Moisture Detection in an Electronic Switching Circuit

Abstract

The moisture detection device (2) of the electronic switch circuit (1) has a conductive detection structure (3) in the environment of a conductive first reference structure (4a). The moisture detection device (2) has a voltage sensor (5) which can be connected to the detection structure (3) and to a conductive second reference structure (4b). The voltage sensor (5) is designed to generate a sensor signal based on the voltage between its sensor terminals (6a, 6b). The switching means (8, 10) of the moisture detection device (2) are designed to selectively disconnect the voltage sensor (5) from the second reference structure (4b) and to connect it to the second reference structure. The evaluation unit (7) of the moisture detection device (2) is designed to detect moisture based on the sensor signal.

Description

Field of the Invention

[0001] The present invention relates to an electronic switching circuit having a moisture detection device, a battery pack for supplying such an electronic switching circuit to an electronic device, an electronic device having such an electronic switching circuit or battery pack, and a method for detecting moisture in the electronic switching circuit. Background Art

[0002] Moisture entering an electronic switching circuit can cause malfunctions and damage to the electronic switching circuit or the device including the electronic switching circuit. When an exemplary damaged lithium-ion battery cell comes into contact with water, this can have a particularly dramatic effect, which can lead to violent reactions and thus also to personal injury. Summary of the Invention

[0003] The object of the present invention is to enable simple and reliable detection of moisture in an electronic switching circuit.

[0004] This object is solved by the respective subject matter of the independent claims. Advantageous further developments and preferred embodiments are the subject matter of the dependent claims.

[0005] The present invention is based on the idea that in addition to two reference structures connected to the respective reference potential terminals of the electrical switching circuit, a detection structure is provided and the voltage between the detection structure and one of the reference structures is measured in order to detect moisture between the detection structure and the other reference structure.

[0006] According to one aspect of the present invention, there is provided an electronic switch circuit including a moisture detection device. The moisture detection device has a conductive detection structure disposed in the ambient environment of a conductive first reference structure of the electronic switch circuit, wherein the first reference structure is connected to a first reference potential terminal of the electronic switch circuit. The moisture detection device has a voltage sensor having a first sensor terminal and a second sensor terminal, the first sensor terminal being connected to the detection structure, and the second sensor terminal being connectable to a conductive second reference structure of the electronic switch circuit. Here, the second reference structure is connected to a second reference potential terminal of the electronic switch circuit. The voltage sensor is designed to generate a sensor signal based on the voltage between the first sensor terminal and the second sensor terminal. The moisture detection device has a switching device designed to selectively disconnect the second sensor terminal from the second reference structure and connect it to the second reference structure. In other words, the switching device is designed to switchably connect the second sensor terminal to the second reference structure or connect and disconnect the second sensor terminal from the second reference structure. The moisture detection device has an evaluation unit designed to detect moisture based on the sensor signal generated especially during the period when the second sensor terminal is electrically connected to the second reference structure through the switching device, and the moisture electrically couples the first reference structure and the detection structure.

[0007] The first and second reference potential terminals are especially at different potentials. The first and second reference potential terminals of the electronic switch circuit can be used, for example, to connect the electronic switch circuit to a voltage source, such as one or more battery units. Alternatively, the first reference potential terminal can be connected to the supply voltage for the electronic switch circuit, and the second reference potential terminal can be connected to the ground terminal, or vice versa. The first reference structure is directly or indirectly electrically connected to the first reference potential terminal, and similarly the second reference structure is directly or indirectly electrically connected to the second reference potential terminal. The reference structure can be, for example, a wire connection, a conductor circuit, a terminal or pin of an electronic component, an electrode, etc. By the direct or indirect connection of each reference structure to the corresponding reference potential terminal, it is especially ensured that the reference structure is at a defined potential accordingly.

[0008] The detection structure can also be, for example, a conductor circuit, a wire structure or other conductive structure, which is especially not significant for the functionality of the electronic switch circuit other than moisture detection. In particular, in the dry state of the electronic switch circuit, that is, when moisture does not couple the detection structure to the first or second reference structure and the second sensor terminal is disconnected from the second reference structure, the detection structure is neither directly nor indirectly connected to one of the reference potential terminals. Therefore, the potential of the detection structure is usually not fixed or floating.

[0009] The sensor signal is in particular a direct measure of the voltage between the first and second sensor terminals. Thus, if the switching device electrically connects the second sensor terminal to the second reference structure, the sensor signal is a direct measure of the voltage between the sensing structure and the second reference structure.

[0010] It is understandable that moisture electrically couples the first reference structure to the sensing structure, in particular in such a way that the moisture at least temporarily establishes an electrical connection between the first reference structure and the sensing structure.

[0011] Due to the floating potential of the sensing structure when the circuit is in a dry state, there is a voltage between the sensor terminals at the moment when the sensing structure is electrically connected to the second reference structure via the switching device, and the value of the voltage is usually unknown. However, since the voltage sensor necessarily has a finite internal resistance, charge balancing occurs between the sensing structure and the second reference structure in the case of a continuous electrical connection. This results in the voltage between the sensor terminals dropping to a pre-given value after a characteristic time. Briefly speaking, the voltage between the sensor terminals drops to zero or substantially to zero within a certain time.

[0012] However, when moisture couples the sensing structure to the first reference structure, the situation is described differently. In this case, the sensing structure obtains a more or less defined potential position from the first reference structure. In other words, when charge flows from the sensing structure via the voltage sensor to the second reference structure, the first reference structure recharges the sensing structure, or vice versa. This results in the voltage between the sensor terminals either rising again if it has already dropped accordingly, or not dropping to the value expected for the dry state at all, or dropping more slowly than expected for the dry state. Correspondingly, the evaluation unit can determine whether there is moisture between the first reference structure and the sensing structure by evaluating the sensor signal, in particular by evaluating the time curve of the sensor signal and by comparing it with a pre-determined target behavior in the dry state of the electronic switching circuit.

[0013] For this purpose, a dedicated voltage supply for the sensing structure is advantageously not required. Furthermore, it is not necessary to accurately know the intrinsic resistance of the sensing structure. Similarly, it is not necessary to generate a current through the sensing structure and measure the change in this current in order to detect moisture. Thus, compared to applying a dedicated voltage and the corresponding current measurement, fewer components are required, namely in particular only one voltage sensor instead of a current sensor and a voltage source. Nor do the corresponding additional electrical connections occur. This can also have advantages in terms of the structural space or the area requirement on the circuit carrier of the electronic switching circuit.

[0014] The moisture that couples the first reference structure to the detection structure can be, for example, water that enters from the outside. However, it can also involve a liquid that is provided within the electronic switch circuit or within the electronic device or battery pack, and the electronic switch circuit can be used in or with the electronic device or battery pack. For example, the electronic switch circuit can be part of a battery pack having a plurality of battery cells. In this case, the moisture can, for example, correspond to the liquid electrolyte that overflows from a damaged battery cell.

[0015] If it is determined, by means of the evaluation of the sensor signal by the evaluation unit, that moisture is present, the evaluation unit can, for example, take corresponding measures, in particular risk-reducing measures, such as deactivating the electronic switch circuit, interrupting the corresponding through-current, and / or generating a warning signal, etc. For this purpose, the evaluation unit can also control other components of the electronic switch circuit or, if necessary, of the electronic device or the battery pack, if necessary.

[0016] The electronic switch circuit or the moisture detection device can, for example, have an analog-to-digital converter ADC that includes a voltage sensor or is a voltage sensor. Thus, the sensor terminal can correspond to the input of the ADC.

[0017] According to at least one embodiment of the electronic switch circuit, when the second sensor terminal is separated from the second reference structure by the switching device, the detection structure is electrically separated from the first reference structure and from the second reference structure in the dry state of the electronic switch circuit.

[0018] The dry state of the electronic switch circuit corresponds in particular to a state in which neither the first reference structure nor the second reference structure is coupled to the detection structure by moisture. The dry state of the electronic switch circuit can also be understood, for example, as the rated state.

[0019] Thereby, the potential position of the detection structure in the dry state is independent of the first reference potential at the first reference potential terminal and the second reference potential at the second reference potential terminal. The elimination of this independence by moisture results, as described, in the detectability of moisture.

[0020] According to at least one embodiment, the evaluation unit is designed to detect the sensor signal during the connection of the second sensor terminal to the second reference structure in order to detect moisture.

[0021] The evaluation of the sensor signal can be different in different design variants of the electronic switching circuit. For example, the switching device can electrically connect the second reference structure to the second sensor terminal substantially permanently, such that after a certain decay time the voltage between the sensor terminals is equal to zero. The evaluation unit can then monitor the sensor signal in such a way that it checks whether the rise of the sensor signal or the voltage between the sensor terminals exceeds a predefined limit value. If this is the case, the presence of moisture can be inferred.

[0022] In other embodiments, the evaluation unit can periodically establish and cancel the electrical connection between the second sensor terminal and the second reference structure, such that in the dry state a drop in the corresponding voltage can be observed each time the second sensor terminal and the second reference structure are reconnected. Now, the evaluation unit can compare the course of the voltage with a nominal course in order to determine, for example: whether the voltage drops more slowly than expected in the dry state and / or whether the voltage drops to at least a predefined corresponding limit value after a predefined time, in order to detect moisture.

[0023] According to at least one embodiment, the evaluation unit is designed to detect the time course of the sensor signal during the connection of the second sensor terminal to the second reference structure, in particular by means of the switching device, and to detect moisture based on this time course.

[0024] According to at least one embodiment, the switching device is designed to connect the second reference structure to the second sensor terminal at a first starting time, wherein the second reference structure is not connected to the second sensor terminal directly before the first starting time, in particular.

[0025] According to at least one embodiment, the evaluation unit is designed to compare the sensor signal with a predefined limit value at a first measurement time, wherein a predefined first time interval lies between the first starting time and the first measurement time. The evaluation unit is designed to detect moisture based on the result of the comparison.

[0026] For this purpose, the switching device in particular has a switching element which is arranged between the second reference structure and the second sensor terminal and can be opened in order to separate the second reference structure from the second sensor terminal, and which can be closed in order to connect the second reference structure to the second sensor terminal. The switching device also has a control unit which can control the switching element accordingly. Here, the evaluation unit can comprise the control unit or vice versa, or the two units can be constructed independently of one another.

[0027] If the evaluation unit determines, based on the evaluation of the sensor signal, in particular based on a comparison with a limit value, that the voltage between the first and second sensor terminals has not dropped to at least the limit value at the first measurement time, it can be inferred that moisture is present. Alternatively, the evaluation unit can also determine whether the voltage first drops below the limit value and has exceeded this limit value again at the first measurement time. This can also indicate the presence of moisture.

[0028] According to at least one embodiment, the evaluation unit is designed to compare the time profile of the sensor signal after a first start time with a pre-given nominal profile and to detect moisture based on the result of this comparison.

[0029] According to at least one embodiment, the moisture detection device includes another conductive detection structure, which is arranged in the surroundings of the second reference structure of the electronic switch circuit. The moisture detection device has another voltage sensor, which has another first sensor terminal, and the another first sensor terminal is connected to the another detection structure. The another second sensor terminal of the another voltage sensor can be connected to the first reference structure. The another voltage sensor is designed to generate another sensor signal based on the voltage between the another first sensor terminal and the another second sensor terminal. The switching device is designed to optionally separate the another second sensor terminal from the first reference structure and connect it to the first reference structure. The evaluation unit is designed to detect moisture based on the another sensor signal generated during the connection of the another second sensor terminal to the first reference structure, and this moisture electrically couples the second reference structure to the another detection structure.

[0030] Here, the evaluation unit can thus evaluate the sensor signal and the second sensor signal. Optionally, the evaluation unit can have two mutually independent evaluation subunits for this purpose, and the evaluation subunits can also be spatially separated from each other if necessary. The first of the evaluation subunits can obtain the sensor signal, and the second of the evaluation subunits can obtain the another control signal.

[0031] The switching device can, for example, have another switching element, which is arranged between the first reference structure and the another second sensor terminal to establish or disconnect the connection between the first reference structure and the another second sensor terminal.

[0032] The embodiments regarding the detection structure and the voltage sensor can be similarly transferred to the embodiments with the another detection structure and the another voltage sensor, where the roles of the first reference structure and the second reference structure are interchanged accordingly.

[0033] According to at least one embodiment, in particular an embodiment in which the moisture detection device does not have the other detection structure and the other voltage sensor, the switching device is designed to selectively separate the second sensor terminal from the first reference structure and connect it to the first reference structure, for example by means of a correspondingly provided other switching element of the switching device.

[0034] The switching device is in particular designed to connect the second sensor terminal to the first reference structure or to the second reference structure.

[0035] Thereby, the above-described embodiment for detecting moisture (which electrically couples the first reference structure to the detection structure) can be transferred to the detection of moisture that electrically couples the second reference structure to the detection structure. Thus, a single detection structure can be advantageously used for detecting both cases.

[0036] According to at least one embodiment, the switching device is designed to separate the second sensor terminal from the first reference structure and connect the second sensor terminal to the second reference structure during a first measurement period.

[0037] According to at least one embodiment, the switching device is designed to separate the second sensor terminal from the second reference structure and connect the second sensor terminal to the first reference structure during a second measurement period after the first measurement period, for example directly after the first measurement period.

[0038] In other words, the second sensor terminal is connected to the second reference structure and separated from the first reference structure during the first measurement period and / or the second sensor terminal is separated from the second reference structure and connected to the first reference structure during the second measurement period.

[0039] Thus, the evaluation unit can detect moisture by evaluating the sensor signal during the first measurement period, which moisture couples the first reference structure to the detection structure, and detect moisture during the second measurement period, which moisture couples the second reference structure to the detection structure. Other similar first and second measurement periods can follow each other alternately, such that both cases can be detected alternately.

[0040] The first measurement period, for example, lasts from a first start time until a first end time, wherein a first measurement time is between the first start time and the first end time. Correspondingly, the second measurement period can last from a second start time until a second end time, wherein a second measurement time is between the second start time and the second end time, wherein in particular a predetermined second time interval exists between the second start time and the second measurement time.

[0041] For example, the evaluation unit can compare the sensor signal at the second measurement moment with another predefined limit value, and detect moisture according to the result of this comparison, which couples the second reference structure to the detection structure.

[0042] Other possibilities for detecting moisture that couples the first reference structure to the detection structure can also be correspondingly applied to detecting moisture that couples the second reference structure to the detection structure.

[0043] According to at least one embodiment, the evaluation unit is designed to detect the sensor signal during the connection of the second sensor terminal to the first reference structure, especially during the second measurement cycle, in order to detect moisture that electrically couples the second reference structure to the detection structure. In particular, the evaluation unit can be designed to detect the time curve of the sensor signal during the connection of the second sensor terminal to the second reference structure and detect the corresponding moisture according to the time curve.

[0044] According to at least one embodiment, the evaluation unit is designed to take risk reduction measures when moisture that electrically couples the first reference structure to the detection structure is detected.

[0045] According to at least one embodiment, the evaluation unit is designed to take risk reduction measures when moisture that electrically couples the second reference structure to the detection structure or the other detection structure is detected.

[0046] Taking risk reduction measures can, for example, include generating or causing a warning signal and / or generating or causing a control signal for another switching element in order to interrupt the current through the electronic switching circuit, etc. Taking risk reduction measures can also include deactivating the electronic switching circuit, the electronic device, and / or the battery pack connected to or including the electronic switching circuit.

[0047] According to at least one embodiment, the evaluation unit is designed to introduce an interruption in the electrical connection between the first reference potential terminal and the first reference structure and / or an interruption in the electrical connection between the second reference potential terminal and the second reference structure in order to take risk reduction measures.

[0048] For this purpose, the electronic switching circuit, the moisture detection device, or the switching device can correspondingly have a switching element that can be controlled by the evaluation unit.

[0049] According to another aspect of the present invention, there is provided a battery pack for supplying electrical energy to an electronic device. The battery pack has at least one battery cell, in particular a lithium-ion battery cell. The at least one battery cell has a first electrode and a second electrode. The battery pack has an electronic switching circuit according to the present invention. Here, the first reference potential terminal of the electronic switching circuit is directly or indirectly connected to the first electrode, and the second reference potential terminal is directly or indirectly connected to the second electrode of the battery pack.

[0050] According to at least one embodiment of the battery pack, the electronic switching circuit includes a battery management system for the battery pack.

[0051] According to at least one embodiment, the electronic switching circuit includes at least one switching element for interrupting the discharge current from the at least one battery cell to the electronic device and / or at least one switching element for interrupting the charging current from the charging device to the at least one battery cell.

[0052] The risk reduction measures can for example include interrupting the discharge current and / or the charging current.

[0053] According to another aspect of the present invention, there is provided an electronic device having an electronic switching circuit according to the present invention and / or having a battery pack according to the present invention.

[0054] The electronic device can for example be designed as a power tool or a household appliance. The electronic device can also be designed as an electrically drivable vehicle, in particular a small vehicle, for example designed as an electrically drivable bicycle or an electrically drivable motorcycle, etc.

[0055] According to another aspect of the present invention, there is provided a method for detecting moisture in an electronic switching circuit. Here, in particular, the second sensor terminal of a voltage sensor, in particular of the electronic switching circuit, is connected to a conductive second reference structure of the electronic switching circuit by means of a switching device of the electronic switching circuit, wherein the second reference structure is connected to the second reference potential terminal of the electronic switching circuit. By means of the voltage sensor, a sensor signal is generated according to the voltage between the first sensor terminal and the second sensor terminal of the voltage sensor. Here, the first sensor terminal is connected to a conductive detection structure of the electronic switching circuit and the detection structure is arranged in the surroundings of the conductive first reference structure of the electronic switching circuit. According to the sensor signal, moisture is detected, in particular by means of an evaluation unit of the electronic switching circuit, which moisture electrically couples the first reference structure and the detection structure.

[0056] Other embodiments of the method according to the invention result directly from different design variants of the electronic switching circuit according to the invention, the battery pack according to the invention and the electronic device according to the invention, and vice versa accordingly. The electronic switching circuit according to the invention can in particular be designed to carry out the method according to the invention or to execute such a method. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention will now be explained in detail with the aid of specific exemplary embodiments and the associated schematic drawings. In the drawings, identical or functionally identical elements may be provided with the same reference signs. The description of identical or functionally identical elements need not necessarily be repeated with respect to the different drawings.

[0058] In the drawings:

[0059] Figure 1 A schematic diagram showing an exemplary embodiment of the electronic switching circuit according to the invention;

[0060] Figure 2 A schematic diagram showing a voltage profile;

[0061] Figure 3 A schematic diagram showing another exemplary embodiment of the electronic switching circuit according to the invention;

[0062] Figure 4 A schematic diagram showing other voltage profiles;

[0063] Figure 5 A schematic diagram showing another exemplary embodiment of the electronic switching circuit according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0064] In Figure 1 the electronic switching circuit 1 according to the invention is schematically shown. The switching circuit 1 has a first reference potential terminal 9a and a second reference potential terminal 9b, which can be connected, for example, to the respective electrodes of a voltage source. For example, the electronic switching circuit 1 can be part of a battery pack having a plurality of battery cells. The battery cells can be connected in series and / or in parallel, for example, and have a common first electrode and a common second electrode for outputting a voltage. In this case, the first electrode can be connected to the first reference potential terminal 9a and the second electrode can be connected to the second reference potential terminal 9b. However, the electronic switching circuit 1 can also be used in other cases, in which the reference potential terminals 9a, 9b are at different potentials.

[0065] The switching circuit 1 has a first conductive reference structure 4a and a second conductive reference structure 4b. The first reference structure 4a is connected to a first reference potential terminal 9a, and the second reference structure 4b is connected to a second reference potential terminal 9b. The reference structures 4a, 4b can correspond, for example, to the conductor circuits or wirings of the switching circuit 1. Here, the switching circuit 1 can have a plurality of other electronic components, which are not shown in Figure 1 for the sake of clarity. The electronic switching circuit 1 also has a moisture detection device 2. In this case, the function of the moisture detection device 2 is independent of the specific design of the remaining components of the switching circuit 1, so that only the reference structures 4a, 4b and the reference potential terminals 9a, 9b will be referred to hereinafter.

[0066] The moisture detection device 2 includes a conductive detection structure 3, which can also be configured, for example, as a wire or a conductor circuit and is arranged in the vicinity of the first reference structure 4a. In addition, the moisture detection device 2 has a voltage sensor 5, which has a first sensor terminal 6a and a second sensor terminal 6b. The first sensor terminal is connected to the detection structure 3, and the second sensor terminal can be connected to or separated from the second reference structure 4b through a switching element 8. For this purpose, the moisture detection device 2 has a control unit 10, which can correspondingly control the switching element 8 to establish or cancel the connection. The switching element 8 can include a transistor, for example, a field effect transistor.

[0067] In addition, the moisture detection device 2 has an evaluation unit 7, which is connected to the voltage sensor 5 or can include the voltage sensor 5 in some embodiments. The evaluation unit 7 and the control unit 10 can also be configured as a common control and evaluation unit in different embodiments.

[0068] The voltage sensor 5 can generate a sensor signal that reproduces the voltage between the two sensor terminals 6a, 6b. Therefore, if the switching element 8 is closed so that the second reference structure 4b is connected to the second sensor terminal 6b, the sensor signal thus reproduces the voltage U between the detection structure 3 and the second reference structure 4b. The corresponding variation curve of the voltage U is schematically shown in Figure 2 as a function of time t.

[0069] In Figure 2In the example, the switching element 8 is first disconnected and then closed by the control unit 10 at the starting time t0. In the dry state of the electronic switching circuit 1, as long as the switching element 8 is disconnected, the detection structure 3 is electrically separated from the first reference structure 4a and the second reference structure 4b. Therefore, the potential of the detection structure 3 is usually uncertain, that is, floating. Correspondingly, a voltage drop between the detection structure 3 and the second reference structure 4b occurs at time t0. However, due to the finite internal resistance of the voltage sensor 5, this voltage decreases over time and approximately reaches zero at a later time t1 in the dry state of the electronic switching circuit 1.

[0070] However, if moisture 11 is present in the electronic switching circuit 1, the moisture electrically connects the first reference structure 4a to the detection structure 3 as shown in Figure 1 , then at least partial charge balancing can occur between the detection structure 3 and the first reference structure 4a. Since the reference structures 4a, 4b are at different potentials, this causes a voltage greater than zero between the sensor terminals 6a, 6b. Correspondingly, the voltage U can rise again after time t1, as shown in Figure 2 . If, when moisture 11 is already present, the connection between the second sensor terminal 6b and the second reference structure 4b is established by closing the switching element 8, the voltage U does not necessarily drop to zero as shown in Figure 2 , but remains at a higher value. The corresponding course or value of the voltage U can be compared with the desired rated course or rated value of the voltage by means of the evaluation unit 7 in order to detect the moisture 11.

[0071] In Figure 3 , another exemplary embodiment of the electronic switching circuit 1 according to the invention is schematically shown, which is based on the embodiment of Figure 1 .

[0072] In Figure 3 's embodiment, the evaluation unit 7 and the control unit 10 are not shown for the sake of clarity. The switching element 8 can be configured or act as a commutating switch, for example. The control unit 10 can then control the switching element 8 such that the second sensor terminal 6b is connected to the first reference structure 4a and separated from the second reference structure or vice versa. Alternatively, the moisture detection device 2 can have the switching element 8 as described with respect to Figure 1 and another switching element (not shown), which can also be controlled by the control unit 10 and is arranged between the first reference structure 4a and the detection structure 3. Correspondingly, the control unit 10 can control the switching element 8 and the other switching element such that the switching element 8 is closed and the other switching element is open or vice versa.

[0073] Thus, the control unit 10 can selectively connect the detection structure 3 to the first reference structure 4a and the second reference structure 4b. If the detection structure 3 is connected to the second reference structure 4b and separated from the first reference structure 4a, the evaluation unit 7 can detect the moisture 11 between the first reference structure 4a and the detection structure 3 as described with respect to Figure 1 Conversely, if the detection structure 3 is connected to the first reference structure 4a and separated from the second reference structure 4b, the evaluation unit 7 can detect the moisture 11 that electrically connects the second reference structure 4b to the detection structure 3. The embodiments with respect to Figure 1 and Figure 2 apply analogously here.

[0074] In each embodiment, the control unit 10 can periodically control the switching element 8 and the other switching element such that, during successive measurement cycles, the first reference structure 4a or the second reference structure 4b is alternately connected to the detection structure 3 in order to alternately perform the corresponding moisture detection. The corresponding voltage changes between the two sensor terminals 6a, 6b are schematically shown in Figure 4 Here, the voltage change curve U as a function of time t corresponds to the voltage change curve between the second reference structure 4b and the detection structure 3, and the voltage change curve U as a function of time t at least corresponds to the voltage change curve between the first reference structure 4a and the detection structure 3. As implemented with respect to Figure 2 the second reference structure 4b is connected to the detection structure 3 at time t0 such that the voltage U drops from a finite value to an approximately zero value until time t1. At time t1, the second reference structure 4b is, for example, separated from the detection structure 3 and the detection structure 3 is connected to the first reference structure 4a. Correspondingly, the voltage U' has a finite value that drops to a value close to zero, for example, over the course of time until another time t2. At time t2, the detection structure 3 is again separated from the first reference structure 4a and connected to the second reference structure 4b such that the voltage change curve of the voltage U repeats as described between t2 and the subsequent time t3. It should be noted that the approximate change curves of the voltages U, U' correspond to the dry state of the switching circuit 1. Due to the corresponding deviations as described with respect to Figure 2 the evaluation unit 7 can thus infer the moisture 11 between the detection structure 3 and one of the reference structures 4a, 4b.

[0075] In Figure 3 an optional resistor 14 is shown that is connected in series with the internal resistance of the voltage sensor 5. Thereby, the resistance between the sensor terminals 6a, 6b can be further increased in order to thereby delay the aforementioned voltage drop. In this way, the voltage change curve can be matched to specific requirements. Such a resistor 14 can also be provided in accordance with Figure 1is provided in the embodiment of

[0076] In addition, in Figure 3 , the optional inductance element 12a and the optional resistor 13a are connected in series between the first reference structure 4a and the detection structure 3. By correspondingly selecting the inductance of the inductance element 12a and the ohmic resistance of the resistor 13a, the coupling can be adjusted accordingly so as to adjust the change of the voltage over time during the measurement interval for detecting moisture 11. This can also be optionally provided in the embodiment according to Figure 1 . In addition, as Figure 3 shows, another inductance element 12b can be connected in series with another resistor 13b between the detection structure 3 and the second reference structure 4b. These inductance elements have functions similar to the functions implemented for the inductance element 12a and the resistor 13a.

[0077] In Figure 5 shows another exemplary embodiment of the electronic switching circuit 1 according to the present invention, which is based on Figure 1 . For the sake of clarity, the sensor terminals 6a, 6b, as well as the control unit 10 and the evaluation unit 7 are not shown in the same way as the switching element 8.

[0078] In Figure 5 , the moisture detection device 2 has another detection structure 3', and the another detection structure is arranged in the surrounding environment of the second reference structure 4b. The moisture detection device 2 further includes another voltage sensor, and the another voltage sensor has another first sensor terminal and a second sensor terminal. The first sensor terminal is connected to the another detection structure 3', and the second sensor terminal is switchably connected to the first reference structure 4a. For this purpose, the moisture detection device 2 has another switching element (not shown), and the another switching element can be controlled by the control unit 10 to connect or disconnect the first reference structure 4a from the another second sensor terminal. The functional mode of the detection structure 3' or the voltage sensor is similar to the functional mode of the detection structure 3 and the voltage sensor 5, as described with respect to Figure 1 .

[0079] Therefore, according to Figure 5 , the moisture 11 that couples the detection structure 3 to the first reference structure 4a can be detected by evaluating the sensor signal of the voltage sensor 5 as described. The moisture 11 that couples the another detection structure 3' to the second reference structure 4b can be detected by the evaluation unit 7 in a similar manner by evaluating the another sensor signal of the another voltage sensor 5.

[0080] The battery pack has the electronic switching circuit 1 according to the present invention, as for example with respect to Figures 1 to 5As described, it has at least one battery cell, wherein a first electrode of the battery cell is connected to a first reference potential interface and a second electrode of the battery cell is connected to a second reference potential interface.

[0081] Furthermore, the battery pack may have two or more external contacts for connecting the battery pack to an electronic device. Here, a first external contact among the external contacts is connected to a first reference potential terminal 9a, and a second external contact among the external contacts is connected to a second reference potential terminal 9b. The external contacts are potential sites for moisture to enter the battery pack and thus into the switching circuit 1.

[0082] Regarding the possible arrangement of the detection structure 3 of the switching circuit 1 with respect to the external contacts, a part of the detection structure 3 can be arranged between adjacent external contacts among the external contacts so as to be able to detect moisture accordingly.

[0083] Another exemplary embodiment of the battery pack according to the present invention. The battery pack may include a circuit board that, for example, carries a battery management system for the battery pack. Furthermore, the circuit board can partially support the electronic switching circuit 1 or the moisture detection device 2. The detection structure 3 can, for example, have one or more wire loops that are guided through the area of the battery pack where the battery cells are arranged. The detection structure 3 can, for example, extend in a meandering manner between the individual battery cells. In this way, moisture that enters the area of the battery cells can be detected, and this has particular safety importance.

[0084] A battery cell of the battery pack according to the present invention, which battery cell has a housing that forms the negative electrode of the battery cell and is, for example, connected to the first reference potential terminal 9a. Furthermore, the battery has a current interruption element, which is also called CID (English: “Current Interruption Device”) and is electrically insulated from the housing by means of an insulating element of the battery cell. The current interruption element can correspond to the positive electrode of the battery cell and is, for example, connected to the second reference potential terminal 9b.

[0085] Another exemplary arrangement of the detection structure 3, which can also be configured as a wire loop structure here. The detection structure 3 is, for example, guided to extend in the vicinity between the current interruption element and the housing, for example, between the housing and the current interruption element. Thus, moisture can be detected at a particularly critical site of the battery pack.

[0086] For example, the detection structure 3 can be embedded in another insulating element, which insulating element is, for example, porous or sponge-like in construction, such that moisture can penetrate into the detection structure 3 through the electrical insulating element, but the detection structure 3 remains electrically insulated from the housing and the current interruption element.

[0087] List of reference numerals:

[0088] 1 Switching circuit

[0089] 2 Moisture detection device

[0090] 3, 3’ Detection structure

[0091] 4a, 4b Reference structure

[0092] 5 Voltage sensor

[0093] 6a, 6b Sensor terminals

[0094] 7 Evaluation unit

[0095] 8 Switching element

[0096] 9a, 9b Reference potential terminals

[0097] 10 Controller

[0098] 11 Moisture

[0099] 12a, 12b Sensing elements

[0100] 13a, 13b, 14 Resistors

Claims

1. An electronic switch circuit (1) having a moisture detection device (2), the moisture detection device (2) having: — a conductive detection structure (3), which is arranged in the surrounding environment of a conductive first reference structure (4a) of the electronic switch circuit (1), wherein, The first reference structure (4a) is connected to the first reference potential terminal (9a) of the electronic switch circuit (1), - A voltage sensor (5) having a first sensor terminal (6a) connected to the detection structure (3) and a second sensor terminal (6b) that can be connected to a conductive second reference structure (4b) of the electronic switch circuit (1), the second reference structure being connected to the second reference potential terminal (9b) of the switch circuit (1), wherein the voltage sensor (5) is designed to generate a sensor signal based on the voltage between the first sensor terminal (6a) and the second sensor terminal (6b); - A switching element (8) designed to selectively disconnect or connect the second sensor terminal (6b) from the second reference structure (4b), and - An evaluation unit (7) designed to detect moisture (11) based on the sensor signal, the moisture electrically coupling the first reference structure (4a) to the detection structure (3); Wherein, - The moisture detection device (2) includes another conductive detection structure (3'), the other detection structure being disposed in the surroundings of the second reference structure (4b) of the electronic switch circuit (1); - The moisture detection device (2) has another voltage sensor having another first sensor terminal connected to the other detection structure (3') and another second sensor terminal that can be connected to the first reference structure (4a), wherein the other voltage sensor is designed to generate a sensor signal based on the voltage between the other first sensor terminal and the other second sensor terminal; - Another switching element that selectively disconnects or connects the other second sensor terminal from the first reference structure (4a), Wherein the control unit periodically controls the switching element (8) and the other switching element such that during consecutive measurement cycles, the first reference structure or the second reference structure is alternately connected to the detection structure in order to alternately perform corresponding moisture detection; and - The evaluation unit (7) is also designed to detect moisture (11) based on the other sensor signal, the moisture electrically coupling the second reference structure (4b) to the other detection structure (3').

2. The electronic switch circuit (1) having a moisture detection device (2) according to claim 1, wherein, The evaluation unit (7) is designed to detect the sensor signal during the connection of the second sensor terminal (6b) to the second reference structure (4b) in order to detect moisture (11).

3. The electronic switch circuit (1) having a moisture detection device (2) according to claim 1 or 2, wherein, The evaluation unit (7) is designed to detect the time profile of the sensor signal during the connection of the second sensor terminal (6b) to the second reference structure (4b) and to detect the corresponding moisture (11) based on the time profile.

4. The electronic switch circuit (1) having a moisture detection device (2) according to claim 1 or 2, wherein, — The switching element (8) is designed to connect the second reference structure (4b) to the second sensor terminal (6b) at a first starting time; — The evaluation unit (7) is designed to compare the sensor signal with a predefined limit value at a first measurement time, wherein a predefined first time interval is located between the first starting time and the first measurement time; and — The evaluation unit (7) is designed to detect moisture (11) based on the result of the comparison.

5. The electronic switch circuit (1) with a moisture detection device (2) according to claim 1 or 2, wherein, The evaluation unit (7) is designed to take risk-reducing measures when moisture (11) that electrically couples the first reference structure (4a) to the detection structure (3) is detected.

6. The electronic switch circuit (1) with a moisture detection device (2) according to claim 5, wherein, The evaluation unit (7) is designed to introduce an interruption of the electrical connection between the first reference potential terminal (9a) and the first reference structure (4a) and / or an interruption of the electrical connection between the second reference potential terminal (9b) and the second reference structure (4b) in order to take risk-reducing measures.

7. A battery pack for supplying electrical energy to an electronic device, the battery pack (15) having: — At least one battery cell with a first electrode and a second electrode; — An electronic switch circuit (1) having a moisture detection device (2) according to any one of the preceding claims, wherein, The first reference potential terminal (9a) is connected to the first electrode and the second reference potential terminal (9b) is connected to the second electrode.

8. An electronic device having an electronic switch circuit (1) with a moisture detection device (2) according to any one of claims 1 to 6 or having a battery pack according to claim 7.

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