HEATING ELEMENT

Abstract

A heating element (1) is disclosed for heating a surrounding area. For this purpose, the heating element (1) has at least one measuring element (4) and two control contacts (8, 9) for supplying the heating element (1) and the measuring element (4) with electrical energy. The heating element (1) can now assume a first operating state in which the heating element (1) converts at least some of the electrical energy into heat and releases it to the surrounding area, and a second operating state in which the measuring element (4) is supplied with electrical energy and the heating element (1) is not supplied with electrical energy. These two operating states are controlled by the polarity of the voltage potential (+, -) of the electrical energy at the control contacts (8, 9).

Description

[0001] The present invention relates to a heating element and a method for operating the heating element to heat a surrounding area. Such heating elements are used in various environments, e.g., in the automotive sector, to keep mechanical components ice-free.

[0002] To detect whether ice is present or not, additional elements are required, such as measuring devices. These can detect the presence of ice, measure temperature, and / or take humidity measurements.

[0003] Such a heating element is disclosed, for example, in DE 28 18 055 A1. Here, humidity sensors are heated to establish a specific operating temperature.

[0004] A disadvantage of this type of heating element is its size due to the large number of sensors and connections.

[0005] Especially in the automotive sector, there are often only small installation spaces available for such a heating element and other elements, so space-saving development is necessary and the connection of the elements to the car can be achieved with minimal effort.

[0006] A specific application proposed here is the charging socket of vehicles with electrically rechargeable energy storage. This includes a mechanical locking mechanism that must function reliably even in cold temperatures. A heating element can be used to keep the mechanical lock free of ice and thus functional.

[0007] The object of the present invention is therefore to combine a heating element and the additional elements in a small installation space and to keep the number of connections as low as possible.

[0008] This problem is solved by the features of the present main claim.

[0009] A heating element is proposed that is suitable for warming the surrounding area. It is preferably proposed that the heating element be installed in a charging socket or inlet of a vehicle with an electrically rechargeable energy storage system.

[0010] The heating element includes two control contacts for supplying it with electrical energy. When electrical energy is supplied, the heating element converts it into heat and releases it into the surroundings. The heating element operates on a direct current (DC) voltage.

[0011] The heating element also includes at least one measuring element. These measuring elements are also connected via the same two control contacts and can be supplied with electrical energy via these contacts.

[0012] To operate energy-efficiently, the heating element can assume two operating states. In the first operating state, the heating element can convert at least some of the electrical energy into heat and release it to the surrounding area.

[0013] Preferably, the conversion of electrical energy to heat is realized by at least one heating wire, which heats up when electrical energy is supplied and can release this generated heat to the environment.

[0014] In a second operating state, the current flowing through the control contacts can be measured using a measuring device, and this current allows conclusions to be drawn about physical quantities such as temperature or humidity.

[0015] The two operating states are controlled via the electrical polarity of the voltage potential, which is applied to the control contacts for power supply.

[0016] To ensure that the current flow, which heats the heating element in the first operating state, does not influence the measurement in the second operating state and thus enables the aforementioned conclusion, a diode is provided which, in the second operating state, at least largely prevents the current flow through the part of the heating element that is needed to convert electrical energy into heat, e.g., through the heating wire.

[0017] The control contacts are distinguished by a positive control contact and a negative control contact. The electrical supply to the heating element is connected to these.

[0018] For the first operating state, an electrical voltage is applied to the control contacts, such that a positive voltage potential is applied between the positive and the negative control contact.

[0019] This ensures that the applied voltage potential is also applied to the measuring elements, which can be used, for example, to measure humidity or temperature. One of the measuring elements can, for instance, be designed as two contact points between which a leakage current would be measurable if moisture were present. Since moisture should not normally be present, no significant current flow should be observed through this measuring element in its initial operating state.

[0020] In its initial operating state, the diode is wired in such a way that electrical energy can flow from the control contacts to the part of the heating element used for converting electrical energy into heat, e.g., the heating wire. In this initial operating state, an electric current flows through this wire, which represents the electrical energy required for heat conversion.

[0021] By regulating or controlling the current supplied to the control contacts for energy supply, the amount of heat generated can also be regulated or controlled.

[0022] By reversing the polarity of the power supply at the control contacts, the diode is wired in such a way that, in the second operating state, the electrical energy from the control contacts cannot reach the part of the heating element used for converting electrical energy into heat, e.g., the heating wire. Therefore, in the second operating state, no electrical current flows through this part, thus preventing heat conversion.

[0023] In the first operating state, the heating element can heat its surroundings. In the second operating state, the measuring element can be used to measure physical quantities, such as humidity and / or temperature. Thus, two different functions are achieved in a single component—the heating element with just two control contacts—simply by reversing the polarity of the electrical power supply at the control contacts.

[0024] It is proposed to use the aforementioned contact points as measuring elements. These can be used to measure leakage currents between the contact points in the second operating state. If moisture is present between the contact points, it leads to a change in the electrical resistance between them. This resistance can be measured by increasing the current flow between the contact points. This allows verification of whether or not moisture is present between the contact points. The amount of moisture can also be inferred from the resistance value.

[0025] A further measuring element, a temperature-dependent resistor, such as a PTC (positive temperature coefficient thermistor), is proposed. This, like the contact points, is connected to the control contacts. This allows a temperature-dependent current through the contact points to be measured in the second operating state, from which conclusions can be drawn about the temperature at or within the heating element.

[0026] To enable or optimize temperature measurement of the area surrounding the heating element, it is proposed to couple the measuring element to the heating element via thermal coupling. For this purpose, the measuring element can be physically bonded to the heating element or to a housing of the heating element, for example, by gluing or screwing. The thermal conductivity can also be improved by using a thermally conductive material or coating the measuring element.

[0027] To measure the current through the control contacts in the second operating state, and thus to enable inferences about physical quantities, at least one measuring device can be used, which is inserted into a supply line to the control contacts. The current measured in this way can then be further evaluated by a microcontroller circuit.

[0028] Preferably, it is proposed to periodically control the two operating states by reversing the polarity of the power supply at the control contacts. This would allow for temperature regulation, which can be carried out depending on the measured temperature and / or the amount of humidity measured.

[0029] As an example, the first operating state can be entered periodically for 900 ms, followed by the second operating state for 100 ms. This sequence of both operating states is called a measurement cycle. Other control and measurement times are possible and depend on the design of the higher-level system.

[0030] Several functions can now be implemented with the proposed heating element: Function 1: Detection and prevention of moisture on the heating element

[0031] During the second operating state, a resistance measurement at one of the measuring elements can determine whether moisture is present on the heating element. This allows the conversion to heat in the first operating state to be activated depending on the moisture level. This prevents moisture from accumulating on the heating element. Function 2: Detection of overtemperature in the heating element and adjacent components

[0032] In the respective measurement cycle in the second operating state, a resistance measurement on one of the measuring elements can be used to determine whether there is an overtemperature in the heating element, and whether the conversion to heat should be switched off in the first operating state.

[0033] This prevents the heating element from damaging itself or adjacent components due to overheating. It also allows detection of whether the measured temperature is suitable for safe operation. Function 3: Activation condition for defrosting the surrounding area

[0034] During the second operating state of each measurement cycle, a resistance measurement at one of the measuring elements can determine whether the heating element, for example, has a temperature below 0°C. This can be used as a switch-on condition for heat conversion in the first operating state of the heating element, for example, to thaw a surrounding layer of ice around the heating element. Function 4: Heating a heating element

[0035] In its first operating state, the heating element can be used to heat the surrounding area by converting electrical energy into heat energy using a heating source, e.g. a heating wire.

[0036] Further features can be seen in the attached drawing. It shows: Fig. 1: Circuit diagram of a heating element according to the invention.

[0037] Fig.Figure 1 shows a heating element 1 according to the invention, which is suitable for heating the surrounding area. For this purpose, the heating element 1 can be placed in a housing, which is shown here as a dashed line.

[0038] The heating element 1 includes two control contacts 8, 9 for supplying the heating element 1 with electrical energy.

[0039] The heating element 1 further comprises at least one measuring element 4, 5, 6, wherein in this case the measuring element 4 is designed as a temperature-dependent resistor and the measuring elements 5 and 6 as contact points. These measuring elements 4, 5, 6 are also connected via the same two control contacts 8, 9 and can be supplied with electrical energy via these.

[0040] For the first operating state, the conversion of electrical energy to heat is realized by at least one heating source 2, which heats up when electrical energy is supplied and can release this generated heat to the environment.

[0041] To prevent the current flow which is directed through the heating source 2 to heat the heating element 1 in the first operating state and to prevent such a current flow in the second operating state, a diode 3 is provided.

[0042] The control contacts 8 and 9 are distinguished by a positive control contact 8 and a negative control contact 9. The electrical supply for the heating element 1 is connected to these. The corresponding electrical potential is shown at the heating source 2 in this figure.

[0043] For the first operating state, an electrical voltage is applied to the control contacts 8, 9, such that a positive voltage potential is applied between the positive 8 and the negative control contact 9.

[0044] This ensures that the applied voltage potential is also applied to the measuring elements 4, 5, 6, which can be used, for example, to measure humidity or temperature. For this purpose, one of the measuring elements 5 or 6 can, for example, be designed as two contact points between which a leakage current would be measurable if moisture were present.

[0045] In the first operating state, diode 3 is connected in such a way that electrical energy from control contacts 8, 9 can reach the part of heating element 1 that is used for converting electrical energy into heat, here the heating source 2. In the first operating state, this is then supplied with an electric current, which represents the electrical energy required for heat conversion.

[0046] By regulating or controlling the current supplied to control contacts 8 and 9 for energy supply, the amount of heat generated can also be regulated or controlled. However, such control is the responsibility of the higher-level system and is not shown here.

[0047] By reversing the polarity of the power supply at control contacts 8 and 9, diode 3 is connected in the second operating state such that the electrical energy from control contacts 8 and 9 cannot reach the part of the heating element 1 used for converting electrical energy to heat, in this case, the heating wire 2. Thus, after reversing the polarity, a negative voltage potential is applied to control contacts 8 and 9, such that a negative voltage potential is created between the positive contact 8 and the negative control contact 9. Control contact 8 now has a lower electrical potential than control contact 9.

[0048] The previously mentioned contact points 5 and 6 are also provided as measuring elements 4, 5, and 6. These can be used to measure leakage currents between contact points 5 and 6 in the second operating state. Due to the known magnitude of the voltage potential at the control contacts 8 and 9, as well as the magnitude of the leakage current to be measured, a resistance 7 arises between contact points 8 and 9 in the presence of moisture.

[0049] A further measuring element 4, a temperature-dependent resistor, e.g. a PTC, is used.

[0050] To measure the current through the control contacts in the second operating state, and thus to enable inferences about physical quantities, at least one measuring device can be used, which is inserted into a supply line to the control contacts. The current measured in this way can then be further evaluated by a microcontroller circuit. However, the microcontroller and measuring device are part of the higher-level system and are not shown in this figure. REFERENCE MARK LIST 1 heating element 2 Heat source 3 diode 4 measuring element 5 contact points + 6 Contact point - 7 Resistance 8 control contacts + 9 Control contact - + positive voltage potential Negative voltage potential QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 28 18 055 A1

[0003]

Claims

[1] Heating element (1) for heating a surrounding area, with at least one measuring element (4) and with two control contacts (8, 9) to supply the heating element (1) and the measuring element (4) with electrical energy characterized by , that the heating element (1) can assume a first operating state in which the heating element (1) converts the electrical energy at least partially into heat and releases it to the surrounding area, that the heating element (1) can assume a second operating state in which the measuring element (4) is supplied by means of the electrical energy and the heating element (1) is not supplied with electrical energy, and that the respective operating state assumed can be controlled by a polarity of the voltage potential (+, -) of the electrical energy at the control contacts (8, 9). [2] Heating element (1) according to claim 1, characterized by, that the heating element (1) comprises at least one heating source (2) which, in the first operating state, can convert the electrical energy at least partially into heat. [3] Heating element (1) according to claim 2, characterized by , that a diode (3) largely prevents current flow through the heating source (2) in the second operating state. [4] Heating element (1) according to one of claims 1 to 3, characterized by , that two contact points (5, 6) are included as one of the measuring elements (4) which are supplied with electrical energy and between which leakage currents can occur, which can be measured by means of a measuring device in the second operating state. [5] Heating element (1) according to claim 4, characterized by , that the leakage currents between the contact points (5, 6) form a resistance due to the electrical energy, which can be measured using the measuring device in the second operating state. [6] Heating element (1) according to any one of claims 1 to 5, characterized by , that one of the measuring elements (4) is designed as a temperature-dependent resistor. [7] Heating element (1) according to any one of claims 1 to 6, characterized by , that the electrical energy can be applied as direct current voltage to the control contacts (8, 9). [8] Heating element (1) according to claim 7, characterized by , that to assume the first operating state the control contact + (8) can be supplied with a positive voltage potential relative to the control contact - (9). [9] Heating element (1) according to claim 7, characterized by , that to enter the second operating state, the control contact + (8) can be supplied with a negative voltage potential relative to the control contact - (9). [10] Heating element (1) according to any one of claims 1 to 9, characterized by , that the measuring element (4) is coupled to the heating element (1) by means of a thermal coupling. [11] Heating element (1) according to claim 10, characterized by , that the thermal coupling can be implemented as a coating of the measuring element (4). [12] Heating element (1) according to any one of claims 1 to 11, characterized by , that a measuring device can measure the electric current through the control contacts (8, 9). [13] Method for operating a heating element (1) according to any one of claims 1 to 12, characterized by , that to assume the first operating state the control contact + (8) is supplied with a positive voltage potential relative to the control contact - (9) and to assume the second operating state the control contact + (8) is supplied with a negative voltage potential relative to the control contact - (9). [14] Method according to claim 13, characterized by that the operating states are assumed periodically. [15] Method according to claim 14, characterized by, that the amount of heat converted in the first operating state is controlled depending on at least one of the measured physical quantities that can be measured in the second operating state.

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