ELECTRICAL DEVICE AND METHOD FOR OPERATING AN ELECTRICAL DEVICE

Description

State of the art

[0001] The invention relates to an electrical device and a method for operating an electrical device.

[0002] An electrical device is protected against dirt or moisture by structural measures.

[0003] An electrical device according to the preamble of claim 1 is already known from US 2016 / 313270 A1.

[0004] DE 10 2016 207 566 A1 describes a battery pack that can discharge itself under certain conditions.

[0005] US 2018 / 198294 A1 discloses a battery pack for tools.

[0006] DE 10 2008 043473 A1 discloses a fuel cell with a humidity sensor device.

[0007] It is difficult to maintain such protection against dirt or moisture over the lifetime of the product. For example, mechanical influences can damage the protection provided by design measures. Furthermore, dirt or moisture can also develop inside the electrical device, for example, in the event of a defect in an electrolytic capacitor or a battery cell in the battery pack that contains electrolyte. Disclosure of the invention

[0008] By means of an electrical device and a method for operating the electrical device according to the independent claims, operational reliability of the electrical device with regard to dirt or moisture is improved.

[0009] The electrical device has a housing with a first external contact and a second external contact for supplying power to the electrical device, wherein the electrical device comprises a first conductor, a second conductor and an evaluation device in the housing, wherein the first conductor is electrically connected to a first contact for a first potential, wherein the second conductor is electrically connected to a second contact for a second potential different from the first potential, wherein the first conductor and the second conductor are electrically connected to the evaluation device, wherein the first conductor and the second conductor are arranged such that an electrical connection between the first conductor and the second conductor due to dirt or moisture in the housing can be detected by means of the evaluation device. In this respect, conductive dirt or moisture can be detected regardless of whether damage has occurred or not.The second conductor is electrically connected via a resistor to an input of the evaluation device for detecting dirt or moisture. This resistor represents a protective resistor for the evaluation device. The evaluation device is designed to detect a fault if an electrical connection between the first conductor and the second conductor is detected due to dirt or moisture, and the evaluation device is designed to deactivate the electrical device in the event of a fault. This further increases operational reliability. The first conductor and the second conductor are two adjacent conductor tracks that are not insulated from the surroundings of the circuit board.

[0010] Preferably, the second conductor is electrically connected to the second contact and an input of the evaluation device for a supply voltage via a resistor. This resistor can be a pull-up resistor, to which the supply voltage of the evaluation device is applied during operation of the electrical device. In this case, the supply voltage represents the second potential. This allows dirt or moisture to be detected cost-effectively.

[0011] Preferably, the first conductor is electrically connected to an input of the evaluation device for a reference potential. In this case, the reference potential represents the first potential. This allows a potential difference for detecting dirt or moisture to be realized cost-effectively.

[0012] Preferably, the first conductor and the second conductor are electrically insulated from each other and arranged adjacent to each other in a region at least in sections and without insulation. This allows for the detection of dirt or moisture in predetermined sections.

[0013] Preferably, the electrical device comprises a rechargeable battery cell and a discharge device, wherein the evaluation device is configured to discharge the rechargeable battery cell with the discharge device in the event of a fault. This further increases the operational reliability of an electrical device powered by a rechargeable battery cell.

[0014] Preferably, the electrical device comprises a charging device for a rechargeable battery cell, wherein the evaluation device is configured to deactivate the charging device in the event of a fault, or wherein the evaluation device is configured to prevent charging of a rechargeable battery cell by a charging device in the event of a fault. This further increases the operational reliability of a charging device.

[0015] Preferably, different pairs of first conductor and second conductor are arranged in the electrical device, electrically insulated from one another, and electrically connected to different inputs of the evaluation device. The evaluation device is configured to determine a number of pairs for which the electrical connection is detected. The evaluation device is configured to determine a fault in the electrical device depending on the number. This enables detection of a degree of impairment of the operational reliability of the electrical device due to dirt or moisture.

[0016] Preferably, a first conductor and a plurality of second conductors are arranged adjacent to one another and electrically insulated from one another in the electrical device. The evaluation device is configured to determine a number of second conductors for which the electrical connection of the first conductor to the second conductor is detected. The evaluation device is configured to determine a fault in the electrical device depending on the number. This enables detection of a size or type of contamination or an amount of moisture present in the electrical device.

[0017] The method for operating the electrical device in which at least one first conductor, at least one second conductor and an evaluation device are arranged, wherein the at least one first conductor is electrically connected to a contact for a first potential, wherein the at least one second conductor is electrically connected to a contact for a second potential different from the first potential, wherein the electrical device is supplied with energy by means of the contacts, wherein the at least one first conductor and the second conductor are electrically connected to the evaluation device, wherein the at least one first conductor and the at least one second conductor are arranged such that an electrical connection of at least one first conductor and at least one second conductor can be detected by means of dirt or moisture by means of the evaluation device,that if an electrical connection between at least one first conductor and at least one second conductor is detected by the evaluation device due to dirt or moisture, a fault is recognized, and in the event of a fault, the electrical device is deactivated, a battery cell is discharged using a discharge device, or a charging device is deactivated, or charging using a charging device is prevented. This improves the operational reliability of the electrical device over its service life.

[0018] Further advantageous embodiments will become apparent from the following description and the drawing. The drawing shows: Fig. 1 is a schematic representation of an electrical device in a first embodiment, Fig. 2 is a schematic representation of a first circuit, Fig. 3 is a schematic representation of an electrical device in a second embodiment, Fig. 4 is a schematic representation of an electrical device in a third embodiment, Fig. 5 is a schematic representation of a second circuit, Fig. 6 is steps in a method for operating the electrical device.

[0019] In the following, aspects of an electrical device are described using the example of a battery charging system, which can also be used for other electrical devices.

[0020] Rechargeable batteries can be used to operate electrical devices without dependence on a power distribution grid. To use a higher voltage than that of a single battery cell, it is common practice to combine multiple battery cells into a battery pack. Some electrical devices can be operated with replaceable battery packs. This allows the user to simply swap out a fully charged battery pack when it runs out and continue working without interruption.

[0021] To ensure that each cell in a battery pack consisting of multiple cells operates within its specifications, battery packs can have dedicated electronic components that monitor the cells' voltage and temperature and enable or disable charging and discharging depending on the operating state. Dedicated integrated circuits or microcontrollers are used for this purpose. The electronic components can be mounted on circuit boards.

[0022] When using battery packs, especially in power tools, but also gardening equipment or small automotive devices such as e-bikes, the devices, battery packs, and chargers can be exposed to a dirty environment. The ingress of dirt and / or moisture into such an electrical device can lead to unwanted electrical connections that impair the functionality of the device, battery pack, or a charger used to charge the battery pack. In unfavorable cases, such contamination and / or moisture could also limit safe operation. This is particularly the case if the amount of dirt and / or moisture that has penetrated is greater than expected.

[0023] Therefore, electrical devices can be designed to provide special protection against the ingress of water and dirt. Protection against moisture and dirt can be achieved, for example, by encapsulating electronic components.

[0024] Figure 1 shows a schematic representation of the electrical device in a first embodiment.

[0025] In the first embodiment, the electrical device comprises a circuit board 1 with contacts 2, which supports at least one electronic component 3, e.g., for battery management. In the example, a first contact for a first potential and a second contact for a second potential, different from the first potential, are arranged on the circuit board 1. In the example, the first contact and the second contact are designed as contact springs or contact tulips.

[0026] At least one electronic component 3 is arranged on the circuit board 1. The electronic component 3 can be particularly protected against dirt or moisture. For example, the electronic component 3 is protected by encapsulation with a non-conductive, media-resistant plastic such as silicone. In the example, a first conductor 4 and a second conductor 5 are located on an area of ​​the circuit board 1 not protected by the encapsulation. In the example, the first conductor 4 and the second conductor 5 are two adjacent conductor tracks that are not insulated from the environment of the circuit board 1. The first conductor 4 and the second conductor 5 can each have a finger structure. These finger structures can be nested within one another. The nested finger structures thus cover a particularly large area on the circuit board 1. The conductor 4 and the conductor 5 can be evenly spaced from one another, at least in sections.

[0027] In this example, the first conductor 4 is electrically connected to one of the contact tulips. The electronic component 3 can be connected via a Figure 1 The electronic component 3 can be electrically connected to this contact tulip via a connection not shown. Figure 1 connection not shown must be electrically connected to the other of the contact tulips.

[0028] In the example, a first connection 6 to a first circuit for detecting dirt or moisture is provided for the second conductor 5. In the example, the first circuit is located in the electronic component 3.

[0029] In Figure 2 A schematic representation of the first circuit is shown. The first circuit comprises the first connection 6, a first resistor 7, a second resistor 8, and an evaluation device 9. The evaluation device 9 can comprise a microcontroller.

[0030] In this example, the first conductor 4 is electrically connected to an input of the evaluation device 9 for a reference potential of the electrical device. Figure 2 In the example shown, a negative reference potential is provided as the first potential. This can be applied to the first contact in the example.

[0031] In this example, the second conductor 5 is electrically connected via the first connection 6 and the first resistor 7 to an input of the evaluation device 9 for a supply voltage of the electrical device. Figure 2 In the example shown, a positive supply voltage is provided as the second potential. This can be applied to the second contact in the example.

[0032] In this example, the second conductor 5 is electrically connected via the first connection 6 and the second resistor 8 to an input of the evaluation device 9 for detecting dirt or moisture.

[0033] In the example, the input of the evaluation device 9 for detecting dirt or moisture and the input of the evaluation device 9 for a supply voltage of the electrical device are electrically connected via the first resistor 7 and the second resistor 8. The first resistor 7 is designed as a pull-up resistor. The second resistor 8 is designed as a protective resistor. The first resistor 7 and the second resistor 8 can be connected in series.

[0034] This enables the evaluation device 9 to very easily determine whether contamination is present. Normally, there is no connection between the first conductor 4 and the second conductor 5. The evaluation device 9 is designed to determine an applied potential at its input via the resistor 8. In the example, a high potential will be measured if there is no conductive connection between the first conductor 4 and the second conductor 5. Contamination represents a conductive connection between the first conductor 4 and the conductor 5. Since the first conductor 4 in the example is connected to the reference potential, the signal measured by the evaluation device 9 in the event of contamination will no longer be high, but low.

[0035] According to a Figure 3 schematically illustrated second embodiment, different areas of the circuit board 1 can be monitored separately. In Figure 3An example of two areas that can be monitored separately is shown.

[0036] In this example, the first conductor 4 is arranged as described for the first embodiment. The same first conductor 4 can be used for detection in both areas.

[0037] According to the second embodiment, two second conductors are provided. One of these conductors 5 is arranged adjacent to the first conductor 4 on one side of an interruption 10, as described for the first embodiment.

[0038] Another of these conductors 11 is arranged on another side of an interruption 10, as described for the first embodiment, adjacent to the first conductor 4. The conductor 11 is electrically connected to the evaluation device 9 via a connection 12. For this purpose, a circuit can be provided for connecting the conductor 11 via the connection 12 to another input of the evaluation device 9 for detecting dirt or moisture. This circuit can be designed as described for the connection 6 and the conductor 5. In this case, the evaluation device 9 comprises two inputs for detecting dirt or moisture.

[0039] The evaluation device 9 is thus able to very easily determine whether contamination is present on one side of the interruption 10, on another side of the interruption 10, or on both sides of the interruption 10. In this case, the evaluation device 9 can be designed to determine a potential present at both inputs, as described above.

[0040] Contamination can thus be reliably detected if conductive contamination has occurred. Possible measures following such detection include: Warning the user by means of a suitable indicator, blocking further use, restricting further use, saving the contamination event for possible warranty evaluation.

[0041] Depending on the intended use of the electrical device, a suitable measure can be selected.

[0042] If the electrical device includes a battery pack that is protected from dirt or moisture, further use can be blocked, e.g., by deactivation. If contamination is to be expected due to its intended use, e.g., because the battery pack is designed to be dirt-tolerant due to internal protective measures, a user warning can be provided.

[0043] According to the second embodiment, different pairs of first conductor 4 and second conductor 5 can be arranged in the electrical device in an electrically insulated manner from one another, which pairs are electrically connected to different inputs of the evaluation device 9.

[0044] In this case, the evaluation device 9 is configured to determine a number of pairs for which the electrical connection was detected. In this case, the evaluation device 9 can be configured to determine a fault condition of the electrical device depending on the number.

[0045] According to a third embodiment, a first conductor 4 and a plurality of second conductors can be arranged adjacent to one another and electrically insulated from one another in the electrical device. In this case, the evaluation device 9 is configured to determine a number of second conductors for which the electrical connection of the first conductor 4 to the second conductor is detected. In this case, the evaluation device 9 can be configured to determine a fault in the electrical device depending on the number.

[0046] With this circuit it is possible to monitor areas separately from one another or to count small amounts of contamination. For example, the evaluation device 9 can be designed to trigger a warning when a single particle is detected. For example, the evaluation device 9 can be designed to control an illuminated display, for example. For example, the evaluation device 9 can have a communication interface and be designed to send a message to a networked data terminal. The message can be sent when a particle is detected. The evaluation device 9 can be designed to block a battery pack from further use if, after a particle has been detected on a second conductor, a further particle is detected on a different second conductor.

[0047] It may be provided to arrange more than two pairs to enable the evaluation device 9 to count further particles using them

[0048] Monitored areas can be assigned to the pairs. This division into areas has the additional advantage of increasing clearance and creepage distances.

[0049] In Figure 4 is a schematic representation of an electrical device in the third embodiment for two second conductors, which are in Figure 4 are labeled 5 and 11.

[0050] Instead of or in addition to the detection of particles in different areas, the evaluation device 9 according to the third embodiment can be designed to detect contaminations of different sizes.

[0051] In one aspect of the third embodiment, different distances are provided between the first conductor 4 and the conductor 5, and between the first conductor 4 and the conductor 11. The distance between the conductor 5 and the conductor 11 may be substantially the same as the distance between the first conductor 4 and the conductor 5 or between the first conductor 4 and the conductor 11.

[0052] The remaining components of the third version are shown in the example according to the Figure 3 described second embodiment.

[0053] Figure 5 shows a schematic representation of a second circuit for the third embodiment.

[0054] In contrast to the first circuit, in this example, the first conductor 4 is electrically connected to the input of the evaluation device for the reference potential via a resistor 7b. Conductor 11 is electrically connected to the input of the evaluation device for the supply voltage via resistor 7. Conductor 5 is electrically connected to the input of the evaluation device 9 for detecting dirt or moisture via resistor 8.

[0055] In this case, the evaluation device 9 can be configured to determine a number of second conductors for which the electrical connection of the first conductor 4 to the second conductor is detected. In this case, the evaluation device 9 can be configured to determine a fault condition of the electrical device depending on the number.

[0056] Instead of or in addition to the number, the evaluation device 9 can be designed to determine a size or position of the contamination or moisture depending on an identification of the input of the evaluation device 9 at which the low potential was determined.

[0057] In the example, the first conductor 4 is connected to the reference potential. The evaluation device 9 is designed to detect an electrical connection between conductor 5 and first conductor 4 via conductor 5 due to conductive contamination. The evaluation device 9 is designed to detect conductive contamination between conductor 11 and first conductor 4 via conductor 5. In the example, the distance between conductor 11 and first conductor 4 is greater than the distance between conductor 5 and first conductor 4. The evaluation device 9 is designed to detect large-area contamination when there is a conductive connection between conductor 11 and first conductor 4. The evaluation device 9 is designed to detect, in contrast, small-area contamination when there is a conductive connection between conductor 5 and first conductor 4 but no conductive connection between conductor 11 and first conductor 4.

[0058] Figure 6schematically illustrates steps in a method for operating the electrical device.

[0059] In a step 602, it is checked whether an electrical connection of at least one first conductor 4 and at least one second conductor 5 is detected by the evaluation device 9 due to dirt or moisture.

[0060] If an electrical connection between at least one first conductor 4 and at least one second conductor 5 is detected by the evaluation device 9 due to dirt or moisture, step 604 is executed. Otherwise, step 602 is executed.

[0061] In step 604, an error is detected. For example, the error is detected depending on a detected particle size or number of particles, or depending on the number of affected areas of circuit board 1.

[0062] In the example, a measure is assigned to an error case. Possible measures include: Warning the user by means of a suitable indicator, blocking further use, restricting further use, saving the contamination event for possible warranty evaluation.

[0063] In the example, it may be intended to deactivate the electrical device, to discharge a battery cell using a discharge device, to deactivate a charging device or to prevent charging of a battery cell by a charging device in the event of a fault.

[0064] Depending on the intended use of the electrical device, a suitable measure is selected from an assignment in the example.

[0065] A step 606 is then executed.

[0066] In step 606 the selected action is executed.

[0067] For example, the user is warned by the appropriate indicator, further use of the electrical device is blocked or restricted, a contamination event is stored for possible warranty evaluation, or charging with a charging device is prevented. In this example, the electrical device may be deactivated, a battery cell discharged with a discharge device, or a charging device deactivated.

[0068] Subsequently, step 602 can be executed to continue monitoring or the method can be terminated.

Claims

1. Electrical device which has a housing with a first external contact (2) and a second external contact (2) for supplying power to the electrical device, wherein the electrical device comprises a first conductor (4), a second conductor (5) and an evaluation means (9) in the housing, wherein the first conductor (4) is electrically connected to a first contact (2) for a first potential, wherein the second conductor (5) is electrically connected to a second contact (2) for a second potential that is different from the first potential, wherein the first conductor (4) and the second conductor (5) are electrically connected to the evaluation means (9), wherein the first conductor (4) and the second conductor (5) are arranged in such a way that an electrical connection between the first conductor (4) and the second conductor (5) due to dirt or moisture in the housing can be detected by means of the evaluation means (9), wherein the second conductor (5) is electrically connected via a resistor (8) to an input of the evaluation means (9) for detecting dirt or moisture, wherein the evaluation means (9) is designed to identify a fault situation when an electrical connection between the first conductor (4) and the second conductor (5) due to dirt or moisture has been detected, characterized in that the evaluation means (9) is designed to deactivate the electrical device in the event of a fault, and in that the first conductor (4) and the second conductor (5) are two adjacent conductor tracks that are not insulated against an area surrounding the printed circuit board (1).

2. Electrical device according to Claim 1, characterized in that the second conductor (5) is electrically connected via a resistor (7) to the second contact (2) and an input of the evaluation means (9) for a supply voltage.

3. Electrical device according to either of Claims 1 and 2, characterized in that the first conductor (4) is electrically connected to an input of the evaluation means (9) for a reference potential.

4. Electrical device according to any of Claims 1 to 3, characterized in that the first conductor (4) and the second conductor (5) are arranged in a manner electrically insulated from each other and in one region adjacent to and uninsulated from each other at least in sections.

5. Electrical device according to Claim 1, characterized in that the electrical device comprises a battery cell and a discharge means, wherein the evaluation means (9) is designed to discharge the battery cell using the discharge means in the event of a fault.

6. Electrical device according to Claim 1, characterized in that the electrical device comprises a charging means for a battery cell, wherein the evaluation means (9) is designed to deactivate the charging means in the event of a fault or wherein the evaluation means (9) is designed to prevent charging of a battery cell by a charging means in the event of a fault.

7. Electrical device according to any of the preceding claims, characterized in that different pairs of first conductor (4) and second conductor (5) are arranged electrically insulated from each other in the electrical device, the different pairs being electrically connected to different inputs of the evaluation means (9), wherein the evaluation means (9) is designed to determine a number of pairs for which the electrical connection is detected, wherein the evaluation means (9) is designed to determine a fault situation of the electrical device depending on the number.

8. Electrical device according to any of the preceding claims, characterized in that a first conductor and plurality of second conductors are arranged adjacent to each other and electrically insulated from each other in the electrical device, wherein the evaluation means (9) is designed to determine a number of second conductors for which the electrical connection of the first conductor (4) to the second conductor (5) is detected, wherein the evaluation means (9) is designed to determine a fault situation of the electrical device depending on the number.

9. Method for operating an electrical device in which at least one first conductor (4), at least one second conductor (5) and an evaluation means (9) are arranged, wherein the at least one first conductor (4) is electrically connected to a contact (2) for a first potential, wherein the at least one second conductor (5) is electrically connected to a contact (2) for a second potential that is different from the first potential, wherein the electrical device is supplied with power by means of the contacts, wherein the at least one first conductor (4) and the second conductor (5) are electrically connected to the evaluation means (9), wherein the at least one first conductor (4) and the at least one second conductor (5) are arranged in such a way that an electrical connection between at least one first conductor (4) and at least one second conductor (5) due to dirt or moisture can be detected by means of the evaluation means (9), wherein a fault situation is identified (604) when an electrical connection between at least one first conductor (4) and at least one second conductor (5) due to dirt or moisture is detected (602) by means of the evaluation means (9), wherein in the event of a fault a user is warned by a display device, further use of the electrical device is blocked or restricted, a contamination event is stored for any warranty assessment, the electrical device is deactivated, a battery cell is discharged using a discharge means or a charging means is deactivated (606) or charging using a charging means is prevented (606).