Device for detecting moisture intrusion

Abstract

The invention relates to a device (1) for detecting moisture intrusion in a housing (2) having high-pressure components. The invention is characterized in that a gas or pressure-generating element (3) is provided which, when contacting a liquid in the form of a droplet, causes the generation of a gas or pressure, the gas or pressure sensor (4) being arranged together with the gas or pressure-generating element (3) in the same shroud element (5), and the shroud element (5) being connected to the housing (3) via at least one inlet (6), wherein the gas or pressure sensor (4) detects a pressure rise or a gas generation in the shroud element (5) and outputs a warning signal.

Description

Technical Field

[0001] The invention relates to a device for detecting moisture ingress in a housing with high-voltage components of the type defined in more detail in the preamble of claim 1 . Background Art

[0002] In principle, devices for detecting moisture ingress are known in the prior art. Such devices can detect moisture ingress in housings with high-voltage components. High-voltage components can be, for example, drive circuit components of a vehicle, such as chargers, power electronics or electric motors or electronic machines. In addition, they can also be housings of high-voltage batteries used in electric or hybrid vehicles. For all these components, even small amounts of moisture accumulation in the form of water droplets can lead to dangerous situations, in particular due to unexpected leakage currents or electrical short circuits.

[0003] A pressure and / or humidity measuring device is known from DE 10 2018 117 349 A1. Pressure and humidity can be measured by at least one sensor comprising a capacitor and at least two electrodes. At least one dielectric layer is arranged between the electrodes. At least one electrode and / or dielectric layer is arranged on the side facing away from the substrate. In this case, at least one electrode and / or dielectric layer is arranged laterally between the substrate and the moisture layer. In this way, liquid reaching the dielectric layer causes a change in capacitance, and the liquid can be measured by the capacitive humidity sensor.

[0004] These and other known systems are able to detect liquids, for example by closing electrical contacts, as long as a liquid or a medium is present between two contact surfaces. For detecting water ingress, the electrical conductivity of the water is therefore primarily used as a detection principle. Such devices, which are also called water detectors, are usually only able to reliably detect water ingress when a certain amount of water and sufficient electrical conductivity are reached.

[0005] If only a few drops of water are present, the ingress of moisture is difficult to detect or almost impossible to detect, because these drops must be located exactly on the electrical contacts of the sensor or, in the case of conductivity measurement, must fill the measuring space between the electrodes. If water penetrates into a component in the form of moisture, for example, a liquid phase is formed by condensation. The conductivity of this liquid phase is very low and is therefore very difficult to detect electrically.

[0006] Another option is to use pressure sensors to detect high-temperature events in the event of a malfunction in a battery cell. Such pressure sensors can detect pressure fluctuations in a time-resolved manner, but have not been suitable so far for detecting small amounts of liquid that have penetrated into a leaky housing. Summary of the invention

[0007] The object of the present invention is to provide a moisture intrusion detection device which overcomes the above-mentioned disadvantages.

[0008] This object is achieved according to the invention by a device having the features of claim 1, in particular in the characterizing part of claim 1. Advantageous embodiments and developments are specified in the dependent claims.

[0009] The gas or pressure generating element forms the core of the device according to the invention, which upon contact with the liquid in the form of droplets causes the generation of gas or pressure, wherein the gas or pressure sensor is arranged together with the gas or pressure generating element in the same envelope element, and the shield element is connected to the housing via at least one inlet, wherein the gas or pressure sensor detects a pressure increase or gas generation in the shield element and outputs a warning signal. The inlet can be an intermittent support structure on the housing. Advantageously, it can be a plurality of small-area holes that lead into the interior of the housing.

[0010] For example, in one embodiment, a pressure sensor already located in the housing is used to detect a pressure increase due to a high temperature event of a high-voltage component, and a gas or pressure sensor located in a shield element can be added to it, the shield element having at least one inlet to the interior of the housing. The gas or pressure generating element can be a chemical gas or pressure generating element, which reacts when it comes into contact with a liquid in the form of droplets. The shield element itself thus forms a kind of housing, so that a pressure increase or a gas pressure increase can be achieved in a confined space and can be detected.

[0011] The device is designed to detect moisture ingress in housings with high-voltage components. The housing may be, for example, a battery housing. The device can also be arranged on any component that is threatened by water ingress, especially in the form of water droplets. These may be, for example, control units, power electronics or electric drives.

[0012] Preferably, the pressure increase or gas generation can have a gradient that is different from that of a high temperature event. By means of the design of the gas or pressure generating element, a certain amount of gas can be generated, which leads to a sharp, i.e. very noticeable, pressure increase in the shield element. A gas or pressure sensor can detect this pressure increase. In this case, the gas pressure increase preferably has a large gradient, so that it can be distinguished from the gradient of a high temperature event.

[0013] According to a particularly advantageous improved design, it can be provided that the gas or pressure generating element has a water-soluble covering layer. This can prevent aging processes of the gas or pressure generating element. In this way, it is possible to avoid contact between the ambient atmosphere and the reactive substances of the gas or pressure generating element. The water-soluble covering layer can contain or consist of water-soluble salts, in particular chlorides, organic substances, in particular sugars and / or glues, in particular shellac. When in contact with a liquid substance, in particular water, the covering layer can dissolve, thereby achieving a reaction of the gas or pressure generating element to produce gas.

[0014] Here, according to an advantageous design, the gas or pressure generating element may contain a salt compound based on carbonate and / or bicarbonate. Such chemical gas or pressure generating element can trigger a violent gas generation when in contact with a liquid. In particular, it may contain a mixture of the above salt compound and a salt of a water-soluble acid (in particular an organic acid salt, such as formates, acetates or citrates).

[0015] In another advantageous embodiment, the cover element is provided with a balancing hole which opens into the housing. The balancing hole can be arranged at any position on the cover element.

[0016] Here, according to an advantageous design, it can be designed that the gas or pressure generating element is arranged in a structural recess on the housing. In this way, even when the total amount of liquid is small, the droplets that appear can be gathered in the structural recess or guided into the structural recess by gravity and / or dynamic forces during operation. In this way, the liquid in the form of droplets that appear can be detected very early.

[0017] In another preferred design, the gas or pressure generating element and the gas or pressure sensor are arranged in two sub-areas of the shield element. In this way, for example, the gas or pressure sensor can be arranged spatially separately from the gas or pressure generating element. Here, the gas or pressure generating element can be arranged at a position that is susceptible to moisture or a position that is particularly easy for water drops to reach. Conversely, the gas or pressure sensor can be arranged at another position that is specially protected against moisture or liquid droplet generation.

[0018] In another preferred embodiment, the sub-areas are connected to each other via at least one pipeline. This ensures that the increased pressure or gas pressure is equally pronounced in all sub-areas. The pipeline can establish a gas flow guide and / or a pneumatic connection between the sub-areas.

[0019] Here, according to an advantageous design, the gas or pressure sensor can be arranged in a region that is elevated relative to the upper edge of the housing, so that the gas or pressure sensor can be prevented from being damp and then damaged.

[0020] In another embodiment, at least one further sensor can be included to measure the carbon dioxide and / or residual oxygen content. In this way, high temperature events caused by the decomposition of oxygen and the formation of carbon dioxide can be detected in the housing, in particular on battery cells. In addition, the carbon dioxide generated by the gas or pressure generating element or the displacement of oxygen in the air caused by it can also be detected. This function can also be integrated into the gas or pressure sensor. For example, in the event of a high temperature event, it can be ensured that the event is detected by the sensor through the inlet or the balancing hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further advantages of the device according to the invention are given further by the remaining dependent claims and become apparent from the following description of an embodiment in more detail with reference to the attached drawings.

[0022] in:

[0023] Figure 1 A possible embodiment of the device is shown;

[0024] Figure 2 Another possible embodiment of the device is shown;

[0025] Figure 3 Another possible embodiment of the device is shown. DETAILED DESCRIPTION

[0026] Figure 1 A possible embodiment of the device 1 is shown in the figure. In this embodiment, a gas or pressure sensor 4 is arranged in the upper area of ​​the interior of the shield element 5 designed in the form of a cover, and a gas or pressure generating element 3 is arranged in the bottom area. The gas or pressure generating element 3 is directly connected to at least one inlet 6, which establishes a connection to the housing 2, in which high-pressure components are arranged. In the upper area, a balancing hole 8 is arranged on the shield element 5. Embodiments without this balancing hole 8 are also conceivable. As soon as water penetrates in the form of droplets, the gas or pressure generating element 3 will react and a sharp pressure increase will occur inside the shield element 5. The sensor 4 can detect this. Once such an event is detected, a targeted message can be output, for example to the driver or operator.

[0027] Figure 2 Another embodiment of the device 1 can be seen in FIG. Here, the same parts have the same reference numerals and no detailed description is required. Figure 1Differently, the combination shown here has structurally mounted the sensor on the housing 2 or the circuit board. The shield element 5 can be designed as a top cover of a conventional sensor. A partition 13 is provided inside the shield element 5, which can prevent water from directly contacting the gas or pressure sensor 4. In this way, the shield element 5 can be divided into two sub-areas.

[0028] Figure 3 Another embodiment of the device 1 is shown, in which the gas or pressure sensor 4 is arranged in an area that is elevated relative to the upper edge 12 of the housing. In this way, the sensor 4 can be protected at least temporarily from possible liquid contact. In this embodiment, the gas or pressure generating element 3 is arranged separately from the sensor 4. The shield element 5 therefore has different sub-areas 10, which are connected to each other via lines 11. These lines 11 are gas flow guides and / or pneumatic connections and can be formed by pipes or hoses. Optionally, one of the gas or pressure sensors 4 can be arranged in a structural recess 9 on the housing 2. In this way, droplets can accumulate in this area due to gravity and / or dynamic forces during operation, so that a warning can be output even when the total amount of liquid is small.

[0029] certainly, Figures 1 to 3 The embodiments of the device 1 described in the embodiment can also be combined with each other, so as to produce different possibilities. Figure 3 The embodiment of the present invention may not install the gas or pressure generating element 3 in the recess. For example, this embodiment may also have only two sub-areas 10. In addition, the shield element 5 is of course not limited to the shape shown.

[0030] The proposed device 1 can therefore protect high-voltage components in particular from leakage currents and short circuits. The user can also be protected from cross-circuit faults on accessible surfaces. In the case of liquids in the form of droplets, since a warning is triggered even in the case of very small amounts, high-value components, in particular batteries or electric drives, can be protected or dried and repaired before they become unusable. If the existing sensors in the battery are used for detection, the device can be further designed in a cost-effective manner. Retrofitting for series production models is also conceivable.

Claims

1. A device (1) for detecting moisture ingress in a housing (2) with high-voltage components, characterized in that A gas or pressure generating element (3) is provided, which causes the generation of gas or pressure when it contacts a liquid in the form of droplets, wherein a gas or pressure sensor (4) is arranged together with the gas or pressure generating element (3) in the same shield element (5), and the shield element (5) is connected to the housing (3) via at least one inlet (6), wherein the gas or pressure sensor (4) detects a pressure increase or gas generation in the shield element (5) and outputs a warning signal.

2. The device (1) according to claim 1, It is characterized in that Pressure rise or gas generation has a different gradient than a high temperature event.

3. The device (1) according to claim 1 or 2, It is characterized in that The gas or pressure generating element (3) has a water-soluble covering layer (7).

4. The device (1) according to any one of claims 1 to 3, It is characterized in that The gas or pressure generating element (3) contains a carbonate and / or bicarbonate based salt compound.

5. The device (1) according to any one of claims 1 to 4, It is characterized in that The shield element (5) has a balancing hole (8) leading to the interior of the housing (2).

6. The device (1) according to any one of claims 1 to 5, It is characterized in that The gas or pressure generating element (3) is arranged in a structural recess (9) on the housing (2).

7. The device (1) according to any one of claims 1 to 6, It is characterized in that The gas or pressure generating element (3) and the gas or pressure sensor (4) are arranged in two sub-regions (10) of the shield element (5).

8. The device (1) according to claim 7, It is characterized in that The sub-regions (10) are connected to one another via at least one pipeline (11).

9. The device (1) according to any one of claims 7 or 8, It is characterized in that The gas or pressure sensor (4) is arranged in a region which is elevated relative to an upper edge (12) of the housing.

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