4 shows a schematic representation of a measuring arrangement 10 according to a further embodiment of the invention. In particular, the underride guard 30 is also shown here in a top view from above in the z-direction, i.e., on its upper surface 30a. The measuring arrangement 10 can be used, in particular, as described above. Fig. 3 described above. Here, the four measuring devices 12 with the respective resonant circuits 16 and the excitation units 22 are shown, which are located in the respective sub-areas 32a, 32b, 32c, 32d of the upper surface 30a.

[0052] Each resonant circuit 16 can generally be applied to a separate substrate, which in turn is arranged on the upper surface 30a of the underride guard 30. Alternatively, the respective resonant circuit 16 can also be applied directly to the upper surface 30a of the underride guard 30, e.g. by printing, or alternatively be integrated or embedded in the component, i.e., the underride guard 30, or similarly.

[0053] Furthermore, it can be seen here that each pair of conductors 20 extends in the x-direction in several loops. In other words, each pair of conductors 20 runs from the starting area 33a to the end area 33b and from there back towards the starting area 33a, and from there again towards the end area 33b. This increases the detection area. Alternatively or additionally, the pairs of conductors 20 can also run from the starting area 33a to the end area 33b in a wave-like, zigzag, or meandering pattern.

[0054] Fig. Figure 5 shows a schematic representation of a measuring arrangement 10 in a normal state, i.e., without any specific damage to the battery 38, and a correspondingly recorded response signal A1, in particular its amplitude A as a function of the frequency f, according to an embodiment of the invention. In this case, i.e., when there is no contact between the resonant circuit 16 and the battery 38 located above it or its metallic underside 38a, the resonance frequency F determined from the response signal A1 corresponds to R of the resonant circuit 16 essentially to the reference resonant frequency RF R , i.e., it deviates from this by less than a predefinable value.

[0055] Fig. Figure 6 shows a schematic representation of the measuring arrangement 10. Fig.5. Upon occurrence of the specific damage B to the battery 38, resulting from an external force K applied to the protective plate 30 from below by an external object 31, and the associated detectable response signal A2, which in turn represents the signal amplitude A as a function of the frequency f. In this case, the resonance frequency RF is now R no longer at the location of the reference resonance frequency RF R , but is shifted relative to it by more than the specified value, namely in this case by the change Δf, and in particular reduced. The specific damage B can now be reliably detected via this frequency shift Δf.

[0056] Overall, the examples demonstrate how the invention can provide a planar sensor unit for detecting deformation states in the vicinity of a vehicle battery, which in particular utilizes an oscillating circuit for deformation detection. For future generations of battery housings, there is a requirement to obtain as much information as possible about the battery's condition through the use of various sensors and to detect potential risks early on by monitoring the immediate battery environment. The detection of potential battery damage caused by deformations (load cases) occurring from below is also highly relevant. However, this has so far been associated with high costs and potentially low detection accuracy. The measuring arrangement according to the invention...Its embodiments enable the provision of a planar sensor variant which, in addition to deformation detection, has the potential to directly fulfill further advantageous requirements and can thus offer a very economically attractive technical alternative. The measuring arrangement can be designed to distinguish between critical and non-critical deformations in a battery environment and can be configured with a support component, namely the protective plate, and an electrical resonant circuit with a capacitive and inductive component located thereon, with a control unit and a coupling coil connected to it, and in particular an opposing component, especially the underside of the battery. The opposing component preferably has a lower resistance than the medium surrounding the component (generally air). In the normal state, the support component and the opposing component are separated.The support component can be made of plastic or metal. The electrical resonant circuit is located on the surface of the support component as a ribbon-like structure. The resonant circuit can be applied to the ribbon-like structure as a wire or alternatively printed on it. A deformation of the support component classified as "non-critical" reduces the distance to the component above it, but not to zero. A deformation of the support component classified as "critical" closes the distance to the component above it, at least for a limited time period. Maximum proximity or contact between the support component and the opposing component significantly affects the capacitive component of the resonant circuit locally and thus reduces the resonant frequency of the circuit.A reduced resonant frequency causes the control unit to classify a deformation event as "critical," triggering a corresponding action within the vehicle, such as informing the driver, issuing a workshop message, or initiating vehicle shutdown, etc. The mounting component is preferably part of the vehicle's underride guard, located as a protective structure beneath the battery. The sensitivity of the sensor unit can be significantly influenced by geometrically varying the capacitive component, for example, by adjusting the number of loops in the conductor pair, the bandwidth, etc. Signal stability can be influenced by varying the number of turns in the inductive component. Furthermore, the sensor unit may be capable of performing additional functions enabled by manipulating the capacitive component. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 206 663 A1

[0003] DE 10 2021 122 968 A1

[0004] WO 2023 / 006914 A1

[0005] DE 10 2022 117 853 A1

[0006]

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