Electronic component for inrush current limiting and use of an electronic component

Abstract

electronic component (1) comprising inrush current limiting - at least one NTC element (2), - at least two electrically conductive contact elements (3), wherein the NTC element (2) is electrically connected to the respective contact element (3) via a connecting material (7) and wherein the coefficient of thermal expansion of the respective contact element (3) is adapted to the coefficient of thermal expansion of the NTC element (2), wherein the NTC element (2) has a top and a bottom, wherein the NTC element (2) is arranged between the two electrically conductive contact elements (3) such that the top and the bottom of the NTC element (2) are each completely covered by one of the contact elements (3).

Description

[0001] The invention relates to an electronic component for limiting inrush current. The invention further relates to the use of an electronic component.

[0002] Start-stop systems in the automotive sector (cars, trucks) represent a significant way to save fuel and are therefore installed in almost all new vehicles. With these systems, the starter motor's inrush current must be limited to prevent a drop in the vehicle's electrical system voltage, ensuring that safety-relevant applications (ABS, ESP) are adequately powered.

[0003] A thermally controlled inrush current limiter (ICL) can be used for the starting process of an internal combustion engine. When the engine restarts after being shut down for fuel economy, the starter motor's current draw places a brief load of up to 1000 A on the 12 V electrical system. This additional load puts such a strain on typical 12 V batteries that the system voltage drops by several volts. This drop can cause other electrical components in the vehicle's electrical system to fail. To prevent this, the voltage drop must be avoided or reduced. For example, an NTC (Negative Temperature Coefficient) component can be used to reduce the voltage drop.

[0004] Given the expected dimensions of more than 1 cm 2Due to the small cross-section and length of less than 1 mm of the NTC component, a flat contact with low electrical resistance is necessary. Furthermore, the component is subject to significant temperature fluctuations during operation, and the coefficient of thermal expansion of the ICL ceramic is considerably lower than that of good electrical conductors (e.g., copper). The resulting thermal mechanical stresses can lead to the component's destruction.

[0005] JP H04-70701 U discloses a thermistor comprising a rectangular thermistor chip, wherein electrodes are vapor-deposited on two opposite sides of the thermistor chip and are electrically connected to leads. JP 2011-222737 A shows a thermistor in which the top and bottom of an NTC element are each partially covered by a lead wire.

[0006] One task to be solved is to specify an improved electronic component for inrush current limiting, as well as the use of an improved electronic component.

[0007] This problem is solved by the electronic component according to claim 1 and the use according to claims 17 and 18 respectively.

[0008] According to one aspect, an electronic component, or simply component, is specified. This electronic component is designed to be used in an inrush current limiter or to act as an inrush current limiter. The component has at least one NTC element. The NTC element serves as the functional element or functional layer of the component. The NTC element consists of an NTC ceramic. The component can have a number of NTC elements, for example, two, three, five, or ten NTC elements. The NTC element can be disc-shaped or plate-shaped (round). However, the NTC element can also have a rectangular or ring-shaped surface.

[0009] A metallization is applied to the NTC element, preferably to a top and a bottom surface. The metallization preferably consists of silver. Alternatively, the metallization can also consist of copper or gold. The NTC element can be a monolithic component. In this case, the NTC ceramic is manufactured using press technology and then lapped (fine grinding of both sides) to achieve the desired shape or thickness (thick-film monolith). Alternatively, the NTC element can also be designed as a multilayer monolith. In this case, ceramic sheets are stacked and pressed to form the NTC element.

[0010] The component has at least two electrically conductive contact elements or electrodes. The contact elements are planar. The contact elements are designed and arranged for electrical and thermal connection with the NTC element. The component can have a plurality of contact elements, for example, five, ten, or fifteen contact elements, whereby the individual NTC elements must be thermally well coupled.

[0011] The NTC element is electrically connected to the respective contact element via a connecting material. The NTC element is also thermally connected to the respective contact element via this connecting material. The connecting material creates a stable, highly electrically conductive, and mechanically durable connection between the NTC element and the contact elements.

[0012] The coefficient of thermal expansion of each contact element is matched to the coefficient of thermal expansion of the NTC element. Preferably, the coefficients of thermal expansion of the NTC element and the contact elements are approximately the same. For example, the NTC element has a coefficient of thermal expansion between 7 ppm / K and 10 ppm / K. Preferably, each contact element has a corresponding coefficient of expansion. The coefficient of thermal expansion of each contact element is preferably in the range between 5 ppm / K and 10 ppm / K.

[0013] By adjusting the coefficients of thermal expansion, the differences in material-related thermal expansion (CTE) between the NTC element and the contact elements are reduced or equalized. This minimizes or eliminates stresses caused by thermal expansion, resulting in a particularly stable, reliable, and durable component.

[0014] The NTC element has a top and a bottom. The top and bottom surfaces are opposite each other and can each be bounded by the end faces of the NTC element. The top and bottom surfaces are each fully electrically contacted by their respective contact elements. Depending on the manufacturing process, a small outer layer or a small edge area of ​​the top or bottom surface may remain uncontacted.

[0015] The top and bottom surfaces are each fully electrically contacted by their respective contact elements. In other words, the NTC element is embedded between the two contact elements, so that both the top and bottom surfaces are completely covered by a contact element. This ensures particularly reliable contact with the NTC element and a particularly stable connection between the NTC element and the contact elements.

[0016] According to one embodiment, the contact element comprises a composite material. In other words, the contact element is composed of several materials. The respective contact element preferably contains copper. Copper is characterized by its very high electrical conductivity and very high thermal conductivity. Additionally, the contact element preferably contains Invar and / or Kovar and / or molybdenum. These materials are characterized by their low coefficient of thermal expansion. Preferably, the respective contact element consists of a rolled copper-Invar sheet with a layered structure of copper-Invar-copper. By appropriately selecting the thickness ratio of the copper and Invar / Kovar or molybdenum layers of the respective contact element, the coefficient of thermal expansion can be matched to that of the NTC element. This results in a very stable and durable component.

[0017] According to one embodiment, the contact element has a layered structure of copper-Invar-copper with a thickness ratio of 10% ≤ copper ≤ 30% - 50% ≤ Invar / Kovar / molybdenum ≤ 80% - 10% ≤ copper ≤ 30%. This means that the contact element has at least three layers. A first layer preferably comprises copper. The first layer has a thickness or vertical extent that is between 1 / 10 and 3 / 10 of the total thickness of the contact element. A second layer preferably comprises Kovar and / or Invar and / or molybdenum. The second layer has a thickness that is between 5 / 10 and 8 / 10 of the total thickness of the contact element. The third layer has a thickness that is between 1 / 10 and 3 / 10 of the total thickness of the contact element.

[0018] The layer of the contact element containing invar / kovar / molybdenum is thicker than the layer containing copper. This allows the coefficient of thermal expansion of the contact element to be reduced or adjusted to match the coefficient of thermal expansion of the NTC element.

[0019] Preferably, the thickness ratio copper-Invar-copper is 20%-60%-20%. Of course, other thickness ratios, layer sequences, and numbers of layers, as well as the addition of Kovar or molybdenum, are conceivable to achieve the desired coefficient of thermal expansion.

[0020] According to one embodiment, the bonding material is sintered silver. Sintered silver exhibits high electrical and thermal conductivity. Furthermore, sintered silver can withstand high temperatures of up to 400 °C, for example 300 °C, as well as rapid and frequent temperature changes.

[0021] During operation, specifically in the hot state, the NTC element can experience very high temperatures and numerous temperature cycles. Therefore, the heat resistance and adaptability of the connecting material are of utmost importance. The hot state refers to a temperature higher than that of the NTC element in its ground state. The temperature range between the ground state and the hot state can, for example, span any temperature range between -55°C and +300°C or extend across this range. Preferably, the temperature range between the ground state and the hot state extends from -40°C to +300°C.

[0022] Preferably, the bonding material contains µAg. µAg is characterized in particular by its sufficient porosity.

[0023] According to one embodiment, the NTC element has two, three, five, ten, or more segments. The segments of the NTC element preferably represent rectangular sections of the element that are spaced apart from one another. The distance between the segments is 0.05 mm to 0.2 mm, for example, 0.1 mm. In other words, there are gaps (expansion joints) between the individual segments. These expansion joints prevent or minimize stress build-up. Additional mechanical stresses can thus be avoided, resulting in a durable component.

[0024] According to one embodiment, the NTC element has a nominal resistance R at a temperature of 25°C (room temperature). 25≤ 1 Ω. Room temperature is understood here to be the temperature typically found in inhabited rooms. The stated electrical resistance preferably describes the electrical resistance of the unloaded NTC element between external contacts at an ambient temperature of 25°C.

[0025] For example, the NTC element has a nominal resistance R at the specified temperature. 25 The resistance is less than or equal to 0.1 Ω, preferably less than 0.05 Ω. Consequently, the NTC element exhibits very low electrical resistance at room temperature or at 25°C and therefore very high electrical conductivity. This makes the NTC element particularly well-suited for use in an inrush current limiter with high current loads.

[0026] The low electrical resistance makes it possible, in particular, to ensure that a sufficiently high inrush current is available for an electrical load, which, for example, is connected in series with the electronic component in a corresponding application, while limiting it to such an extent that the voltage during the switch-on process remains sufficiently high to supply power to other important electrical components. With the help of the component, the voltage drop during the start-up of the load is preferably reduced by approximately 1 V compared to a load without the electronic component.

[0027] According to one embodiment, the specific electrical resistance of the NTC element in a ground state of the electronic component is ≤ 2 Ωcm. Preferably, the specific electrical resistance of the NTC element in a ground state of the electronic component is between 0.1 Ωcm and 1.0 Ωcm, for example 0.3 Ωcm.

[0028] According to one embodiment, the contact element has a thickness d. Preferably, 0.3 mm ≤ d ≤ 0.8 mm. Preferably, the thickness d of the respective contact element is less than 0.7 mm, for example 0.6 mm.

[0029] According to one embodiment, the component comprises a plurality of NTC elements and contact elements. The multiple NTC elements can be provided by singulating them from a substrate. The NTC elements are connected in parallel. The current-carrying capacity of the component can be increased by connecting several NTC elements in parallel. Preferably, the NTC elements are arranged stacked on top of each other. A contact element is arranged between each pair of adjacent NTC elements. The NTC elements are thermally coupled to each other via the contact elements.

[0030] According to one embodiment, the NTC element has the composition La (1-x) EA (x) Mn (1-a-b-c) Fe (a) Co (b) Ni (c) O (3±δ)where 0 ≤ x ≤ 0.5 and 0 ≤ (a+b+c) ≤ 0.5. EA denotes an alkaline earth element. Preferably, the alkaline earth element is selected from magnesium, calcium, strontium, or barium. δ denotes the deviation from the stoichiometric oxygen ratio (oxygen excess or oxygen deficit). Preferably, |δ| ≤ 0.5. Particularly preferably, |δ| = 0.

[0031] This composition provides an NTC element characterized by exceptionally high electrical conductivity and a sufficient B-value (thermistor constant). The resistance can be further varied and controlled by adjusting the specific thickness and cross-section or area of ​​the NTC element. The NTC element has a thickness d. Preferably, 100 µm ≤ d ≤ 600 µm. Preferably, the thickness d of the NTC element is less than 500 µm, for example, 400 µm. The B-value B 25 / 100lies in the range between 1000 K and 4000 K, preferably between 1400 K and 2000 K, for example at 1500 K.

[0032] According to one embodiment, the component has a fastening element. The fastening element is preferably designed and arranged to establish an electrically conductive connection with battery leads. The fastening element is further preferably designed and arranged to establish a mechanical connection with battery leads. The fastening element is also preferably designed and arranged to provide an indirect mechanical connection between the contact elements.

[0033] The fastening element can be designed to form a screw connection. Alternatively, it can be designed to form a clamping connection. The fastening element can also include a sealing element. The sealing element can be insulating or partially insulating. The fastening element can include at least one nut and one screw and / or at least one clamping element, for example, two clamping elements.

[0034] The fastener exhibits electrical resistance. This resistance is equal to or only slightly higher than the resistance of the NTC element at low operating temperatures. In particular, the electrical resistance of the fastener is equal to or only slightly higher than the resistance of the NTC element at the lowest operating temperature, e.g., -40°C.

[0035] The resistance of the mounting element is not temperature-dependent. Therefore, even in the event of a fault (e.g., a break in the conductive connection between the NTC element and the contact element), the engine can still be started (depending on the design of the starter system). Voltage dips are also avoided; however, the electrical power available for starting is severely limited, which may significantly delay the starting process. In addition to a screw connection, a fixed resistor or another conductive element with a defined electrical resistance can also be used as a mounting element.

[0036] According to another aspect, the use of an electronic component is described. Preferably, the use of the component described above is specified. All features explained in connection with the component also apply to its use, and vice versa.

[0037] The use of the component described above for start / stop systems in the automotive sector is specifically mentioned. The temperature-dependent resistor (NTC element) limits the inrush current during power-up. Upon power-up, the NTC element heats up immediately due to the inrush current (e.g., to 250°C), causing its resistance to rapidly decrease to a very low residual resistance (e.g., 0.5 mΩ). Due to the specific properties of the NTC element, this dynamic change in resistance reduces the current spike caused by the starter motor, which simultaneously reduces the voltage drop in the battery. This provides an effective component for limiting the inrush current in start-stop systems.

[0038] The provided contact elements and connecting material ensure a very low-resistance electrical connection between the NTC element and the contact elements for repeated switching cycles, even under ambient temperature fluctuations from -40°C to 120°C. During a switching cycle, the temperature can rise to 300°C. This results in a stable, highly electrically conductive component with a mechanically durable, temperature-resistant, and extremely resilient connection between the NTC element and the contact elements, suitable for use in automotive start / stop systems.

[0039] According to another aspect, the use of an electronic component, in particular the electronic component described above, is specified for currents up to 1000 A at DC voltage in 12 V and 24 V networks.

[0040] The invention will be explained in more detail below with reference to exemplary embodiments and the corresponding figures.

[0041] The drawings described below are not to be considered as being to scale. Rather, individual dimensions may be enlarged, reduced, or distorted for better illustration.

[0042] Elements that are identical or that perform the same function are designated with the same reference symbols. Fig. Figure 1 shows a schematic sectional view of an electronic component. Fig. Figure 2 shows a perspective view of a possible contacting of the electronic component according to Fig. 1, Fig. Figure 3 shows a perspective view of an electronic component according to a further embodiment, Fig. Figure 4 shows a schematic sectional view of an electronic component according to a further embodiment, Fig. Figure 5 shows a perspective view of a possible contacting of the electronic component according to Fig. 4, Fig. Figure 6 shows a schematic sectional view of an electronic component according to a further embodiment, Fig. Figure 7 shows a perspective view of an electronic component according to a further embodiment, Fig. Figure 8 shows a schematic sectional view of an electronic component according to a further embodiment, Fig. Figure 9 shows a top view of a section of the electronic component according to Fig. 8, Fig. Figure 10 shows a schematic sectional view of an electronic component according to a further embodiment, Fig. Figure 11 shows a top view of a partial area of ​​the electronic component according to Fig. 10, Fig. Figure 12 shows a schematic sectional view of an electronic component according to a further embodiment, Fig. Figure 13 shows a top view of a partial area of ​​the electronic component according to Fig. 12.

[0043] The Fig. Figure 1 shows an electronic component 1, or component 1 for short. Component 1 is designed to be used as an inrush current limiter or in an inrush current limiter for start / stop systems in 12 V and 24 V networks in the automotive sector. Component 1 is particularly suitable for use with currents up to 1000 A (at DC voltage in 12 V and 24 V networks). Component 1 is suitable for use in typical 12 V starter motors with a power output of approximately 1 kW to 3 kW.

[0044] Component 1 includes an NTC element 2, or an NTC ceramic. NTC element 2 represents a functional layer or element of component 1. NTC element 2 is a thermally conductive component with a negative temperature coefficient.

[0045] The NTC element 2 has a material composition characterized by high electrical conductivity and / or low specific resistance.

[0046] The NTC element 2 preferably has the following composition: La (1-x) EA (x) Mn (1-a-b-c) Fe (a) Co (b) Ni (c) O (3±δ)Here, 0 ≤ x ≤ 0.5 and 0 ≤ (a+b+c) ≤ 0.5. EA represents an alkaline earth element, for example Mg, Ca, Sr, or Ba. δ denotes the deviation from the stoichiometric oxygen ratio (oxygen excess or oxygen deficit). Preferably, |δ| ≤ 0.5, and particularly preferably, |δ| = 0. For example, NTC ceramic has the composition La 0,95 Sr 0,05 MnO3.

[0047] The specific electrical resistance of the NTC element 2 in its ground state is less than or equal to 2 Ωcm, preferably ≤ 1 Ωcm, for example 0.5 Ωcm. The ground state describes a temperature of 25°C for the NTC element 2, or room temperature. The ground state can be an unloaded state, in which, for example, no electrical power is applied to the NTC element 2.

[0048] The NTC element 2 exhibits an electrical resistance (nominal resistance R) at the specified temperature. 25) of less than or equal to 1 Ω, preferably less than 0.1 Ω, for example 0.05 Ω. The NTC element 2 therefore exhibits low electrical resistance at room temperature or at 25°C and thus high electrical conductivity. This makes the NTC element 2 particularly well-suited for use in an inrush current limiter.

[0049] Furthermore, NTC element 2 exhibits a high B-value. The B-value B 25 / 100 The operating temperature is in the range between 1000 K and 4000 K, preferably between 1400 K and 2000 K, for example at 1500 K. The NTC element 2 has a low coefficient of thermal expansion. Typically, the coefficient of thermal expansion of the NTC element 2 is between 7 ppm / K and 10 ppm / K.

[0050] The NTC element 2 is preferably designed as a monolithic component. For example, the NTC element 2 is a thick-film monolith. In this case, the NTC element 2 is manufactured using press technology and then brought to the desired thickness by lapping (fine grinding on both sides). Alternatively, the NTC element 2 can also be designed as a multilayer monolith. In this case, ceramic films are stacked on top of each other and pressed to form the NTC element 2.

[0051] The in Fig. The NTC element 2 shown has a round shape. The NTC element 2 is disc-shaped or plate-shaped. However, other shapes are also conceivable for the NTC element 2, for example, a rectangular shape or a ring shape. The NTC element 2 can be in the form of a substrate. The NTC element 2 has an area of ​​between 25 mm². 2 and 500 mm 2 , for example 200 mm 2The diameter of NTC element 2 is, for example, less than or equal to 14 mm, e.g., 13.75 mm. NTC element 2 has a thickness d between 100 µm and 600 µm, for example, 400 µm. By varying the thickness d and / or cross-section or area of ​​NTC element 2, its resistance can be varied and controlled.

[0052] The NTC element 2 has a metallization (not explicitly shown). The metallization is preferably arranged on a top and a bottom surface of the NTC element 2. Preferably, the metallization consists of baked-on silver.

[0053] The component 1 also has two contacts 3 or contact elements 3 (positive contact and negative contact element 12b, 12a, see Fig. 3) The contact elements 3 serve to electrically contact the NTC element 2. In this embodiment, the contact elements 3 lie completely on the top and bottom surfaces of the NTC element 2. Alternatively (not explicitly shown), a narrow edge area of ​​the top and bottom surfaces can also remain free of the respective contact element 3.

[0054] The contact elements 3 are each electrically connected to the top and bottom surfaces of the NTC element 2. Preferably, the NTC element 2 and the contact elements 3 are sintered together.

[0055] For this purpose, the component 1 has a bonding material 7. A layer of bonding material 7 is formed between the top surface of the NTC element 2 and the first contact element 3, and also between the bottom surface of the NTC element 2 and the second contact element 7. The layer thickness of the bonding material 7 is preferably in the range between 15 µm and 80 µm, for example 20 µm.

[0056] The bonding material 7 is characterized by high electrical and thermal conductivity. Furthermore, the bonding material 7 is preferably characterized by high porosity. The bonding material 7 is also characterized by its ability to withstand high temperatures up to 400 °C, e.g., 300 °C, as well as numerous and rapid temperature changes that may occur during operation or when the component 1 is hot.

[0057] The "hot state" refers to a state of component 1 at a temperature higher than that of component 1 in its ground state. The temperature range between the ground state and the hot state can, for example, span any temperature range between -55°C and +300°C or extend over this range. Preferably, the temperature range between the ground state and the hot state can extend over the range from -40°C to +300°C.

[0058] For example, the connecting material 7 is sintered silver Ag or µAg. Sintered silver has the advantage of sufficient porosity. Using connecting material 7, a stable, highly electrically conductive, and mechanically durable connection is achieved between the NTC element 2 and the contact elements 3.

[0059] The respective contact element 3 exhibits high thermal and electrical conductivity. Furthermore, the respective contact element 3 is designed to reduce thermal stresses between the NTC element 2 and the contact element 3. In particular, the respective contact element 3 is designed to reduce the differences in material-related thermal expansion (CTE).

[0060] Preferably, the respective contact element 3 comprises a composite material. The contact element can, for example, be designed as a composite sheet. The composite material can consist of copper-invar-copper (CIC). Instead of invar, kovar or molybdenum can also be used as the material. Invar, kovar, and molybdenum, respectively, have a low coefficient of thermal expansion. Typically, the coefficient of thermal expansion of these materials is ≤ 10 ppm / K, for example, 7 ppm / K. Thus, the coefficient of expansion of kovar / invar / molybdenum is very similar to the coefficient of expansion of the NTC element 2. By appropriately selecting the thickness ratio of the layers of the composite material, the coefficient of expansion of the contact element 3 can be closely matched to the coefficient of expansion of the NTC element 2. Thermal stresses can be reduced or avoided.

[0061] In this embodiment, the respective contact element 3 is a rolled copper-Invar sheet with a copper-Invar-copper layer structure of 20%-60%-20%. However, other ratios of copper and Invar or Kovar / Molybdenum are also conceivable. In particular, depending on the required area of ​​the NTC element 2 and the required thermal resistance, other layer sequences and layer thicknesses can also be used.

[0062] The contact elements 3 enclose the NTC element 2 in a pincer-like manner. A first sub-section 3a of each contact element 3 rests on the top or bottom surface of the NTC element 2 and extends parallel to the top or bottom surface of the NTC element 2 or to a longitudinal axis L of the component 1. The length or horizontal extent of the NTC element 2 is preferably less than or equal to the length or horizontal extent of the first sub-section 3a.

[0063] A second sub-section 3b of the respective contact element 3 forms an angle with the longitudinal axis L. The second sub-section 3b preferably joins the first sub-section 3a at an angle of ≤ 20°, for example 15°, to the longitudinal axis L of the component 1. The angle between the second sub-section 3b of the first contact element 3 and the second sub-section 3b of the second contact element is preferably less than or equal to 40°, for example 30°. A third sub-section 3c of the respective contact element 3 joins the second sub-section 3b and runs parallel to the longitudinal axis L.

[0064] In this embodiment, the respective sub-sections 3a, 3b, 3c preferably have the same length. For example, sub-sections 3a, 3b, 3c each have a length of 10 mm to 15 mm. The respective sub-sections 3a, 3b, 3c preferably have the same thickness d. For example, sub-sections 3a, 3b, 3c each have a thickness d of less than or equal to 0.8 mm and greater than or equal to 0.3 mm. Consequently, the thickness d of the respective contact element 3 is 0.3 mm ≤ d ≤ 0.8 mm, for example, d = 0.7 mm.

[0065] Sub-areas 3a, 3b, and 3c merge seamlessly into one another. In other words, sub-areas 3a, 3b, and 3c are not designed as separate areas or components but merely represent subsections of the respective contact element 3.

[0066] The respective contact element 3, in particular the third sub-area 3c, has a recess 8. Preferably, the third sub-area 3c has a larger horizontal extent or a larger area than the first and second sub-areas 3a, 3b (see, for example, Figure 1). Fig. 3) The recess 8 is preferably circular. The recess 8 has, for example, a diameter of 8 mm. The recess 8 completely penetrates the contact element 3. The recess 8 serves to connect the component 1 to battery leads by means of a fastening element, as for example in connection with Fig. 2 will be explained in more detail.

[0067] The Fig. Figure 2 shows a possible contact arrangement of component 1 according to the Fig. 1. Connect the battery leads via cable lugs.

[0068] Component 1 includes a fastening element for establishing electrical contact with component 1 and, in particular, for mechanically fastening battery leads to component 1. The fastening element can be configured to provide a screw connection as described below. Alternatively, the fastening element can also be configured and arranged to create a clamp connection.

[0069] A spacer 9 is arranged between the first and second contact elements 3. The spacer 9 is positioned between the underside of the third sub-area 3c of the first (upper) contact element 3 and the top side of the third sub-area 3c of the second (lower) contact element 3. The spacer 9 is cylindrical.

[0070] The spacer 9 is designed to be insulating. The spacer 9 serves as electrical insulation between the two contact elements 3 (positive contact element 12b and negative contact element 12a, see figure). Fig. 3) The spacer 9, for example, comprises polytetrafluoroethylene (PTFE). PTFE has the advantage of being a constant insulator up to a temperature of approximately 250°C. Preferably, the spacer 9 has a recess (not explicitly shown) that completely penetrates the spacer 9 in the vertical direction. The recess serves to receive a connecting element, e.g., a threaded rod 11, for example, a screw.

[0071] A nut 10 is arranged on the upper side of the first contact element 3 and on the lower side of the second contact element 3. Threaded rod 11 and nuts 10 serve to screw the contact elements 3 together and to provide an electrically conductive and mechanical connection between the component 1 and the battery leads (not explicitly shown). Alternatively, clamping elements could be provided, for example, to clamp the contact elements 3 and / or to provide an electrically conductive and mechanical connection between the component 1 and the battery leads (not explicitly shown).

[0072] Cable lugs 5 are arranged between the battery leads (not shown) and the contact elements 3. A copper cable (not shown) is attached to the cable lugs 5. The cable lugs 5 are electrically connected to the contact elements 3. To connect the component 1 to the cable lugs 5, the threaded rod 11 is guided through the nuts 10, the recess 8 in the respective contact element 3, and the recess in the spacer 9.

[0073] The screw connection on one axis avoids additional mechanical stresses on the connection between the NTC element 2 and the contact elements 3. The screw connection or fastening must either have a higher resistance than the NTC element 2 or must be insulating (see, for example, [reference]). Fig. 12 and Fig. 13). Alternatively, the screw connection or fastening can also be made directly to a ground contact on the vehicle or the starter motor.

[0074] The temperature-dependent resistance of component 1 limits the inrush current during power-up. Upon power-up, the NTC element 2 heats up immediately due to the inrush current (e.g., to 250°C), causing its resistance to rapidly decrease to a very low residual resistance (e.g., 0.5 mΩ). This dynamic change in resistance reduces the current spike caused by the starter motor, which simultaneously reduces the battery voltage drop. This provides a stable, durable, and efficient component for inrush current limiting.

[0075] Component 1 can additionally be equipped with a so-called "fail-safe" function. For this purpose, the [missing information] is [missing information]. Fig. The screw connection shown is designed such that its electrical resistance is equal to or only slightly higher than the resistance of NTC element 2 at the lowest operating temperature, e.g., -40°C. The resistance of this screw connection is not temperature-dependent. Therefore, even in the event of a fault (e.g., a break in the conductive connection between NTC element 2 and contact element 3), the engine can still be started (depending on the design of the starter system). The voltage drop is also avoided; however, the electrical power available for starting is severely limited, which may significantly delay the starting process. Alternatively, a fixed resistor or another conductive element with a defined electrical resistance can be used instead of a screw connection.

[0076] The Fig. Figure 3 shows a perspective view of an electronic component according to a further embodiment. In contrast to component 1 from the Fig. 1 indicates that the component 1 is in accordance with Fig. 3 several NTC elements 2 as well as several contact elements 3.

[0077] Component 1 can contain up to ten NTC elements 2. The NTC elements 2 are each round or disc-shaped (see details on the Fig. 1) The NTC elements 2 are electrically connected in parallel.

[0078] The contact elements 3 are arranged between the NTC elements 2. The component 1 preferably has a layer sequence of alternating NTC elements 2 and contact elements 3 (positive contact elements 12b and negative contact elements 12a). The planar, "stack-like" sequence of contact element 3 / NTC element 2 / contact element 3 / NTC element 2, etc., ensures good thermal contact between the individual NTC elements 2. This good thermal contact enables uniform heating of the NTC elements 2.

[0079] The diameter of the NTC elements 2 can be smaller than the diameter of the one in Fig. The NTC element shown in Figure 1 is connected to the NTC element 2. This means that several smaller elements are connected. The stresses decrease with the size of the NTC element 2.

[0080] The fastening to the, preferably the screwing with the, battery terminals is preferably carried out on a common, insulating body (for example a spacer 9) in order to avoid additional mechanical stresses on the connection between the NTC elements 2 and the contact elements 3.

[0081] All other features of component 1 according to the Fig. 3, in particular the material, structure and function of NTC elements 2 and contact elements 3 as well as their connection via the connecting material 7 and the function of the component 1 correspond to those in connection with the Fig. 1 described characteristics.

[0082] The Fig. Figure 4 shows a schematic sectional view of an electronic component according to a further embodiment.

[0083] The following only describes the differences compared to component 1. Fig. 1 described. In particular, the features concerning the design of the NTC element 2 and the connection of NTC element 2 and contact elements 3 are described in section 1. Fig. 1 also for component 1 from Fig. 4. Application.

[0084] In this embodiment, the contact elements 3 are double-sided. Here too, each contact element 3 has three sub-areas 3a, 3b, 3c, wherein the second sub-area 3b and the third sub-area 3c are similar but oriented in the opposite direction to the first sub-area 3a.

[0085] The first sub-section 3a rests on the top or bottom surface of the NTC element 2 and runs parallel to the top or bottom surface of the NTC element 2 or to the longitudinal axis L. The length or horizontal extent of the NTC element 2 is less than or equal to the length or horizontal extent of the first sub-section 3a.

[0086] Preferably, the length of the first sub-section 3a in this embodiment is greater than the length of the first sub-section 3a according to the one in Fig. In the embodiment shown in Figure 1, the length of the first section 3a is, for example, 18 mm. The diameter of the NTC element 2 is, for example, less than or equal to 14 mm, e.g., 13.75 mm.

[0087] The second and third sub-areas 3b and 3c each adjoin a side or edge area of ​​the first sub-area 3a. In other words, the second sub-area 3b and the third sub-area 3c are formed adjacent to the left and right of the first sub-area 3a, respectively.

[0088] The second sub-section 3b and the third sub-section 3c each form an angle with the longitudinal axis L. Preferably, the second and third sub-sections 3b, 3c each form an angle of ≤ 90°, for example 60°, with the longitudinal axis L. Both the second sub-section 3a and the third sub-section 3c extend away from the longitudinal axis L. A vertical distance from an end section 13 of the third sub-section 3c or of the second sub-section 3b to the NTC element 2 is, for example, less than or equal to 18 mm, for example 15 mm.

[0089] Component 1 is designed as a mirror image about the axis L. The respective contact element 3 is also designed as a mirror image about a vertical axis V.

[0090] The design described above allows, for example, the electrical and thermal resistance of the contact elements 3 to be halved while using the same contact material. A further advantage of this design is the avoidance of temperature differences in the NTC element 2 due to "one-sided" heat dissipation via the contact elements 3, as is the case, for example, in the design according to [reference to relevant diagram]. Fig. 1.

[0091] All other features of component 1 according to the Fig. 4 correspond to those related to the Fig. 1 described characteristics.

[0092] The Fig. Figure 5 shows a perspective view of a possible contacting of the electronic component according to Fig. 4.

[0093] Component 1 is placed inside a housing 6. The housing 6 is frame-shaped. Component 1 is connected to the housing 6 by means of an insulated, flexible copper cable (not explicitly shown) (screwed, clamped, or similar). The connection is made as described in connection with the Fig. 2 described via the nuts 10, the threaded rod 11, which is inserted into the recess 8 of the respective contact element 3, and the electrically conductive connection of the contact elements 3 with cable lugs into which the copper cables are inserted. The copper cables are inserted into the housing 6 via recesses 6a on a top and a bottom of the housing 6.

[0094] The housing 6 has a mechanical strain relief 4 for the copper cables. The strain relief 4 can be arranged, for example, on a top and a bottom 4 of the housing 6. When mechanical tension is applied to the copper cables, the strain relief 4 ensures that no or only minimal forces act on the component 1 and, in particular, on the connecting material 7. Consequently, the component 1 is preferably held stress-free by the strain relief 4.

[0095] The Fig. Figure 6 shows a schematic sectional view of an electronic component according to a further embodiment.

[0096] Essentially, component 1 corresponds to component 1 from Fig. 4. However, in this embodiment, the contact elements 3 are not arranged symmetrically to the longitudinal axis L. Rather, the contact elements 3 are offset from each other by 90°. This allows for different installation situations.

[0097] All other features of component 1 according to the Fig. 6 correspond to those related to the Fig. 4 described characteristics.

[0098] The Fig. Figure 7 shows a perspective view of an electronic component according to a further embodiment.

[0099] Essentially, component 1 corresponds to component 1 from Fig. 6. However, component 1 exhibits according to Fig. 7. Several NTC elements 2 and several contact elements 3. The component 1 can have up to ten NTC elements 2, each of which is round or disc-shaped and electrically connected in parallel. The NTC elements 2 are arranged between the contact elements 3. The component 1 can, in particular, have a layer sequence of alternating NTC elements 2 and contact elements 3.

[0100] The Fig. Figure 8 shows a schematic sectional view of an electronic component according to a further embodiment. Fig. Figure 9 further shows a top view of a partial area of ​​the electronic component according to Fig. 8.

[0101] In contrast to the embodiment according to the Fig. In this process, an NTC element 2 is used, which has been divided or segmented into smaller NTC elements or segments 2a by sawing or scoring. The NTC element 2 has a multitude of segments 2a.

[0102] For the formation of segments 2a, the NTC element 2 exhibits a different behavior than in Fig. 1 preferably has a rectangular shape. For example, the NTC element 2 has a width and a height of less than or equal to 13 mm, for example 12.7 mm. The respective segment 2a is also preferably rectangular. Preferably, the respective segment 2a has a length and a width of approximately 2 mm each.

[0103] The contact elements 3 should also be rectangular for this design. This ensures that each contact element is designed according to the Fig. 8 and Fig. 9 is formed from three rectangular sub-areas 3a, 3b, 3c. The three sub-areas preferably have the same length, for example 15 mm.

[0104] Between the individual segments 2a, gaps or expansion joints 15 are formed (see Fig. 9) The expansion joints 15 have a width of 0.05 mm to 0.2 mm, for example 0.1 mm. These expansion joints 15 result in lower thermal stresses in the NTC element 2 during normal operation.

[0105] For the production of this variant, ceramic multilayer technology is suitable, in which an NTC substrate made of stacked ceramic foils is segmented before or after metallization by a process called "dicing". All other characteristics correspond to those associated with the Fig. 1 described characteristics.

[0106] The Fig. Figure 10 shows a schematic sectional view of an electronic component according to a further embodiment. Fig. Figure 11 shows a top view of a partial area of ​​the electronic component according to the Fig. 10.

[0107] This embodiment combines features of the embodiments according to the Fig. 4, as well as 8 and 9. In particular, the contact elements 3 - as in connection with the Fig. 4 - described, double-sided. The NTC element 2 is - as described in connection with the Fig. 8 and Fig. 9 described - divided into individual segments 2a. All further features correspond to those associated with the Fig. 4, Fig. 8 and Fig. 9 described characteristics.

[0108] The Fig. Figure 12 shows a schematic sectional view of an electronic component according to a further embodiment. Fig. Figure 13 shows a perspective view of a sub-area of ​​the electronic component according to Fig. 12.

[0109] In this embodiment, the contact elements 3 are as described in connection with Fig. 4 described as double-sided. The NTC element 2 is arranged between the first sub-area 3a of the contact elements 3 and is electrically and thermally connected to the contact elements 3 via the connecting material 7.

[0110] In this embodiment, the screw connection differs from the screw connection according to Fig. 2 is designed to be insulating. For this purpose, the NTC element 2 is designed in an annular shape. In other words, the NTC element 2 has a round, continuous recess. The first sub-section 3a of the respective contact element 3 also has a recess in this embodiment. The recesses of contact elements 3 and NTC element 2 are designed and arranged to allow the insulating screw connection of the contact elements 3. In particular, the recesses are provided for the insertion of a threaded rod 11 for screwing the contact elements 3 together.

[0111] On an outer surface of the first sub-area 3a, a spacer 9 is arranged which has a recess 9a ( Fig. 13). The respective spacer is, for example, a PTFE disc. The respective spacer has, for example, a diameter of 15 mm. A spacer 9 is arranged on a top side of the first sub-section 3a of the first or upper contact element 3. Another spacer 9 is arranged on a bottom side of the first sub-section 3a of the second or lower contact element 3. A nut 10 is arranged on each spacer 9. The threaded rod 11 is guided through the nuts 10, the recesses in the spacers 9, the NTC element 2, and the contact elements 3 for screwing the contact elements 3 together. An insulating element 14 is inserted into the recess of the NTC element 2 between the threaded rod 11 and the NTC element 2. The insulating element 14 can, for example, be AlO₂. x exhibit. For example, the insulating element 14 is AlO. xTube. This enables an insulating screw connection of component 1.

[0112] The electrical contacting of component 1 is carried out in the same way as in connection with the Fig. 2 described via the electrically conductive connection of the contact elements 3 with the battery leads via the cable lugs 5. The cable lugs are screwed to the contact elements 3 via the recesses 8 of the contact elements 3. Reference symbol list 1 Electronic component 2 NTC element / NTC ceramic 2a Segment 3 Contact / Contact element 3a First sub-area 3b Second sub-area 3c Third sub-area 4. Strain relief 5 cable lug 6 cases 6a Recess 7 Connecting material 8 recess 9 spacers 9a Recess 10 Mother 11 threaded rod 12a Negative contact element 12b Plus contact element 13 End area 14 Insulating element 15 Expansion joint L Longitudinal axis V Vertical axis

Claims

[1] Electronic component (1) comprising inrush current limiting - at least one NTC element (2), - at least two electrically conductive contact elements (3), wherein the NTC element (2) is electrically connected to the respective contact element (3) via a connecting material (7) and wherein the coefficient of thermal expansion of the respective contact element (3) is adapted to the coefficient of thermal expansion of the NTC element (2), wherein the NTC element (2) has a top and a bottom, wherein the NTC element (2) is arranged between the two electrically conductive contact elements (3) such that the top and the bottom of the NTC element (2) are each completely covered by one of the contact elements (3). [2] Electronic component (1) according to claim 1, wherein the contact element (3) comprises a composite material. [3] Electronic component (1) according to one of the preceding claims, wherein the contact element (3) comprises copper and wherein the contact element (3) comprises Invar. [4] Electronic component (1) according to one of the preceding claims, wherein the contact element (3) has a layer structure of copper - Invar - copper with a thickness ratio of 10% ≤ copper ≤ 30% - 50% ≤ Invar ≤ 80% - 10% ≤ copper ≤ 30%. [5] Electronic component (1) according to one of the preceding claims, wherein the connecting material (7) comprises sintered silver. [6] Electronic component (1) according to one of the preceding claims, wherein the NTC element (2) has two, three or more segments (2a). [7] Electronic component (1) according to one of the preceding claims, wherein the NTC element (2) has a nominal resistance R at a temperature of 25°C 25 exhibits ≤ 1 Ω. [8] Electronic component (1) according to one of the preceding claims, wherein the specific electrical resistance of the NTC element (2) in a ground state of the electronic component (1) is ≤ 2 Ωcm. [9] Electronic component (1) according to one of the preceding claims, wherein the contact element (3) has a thickness d, and wherein 0.3 mm ≤ d ≤ 0.8 mm. [10] Electronic component (1) according to one of the preceding claims, wherein the NTC element (2) has a thickness d, and wherein 100 µm ≤ d ≤ 600 µm. [11] Electronic component (1) according to one of the preceding claims, comprising a plurality of NTC elements (2) and contact elements (3), wherein the NTC elements (2) are connected in parallel to each other. [12] Electronic component (1) according to claim 11, wherein the NTC elements (2) are arranged stacked on top of each other, wherein a contact element (3) is arranged between two adjacent NTC elements (2) and wherein the NTC elements (2) are thermally coupled to each other via the contact elements (3). [13] Electronic component (1) according to one of the preceding claims, wherein the NTC element (2) has the composition La (1-x) EA (x) Mn (1-a-b-c) Fe (a) Co (b) Ni (c) O (3±δ) exhibits, where 0 ≤ x ≤ 0.5 and 0 ≤ (a+b+c) ≤ 0.5 and where EA is an alkaline earth element and δ is a deviation from a stoichiometric oxygen ratio, where the alkaline earth element (EA) is selected from magnesium, calcium, strontium or barium and / or where |δ| ≤ 0.

5. [14] Electronic component (1) according to one of the preceding claims, wherein the NTC element (2) has a coefficient of thermal expansion between 7 ppm / K and 10 ppm / K. [15] Electronic component (1) according to one of the preceding claims, comprising a fastening element (10, 11), wherein the fastening element (10, 11) has an electrical resistance which is equal to the resistance of the NTC element (2) at low operating temperatures. [16] Use of an electronic component (1) according to any one of claims 1 to 15 for start / stop systems in the automotive sector. [17] Use of an electronic component (1) according to any one of claims 1 to 15 for currents up to 1000 A at DC voltage in 12 V and 24 V networks.

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