Sensor element, in particular in the form of an SMD component

Abstract

The invention relates to a sensor element (10) for identifying liquids on a component, the sensor element (10) comprising: - a reservoir (13), in particular a salt reservoir, for providing an electrolyte-forming substance; - a first electrically conductive connection (11) for attaching the reservoir (13) to the component and for electrically contacting a first conductor track (L1); and - a second electrically conductive connection (12) for attaching the reservoir (13) to the component and for electrically contacting a second conductor track (L2).

Description

[0001] Description

[0002] Sensor element, particularly in the form of an SMD component

[0003] The invention relates to a sensor element, in particular in the form of an SMD component, for detecting liquids on a component, for example, on a circuit board or on a housing part. Furthermore, the invention relates to a corresponding sensor unit for sensing liquids with a corresponding sensor element. Furthermore, the invention relates to a corresponding circuit board for a control unit of a steering system and / or a battery system of a vehicle with a corresponding sensor unit. Furthermore, the invention relates to corresponding uses of a sensor element according to the invention and a circuit board according to the invention. Furthermore, the invention relates to a vehicle with a corresponding sensor unit.

[0004] Future steering systems will increasingly have to meet very high requirements regarding their failure rate. This is due to highly automated driver assistance functions as well as by-wire systems, such as steer-by-wire systems, which do not provide a mechanical fallback layer. Such systems require a high degree of self-diagnosis and error detection. The ingress of water can lead to partial or complete failure of the steering system. Water can cause a short circuit in the sensors or on the circuit boards and lead to the immediate failure of a subsystem or even the entire steering system. Furthermore, corrosion of metallic / mechanical components can also render the steering system inoperable after a certain period of time. Therefore, the detection of water ingress is of great importance for future steering systems. Sensors for detecting liquids based on a resistive measuring principle are known.However, this requires the water to be sensed to have a certain conductivity, which is not present in rain and puddle water.

[0005] The object of the invention is therefore to provide an improved sensor element for detecting liquids, in particular on printed circuit boards. In particular, the object of the invention is to provide a sensor element that can be designed simply and cost-effectively, that can be manufactured, assembled, and mounted on a component, e.g., on a printed circuit board or on a housing part, easily and without great effort, and that enables the quick, safe, and reliable detection of the ingress of liquids, such as rainwater and puddle water, on a component, e.g., on a printed circuit board or on a housing part. Furthermore, the object of the invention is to provide a corresponding sensor unit, a corresponding printed circuit board, and a corresponding vehicle.

[0006] The problem is solved by a sensor element, in particular in the form of an SMD component, for detecting liquids on a component, e.g., on a circuit board or on a housing part, having the features of the independent device claim. Furthermore, the invention relates to a corresponding sensor unit for sensing liquids, having a corresponding sensor element, having the features of the independent device claim. Furthermore, the invention relates to a corresponding circuit board for a control unit of a steering system and / or a battery system of a vehicle, having a corresponding sensor unit, having the features of the independent device claim. Furthermore, the invention relates to uses of a sensor element according to the invention and a circuit board according to the invention, having the features of the independent use claims.Furthermore, the invention relates to a vehicle with a corresponding sensor unit having the features of the independent device claim. Features described in connection with individual aspects and / or embodiments of the invention naturally also apply in connection with the other aspects and / or embodiments, and vice versa, so that with regard to the disclosure of the individual aspects and / or embodiments of the invention, reference is always made to each other.

[0007] The invention provides: a sensor element, in particular in the form of an SMD component, for detecting liquids on a component, for example on a printed circuit board or circuit board or on a housing part, the sensor element comprising: a depot, in particular a salt depot, for providing an electrolyte-forming substance, in particular a salt, a first electrically conductive connection for fastening the depot to the component, for example on the printed circuit board or on the housing part, and for electrically contacting a first conductor track and a second electrically conductive connection for fastening the depot to the component, for example on the printed circuit board or on the housing part, and for electrically contacting a second conductor track.

[0008] A salt deposit can advantageously comprise at least one salt or several salts. Salts within the scope of the present disclosure can be understood as chemical compounds that have positively charged cations and negatively charged anions that electrostatically attract each other, thus creating chemical bonds. The term "water" within the scope of the present disclosure is used for various liquids, for example, for weather-related liquids, such as rain and / or puddle water, and / or for technical liquids, such as cooling fluids, lubricating fluids, etc.

[0009] The invention provides an SMD component (SMD stands for "Surface Mount Device") using the sensor element. The inventive idea lies in the use of a depot, in particular a salt depot, as an SMD component. The depot can be formed, for example, in the form of a tablet, preferably comprising a pressed powder, such as salt powder. The depot is preferably provided with, for example, solderable contacts as electrically conductive connections. The depot, in particular a salt depot, has defined electrical properties as an SMD component, in particular a defined electrical resistance (in the range of several kOhms, accuracy + / - 100 Ohms). The conductivity of the water that comes into contact with the salt depot is significantly increased. Such a component is also cold- and heat-resistant (-40°C - +120°C). 0 C).

[0010] An electrically conductive structure can also be integrated into the depot. This electrically conductive structure can advantageously serve as a stabilizing support for the pressed salt. Furthermore, the electrically conductive structure can represent a sensor structure. However, the electrically conductive structure can also provide a defined electrical resistance. This enables diagnosis of the condition of the salt depot.

[0011] Furthermore, the salt reservoir can be held in place in some kind of enclosing holder (cage / housing) to stabilize the reservoir if necessary and / or to facilitate its attachment to the circuit board. In this case, the sensor element is also implemented as an SMD component.

[0012] Such a sensor element has several advantages:

[0013] Simple, automated integration on a circuit board (established methods for integrating SMD components can be used). Self-diagnosis is possible because the electrical properties of the sensor element are known and the sensor element is electrically connected to the circuit board. No additional mounting / fixing for the salt reservoir is required. Penetrated water can be detected quickly, safely, and reliably. Advantageously, the sensor element can be positioned relatively close to a measuring unit, which can be implemented using a resistive measuring principle (i.e., resistance measurement) for simplicity.

[0014] A measuring unit can sense the resistance or the voltage applied between the conductor tracks. The measuring unit can, for example, contain a voltage divider and measure the voltage across defined measuring points. Established methods for voltage / resistance measurement can be used. For simplicity, this is referred to as a resistance measurement between the conductor tracks. The measured voltages can be evaluated directly in the measuring unit or by a central processing unit.

[0015] At least one or more sensor elements can be provided on a component, such as a printed circuit board, which can be connected, for example, to a measuring unit. Such sensor elements can be used advantageously to detect liquids on components, preferably on printed circuit boards or circuit boards, which in turn can be used in control units, for example in steering systems and / or braking systems, particularly in steer-by-wire systems and / or break-by-wire systems where no mechanical fallback level is provided, and / or in battery systems, such as power packs, high-voltage batteries, traction batteries, low-voltage batteries, auxiliary batteries, etc.

[0016] As mentioned above, it can be advantageous for the sensor element to be implemented as an SMD component. This allows the sensor element to be mounted and electrically contacted on a component, such as a circuit board, using established methods for SMD components.

[0017] Furthermore, it is conceivable that the depot could be designed in the form of a tablet. This would provide a simple and cost-effective component for detecting water.

[0018] Furthermore, it is conceivable for the reservoir to contain a compressed, powdery electrolyte-forming substance, particularly salt. This allows the reservoir to easily absorb water, such as rainwater and puddle water. Consequently, the reservoir can be advantageously used for resistance measurement to detect water ingress in a simple, safe, and reliable manner.

[0019] Furthermore, it can be provided that the first electrically conductive connection can have a first contact element, in particular in the form of a solder joint, preferably comprising tin, and / or that the second electrically conductive connection can have a second contact element, in particular in the form of a solder joint, preferably comprising tin. In this way, the sensor element can be provided and used as an SMD component in a structurally simple and cost-effective manner.

[0020] As mentioned above, the component can preferably be implemented as a printed circuit board. This allows the sensor element to be mounted on the circuit board and electrically contacted using established methods for SMD components.

[0021] Advantageously, it can further be provided that the depot can have a first, in particular one-piece, preferably integrally formed, electrically conductive structure with a first defined electrical resistance (relatively high and easily measurable resistance). The first electrically conductive structure can be electrically contacted with the first conductor track and the second conductor track. The depot can be pressed around the structure. Self-diagnoses of the sensor element can be carried out using the first electrically conductive structure. The first resistance can be measured at defined time intervals or sampling rates. If the first resistance is within a defined range, there is no water on the conductor tracks or in the depot.

[0022] The first electrically conductive structure can, for example, be sinusoidal, meandering, and / or grid-shaped. On the one hand, such an electrically conductive structure can adjust the first resistance as desired. On the other hand, such an electrically conductive structure can enable a stabilizing and / or holding function for the depot.

[0023] According to a further advantage, the depot can have a second, in particular two-part, preferably integrally formed, electrically conductive structure with a second defined electrical resistance (comparatively low resistance). The second electrically conductive structure can have a first substructure and a second substructure, which can be arranged separately (meaning galvanically isolated) and / or spaced apart from one another, in particular within the depot. The first substructure can be electrically contacted with the first conductor track, and the second substructure can be electrically contacted with the second conductor track. The depot can be pressed around the structure.

[0024] The first substructure and the second substructure can preferably be comb-shaped and / or herringbone-shaped and / or interlocking. The second electrically conductive structure can serve as a carrier for the minerals and, through a comb-like and / or herringbone-like, interlocking arrangement of two conductors, form an advantageous measuring structure for the resistive sensor. The sensor is initially protected from small amounts of water, such as condensation, by the salt deposit and is short-circuited when the salt deposit dissolves in the water.

[0025] Furthermore, it is conceivable that the depot could be housed in a holder (cage / housing), e.g., made of a non-electrically conductive material. This can provide a secure fixation for the depot. Mounting the sensor element on the component, such as the circuit board, can also be simplified.

[0026] As already mentioned above, the invention provides: a use of a sensor element, which can be designed as described above, as an SMD component.

[0027] Furthermore, the invention provides: a sensor unit for sensing liquids, comprising: at least one or more sensor elements, which can be designed as described above, and a measuring unit for detecting an electrical resistance between the first conductor track and the second conductor track.

[0028] The sensor unit according to the invention can achieve the same advantages as those described above in connection with the sensor element according to the invention. These advantages are incorporated herein by reference.

[0029] Furthermore, the invention provides: a printed circuit board with a corresponding sensor unit, in particular for a control unit of a steering system and / or a battery system of a vehicle.

[0030] The circuit board according to the invention can achieve the same advantages as those described above in connection with the sensor element according to the invention. These advantages are incorporated herein by reference.

[0031] Furthermore, the invention provides: a use of a corresponding circuit board for a control unit of a steering system and / or a battery system of a vehicle.

[0032] The invention also provides: a vehicle with at least one corresponding sensor unit. The vehicle according to the invention can achieve the same advantages as those described above in connection with the sensor element according to the invention. These advantages are incorporated herein by reference. Furthermore, the invention is illustrated in more detail with reference to the figures. It should be noted that the figures are merely descriptive and are not intended to limit the invention in any way. They show:

[0033] Fig. 1 is an exemplary representation of a circuit board, a sensor unit and a sensor element within the scope of the present disclosure,

[0034] Fig. 2 is an exploded view of a sensor element within the scope of the present disclosure,

[0035] Fig. 3 is an exemplary representation of sensor elements within the scope of the present disclosure,

[0036] Fig. 4 is an exemplary representation of sensor elements within the scope of the present disclosure, and

[0037] Fig. 5 is an exemplary representation of sensor elements within the scope of the present disclosure.

[0038] Fig. 1 shows a sensor unit 100, which can have at least one or more sensor elements 10, in particular in the form of SMD components, which are provided for detecting liquids on a component, preferably on a printed circuit board 101 or circuit board or on a housing part.

[0039] The sensor element 10 or in each case a sensor element 10 has: a depot 13, in particular a salt depot, for providing an electrolyte-forming substance, in particular a salt, a first electrically conductive connection 11 for fastening the depot 13 on the component, such as the circuit board 101, and for electrically contacting a first conductor track L1 and a second electrically conductive connection 12 for fastening the depot 13 on the component, such as the circuit board 101, and for electrically contacting a second conductor track L2.

[0040] A depot 13, in particular a salt depot, within the scope of the invention can contain at least one electrolyte-forming substance, such as salt or multiple salts. The invention provides an SMD component or part (SMD stands for "surface-mount device") with the aid of the sensor element 10.

[0041] As indicated in Figure 2, the depot 13 can be in the form of a tablet, for example, from a compressed powder, such as salt powder. The electrolyte-forming substance or the salt component in the depot 13 is advantageously soluble in water.

[0042] As Fig. 2 and Fig. 5 on the left also indicate, the depot 13 can be provided as a solid component. Such a component can advantageously retain its shape and be easily processed, particularly for attaching and contacting the depot 13 to the component, such as the printed circuit board 101.

[0043] As an SMD component, Depot 13 exhibits defined electrical properties, particularly a defined electrical resistance (in the range of several kOhms, accuracy + / - 100 Ohms). The conductivity of water that comes into contact with Depot 13 is significantly increased. Such a component is also cold- and heat-resistant (-40°C - +120°C).

[0044] When water penetrates depot 13, depot 13 enriches the water with salts / minerals. This makes the incoming water highly conductive. The resistance between the conductors L1 and L2 decreases significantly.

[0045] As illustrated in Figures 1 and 3 to 5, the depot 13 is placed between the conductor tracks L1 and L2 and is electrically connected to each of the conductor tracks L1 and L2, for example, via a solder connection. This establishes a defined electrical resistance between the conductor tracks L1 and L2.

[0046] A measuring unit 20, shown schematically in Fig. 1, can sense the resistance and / or the voltage applied between the conductor tracks L1, L2. The measuring unit 20 can use established methods for voltage / resistance measurement. The measurements can be evaluated directly in the measuring unit 20 or by a central control unit.

[0047] As Fig. 1 also illustrates, at least one or more sensor elements 10 can be provided on the component, such as on the circuit board 101, which can be connected, for example, to a measuring unit 20. Multiple sensor elements 10 can contribute to the improved detection of liquids. Such sensor elements 10 can be used advantageously to detect liquids on components, preferably on circuit boards 101 or printed circuit boards or on housing parts in general, which can be used specifically in control units, for example in steering systems and / or braking systems, in particular in steer-by-wire systems and / or brake-by-wire systems, and / or in battery systems, such as power packs, high-voltage batteries, traction batteries, low-voltage batteries, auxiliary batteries, etc.

[0048] As Figure 3 further illustrates, the depot 13 can have a first, in particular one-piece, preferably integrally formed, electrically conductive structure S1 with a first defined electrical resistance R1 (a comparatively high and easily measurable resistance, which can be provided, for example, by a relatively long and / or thick line). The first electrically conductive structure S1 can be electrically contacted with the first conductor track L1 and the second conductor track L2. The depot 13 can be pressed around the first electrically conductive structure S1.

[0049] The first electrically conductive structure S1 can be used for self-diagnosis of the sensor element 10. The first resistor R1 can be measured at defined time intervals or sampling rates. If the first resistor R1 is within a specified range, then there is no water on the conductor tracks L1, L2 or in the depot 13. If water, even with low conductivity, now comes into contact with the component, such as the circuit board 101, there is initially no short circuit between the conductor tracks L1, L2 and the water is not initially detected. This is advantageous to prevent false sensor responses from, for example, harmless condensation. If the water comes into contact with the depot 13, the depot 13 dissolves and enriches the water with minerals. The conductivity of the water increases and a short circuit between the conductor tracks L1, L2 is detected. It may be sufficient if one (e.g. of the several) depot 13 is dissolved in water.By using multiple depots 13, the concept can be made more robust.

[0050] The first electrically conductive structure S1 can, for example, be sinusoidal, meandering, and / or grid-shaped. Such an electrically conductive structure S1 allows, on the one hand, the first resistor R1 to be adjusted as desired. On the other hand, such an electrically conductive structure S1 can enable a stabilizing and / or holding function for the depot 13.

[0051] As Figure 4 further illustrates, the depot 13 can have a second, in particular two-part, preferably integrally formed, electrically conductive structure S2 with a second defined electrical resistance R2 (comparatively low resistance). The second electrically conductive structure S2 can have a first partial structure T1 and a second partial structure T2, which can be arranged separately and / or spaced apart from one another, in particular within the depot 13. The first partial structure T1 can be electrically contacted with the first conductor track L1 and the second partial structure T2 with the second conductor track L2. The depot 13 can be pressed around the second electrically conductive structure S2.

[0052] The first substructure T1 and the second substructure T2 can, for example, be comb-shaped and / or herringbone-shaped and / or interlock with each other. The second electrically conductive structure S2 can, on the one hand, serve as a carrier for the minerals and, on the other hand, form the actual structure of the resistive sensor through a comb-like and / or herringbone-like and interlocking arrangement of two conductors. The sensor element 10 is initially protected from small amounts of water, such as condensation, by the salt deposit and is short-circuited when the salt deposit dissolves in the water.

[0053] As Figure 5 illustrates on the right, the depot 13 can be accommodated in a holder 14 (cage / open housing), e.g., made of a non-electrically conductive material. This provides a fixation for the powdered material of the depot 13. This also simplifies the attachment of the depot 13 to the component, such as the circuit board 101. However, even in this case, the sensor element 10 is provided as an SMD component.

[0054] As Figures 3 and 4 show on the right-hand side, the holder 14 can be combined with a one-part electrically conductive structure S1 or with a two-part electrically conductive structure S2.

[0055] A corresponding sensor unit 100 also represents an aspect of the invention, which is designed for sensing liquids and which comprises: at least one or more sensor elements 10, which can be designed as described above, and a measuring unit 20 for detecting an electrical resistance between the first conductor track L1 and the second conductor track L2.

[0056] A corresponding circuit board 101 with a corresponding sensor unit 100 also represents an aspect of the invention, which can be used in particular for a control unit of a steering system and / or a battery system of a vehicle.

[0057] A corresponding vehicle with at least one corresponding sensor unit 100 also represents an aspect of the invention. The above description of the figures describes the present invention exclusively within the scope of examples. Of course, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the invention.

[0058] List of reference symbols

[0059] 100 sensor unit

[0060] 101 Circuit Board

[0061] 10 Sensor element

[0062] 11 electrically conductive connection

[0063] 12 electrically conductive connection

[0064] 13 Depot

[0065] 14 Bracket

[0066] 20 measuring units

[0067] L1 conductor track

[0068] L2 conductor track

[0069] 51 Structure

[0070] R1 resistor

[0071] 52 Structure

[0072] R2 resistor

[0073] T1 substructure

[0074] T2 substructure

Claims

Claims: Sensor element (10) for detecting liquids on a component, the sensor element (10) comprising: a reservoir (13), in particular a salt reservoir, for providing an electrolyte-forming substance; a first electrically conductive connection (11) for attaching the reservoir (13) to the component and for electrically contacting a first conductor (L1); and a second electrically conductive connection (12) for attaching the reservoir (13) to the component and for electrically contacting a second conductor (L2). Sensor element (10) according to claim 1, wherein the sensor element (10) is designed in the form of an SMD component, and / or wherein the reservoir (13) is designed in the form of a tablet, and / or wherein the reservoir (13) comprises a compressed powdered electrolyte-forming substance, in particular salt, and / or wherein the component is designed in the form of a printed circuit board (101).Sensor element (10) according to one of the preceding claims, wherein the first electrically conductive connection (11) comprises a first contact element, in particular in the form of a solder joint, preferably comprising tin, and / or wherein the second electrically conductive connection (12) comprises a second contact element, in particular in the form of a solder joint, preferably comprising tin. Sensor element (10) according to one of the preceding claims, wherein the reservoir (13) comprises a first, in particular one-piece, preferably integrally formed, electrically conductive structure (S1) with a first defined electrical resistance (R1), wherein in particular the first electrically conductive structure (S1) is electrically contacted with the first conductor (L1) and the second conductor (L2), wherein preferably the first electrically conductive structure (S1) is sinusoidally, meanderingly and / or lattice-shaped. Sensor element (10) according to one of the preceding claims, wherein the reservoir (13) has a second, in particular two-part, preferably integrally formed, electrically conductive structure (S2) with a second defined electrical resistance (R2), wherein in particular the second electrically conductive structure (S2) has a first substructure (T1) and a second substructure (T2) which are arranged separately and / or spaced apart from each other, in particular within the reservoir (13), wherein preferably the first substructure (T1) is electrically contacted with the first conductor (L1) and the second substructure (T2) is electrically contacted with the second conductor (L2), wherein preferably the first substructure (T1) and the second substructure (T2) are designed in a comb-like and / or herringbone shape and / or interlock with each other.Sensor element (10) according to any one of the preceding claims, wherein the reservoir (13) is received in a holder (14), in particular made of a non-electrically conductive material. Use of a sensor element (10) according to any one of the preceding claims as an SMD component. Sensor unit (100) for sensing liquids, comprising: at least one sensor element (10) according to any one of the preceding claims, and a measuring unit (20) for detecting an electrical resistance between the first conductor (L1) and the second conductor (L2). Printed circuit board (101) with a sensor unit (100) according to the preceding claim, in particular for a control unit of a steering system and / or a battery system of a vehicle. Use of a printed circuit board (101) according to the preceding claim for a control unit of a steering system and / or a battery system of a vehicle. Vehicle with at least one sensor unit (100) according to any one of the preceding claims.

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