Patent Application
20220393373
This application claims priority to both (1) European patent application no. EP 21 178 141.4, filed Jun. 8, 2021, which is incorporated herein by reference, and (2) German patent application no. DE 20 2021 103 079.8, filed Jun. 8, 2021, which is incorporated herein by reference.
The present invention relates to an electrical feedthrough including an outer base body with at least one through-hole, an insulating material received in the through-hole, and an inner electrical conductor extending through the insulating material.
Electrical feedthroughs can be used to guide electrical conductors into hermetically sealed environments or housings. To this end, a sealing connection between the outer base body, the insulating material, and the insulated inner electrical conductors is provided. Such feedthroughs can be designed, for example, as glass-to-metal seals (GTMS), in which case the insulating material is made from glass, and the base body and electrical conductors are made from metal.
Electrical feedthroughs, in particular GTMS, cover a wide range of applications, for example in electronics and electrical engineering. Some examples of applications are connectors, charging ports, e.g. for wearables, consumer electronics devices, platform applications, medical devices, e.g. pace makers, but also components for harsh environments such as oil and gas components.
Desired sealing properties of electrical feedthroughs, in particular GTMS, are, in particular, effective electrical insulation and have effective hermeticity, long-term reliability and/or resistance in specific environments, such as against corrosive substances, vibrations, or temperature fluctuations.
Achieving these properties with sufficient quality can become difficult in designs where electrical conductors are desired to have relatively large diameters in relation to the overall dimensions of the feedthrough and/or are to be arranged in high density. In electronics applications this may be the case, for example, if small dimensions of the feedthrough are desired while at the same time certain connection standards are to be met. Another example may be charging ports in which electrical conductors are desired to provide relatively large landing areas and/or high densities.
What is needed in the art is an electrical feedthrough for electrical conductors having relatively large diameters in relation to the dimension of the through-hole and/or the base body and/or are arranged in high density, while at the same time sealing properties, such as electrical insulation, hermeticity, and long-term reliability are optimized.
The present invention provides an electrical feedthrough including a base body having a first side and an opposed second side and at least one through-hole extending through the base body from the first side to the second side, an insulating material received in the at least one through-hole, the insulating material having a first surface on the first side of the base body and an opposed second surface on the second side of the base body, and an electrical conductor extending through the insulating material, the electrical conductor having a first diameter at the location of the first surface of the insulating material and a second diameter at the location of the second surface of the insulating material, wherein the first diameter of the electrical conductor is larger than the second diameter of the electrical conductor.
In other words, the diameter of the electrical conductor is larger on the first side of the base body and smaller on the second side of the base body. This allows to optimize the large-diameter side for desired conductor dimensions, while the smaller-diameter side and the profile of the electrical conductor between the two diameters can be optimized for sealing properties such as insulation, hermeticity, long-term reliability and/or resistance against physical or chemical influences.
The electrical conductor may end flush with the first surface of the insulating material on the first side of the base body or may be offset therefrom less than 500 μm, optionally less than 250 μm, optionally less than 100 μm, in particular such that the first surface of the insulating material is grinded flush with the electrical conductor or forms a meniscus which optionally transitions flush to the electrical conductor. In case of an offset, the electrical conductor may be either protruding or recessed with respect to the first surface of the insulating material.
Additionally or alternatively, the electrical conductor may protrude from the second surface of the insulating material on the second side of the base body, wherein the protrusion optionally is more than 500 μm, optionally more than 1 mm, or more than 2 mm.
The electrical conductor may have one or more distinct sections defining the profile of the electrical conductor including the first diameter on the first side of the base body, the second diameter on the second side of the base body and/or the diameter profile between these two diameters.
For example, the electrical conductor may have a first section including the location of the first diameter and extending from the first surface of the insulating material into the insulating material, wherein the first section of the electrical conductor optionally has a constant diameter.
Additionally or alternatively, the electrical conductor may have a second section including the location of the second diameter and extending from the second surface of the insulating material into the insulating material, wherein the second section of the electrical conductor optionally has a constant diameter.
Additionally or alternatively, the electrical conductor may have a tapered section between the location of the first diameter and the location of the second diameter, wherein the tapered section has a tapered diameter and wherein the tapered section optionally is located between the first section and the section within the insulating material.
The aforementioned first, second and tapered sections may be present individually or in any combination. For example, the electrical conductor may have first and second sections with a step transition, i.e. without having a tapered section in between. In another example, the electrical conductor may have a constant-diameter first section which is followed by a tapered section. In yet another example, the electrical conductor may have a tapered section which is followed by a constant-diameter second section, which may be referred to as a direct tapered case. It is also possible that the conductor only includes a tapered section, which may be referred to as a full tapered case. Optionally, due to the decreasing diameter of the electrical conductor from the first side of the base body to the second side of the base body, the amount of surrounding insulating material may increase from the first side to the second side.
The electrical conductor may have a length L between the location of the first diameter and the location of the second diameter, wherein the length L optionally is in the range of 0.2 mm to 10 mm, optionally in the range of 0.3 mm to 5 mm, optionally in the range of 1 mm to 3 mm.
In what follows, relations of lengths and diameters of the electrical conductor and/or sections thereof are provided which in experiments and computer simulations have been shown to be particularly suitable for providing what is needed in the art with respect to the present invention. In particular, it is referred to computer simulation results further below.
In case the electrical conductor has a first and/or a tapered section as mentioned above, the first section of the electrical conductor may have a length L1 and/or the tapered section of the electrical conductor may have a length L3, wherein the length L1, the length L3, or the length L1 +L3 is at least 0.1 mm, optionally at least 0.3 mm, optionally at least 0.6 mm.
In case the electrical conductor has a first and/or a tapered section as mentioned above, the first section of the electrical conductor may have a length L1 and/or the tapered section of the electrical conductor has a length L3, wherein the ratio L1/L, the ratio L3/L, or the ratio (L1+L3)/L is smaller than 0.7, optionally is smaller than 0.5, optionally is smaller than 0.35.
In case the electrical conductor has a second section as mentioned above, the second section of the electrical conductor may have a length L2, wherein the ratio L2/L is larger than 0.3, optionally is larger than 0.5, optionally is larger than 0.65.
In case the electrical conductor has first and tapered sections as mentioned above, the tapered section of the electrical conductor may have a length L3, wherein the ratio L3/L1 is between 1.25 and 3.0, optionally between 1.5 and 2.5, optionally between 1.75 and 2.25.
The ratio of the first diameter and the second diameter of the electrical conductor may be between 1.1 and 10, optionally between 1.25 and 3.5, optionally between 1.5 and 3.0, optionally between 1.75 and 2.75.
The first diameter may be at least 0.8 mm, optionally at least 1 mm, optionally at least 1.5 mm.
The second diameter may be at most 1 mm, optionally at most 0.8 mm, optionally at most 0.5 mm.
In case the electrical conductor has a tapered section as mentioned above, the tapered section of the electrical conductor may have a diameter tapering from the first diameter to the second diameter. Additionally or alternatively, the tapered section of the electrical conductor may be a linearly tapering diameter.
In order to increase the mechanical interlock of the electrical conductor with the insulating material, the electrical conductor may include a groove, wherein the groove optionally is located in the second section of the electrical conductor.
The present invention further provides an electrical feedthrough including a base body with at least two through-holes extending through the base body, the base body having a first side and an opposed second side, wherein in each of the at least two through-holes an insulating material is received, each insulating material having a first surface on the first side of the base body and an opposed second surface on the second side of the base body, and wherein in each of the at least two through-holes at least one electrical conductor extends through the respective insulating material. Each of the electrical conductors of the feedthrough may be designed according to one or more of the above-mentioned features. The electrical conductors of the feedthrough are optionally designed identical. However, depending on the application, the conductors may also be designed differently.
Generally, a feedthrough may includes at least two electrical conductors extending through the or each insulating material. Depending on the application, two or more conductors may be used, for example in charging ports or data transfer applications.
Generally, a distance between two electrical conductors may be less than 50 mm, optionally less than 10 mm, optionally less than 5 mm. Such distance may be present at the location of the second diameter, optionally at the location of the first diameter.
Generally, a distance between two electrical conductors may be more than 100 μm, optionally more than 150 μm, optionally more than 200 μm. Such distance may be present at the location of the first diameter, optionally at the location of the second diameter.
Generally, a distance between an electrical conductor and the base body may be less than 5 mm, optionally less than 2 mm, optionally less than 1 mm. Such distance may be present at the location of the second diameter, optionally at the location of the first diameter.
Generally, a distance between an electrical conductor and the base body may be more than 100 μm, optionally more than 150 μm, optionally more than 200 μm. Such distance may be present at the location of the first diameter, optionally at the location of the second diameter. Such distance may be beneficial to have a gap sufficient for flow of insulation material, e.g. glass.
In particular, the above-mentioned distances may refer to a minimum distance between two conductors or between a conductor and the base body, in particular in cases of eccentric conductor(s), off-center conductor location(s) and/or non-uniform through-hole diameter(s).
In some embodiments, the ratio of the surface area of the insulating material received in a trough-hole and the surface area of the electrical conductor or conductors in the respective through-hole on at least one of the sides of the base body, for example the first side, may be less than 15, optionally less than 10, optionally less than 5, or less than 4.
Generally, as mentioned before, the or each electrical conductor may have a first diameter DEC1 at the location of the first surface of the respective insulating material and a second diameter DEC2 at the location of the second surface of the respective insulating material, wherein the diameter(s) of each conductor may be different. Further, the or each through-hole may have a diameter DTH, which optionally is constant throughout the base body, or is tapered, optionally within a range of 2° to 10°, having a maximum diameter DTH, wherein the diameter(s) DTH of each through-hole may be different.
In some embodiments, the ratio DTH/DEC1 of at least one through-hole is at most 1.5, optionally is at most 1.3, optionally is at most 1.2, or is at most 1.11.
In some embodiments, the ratio DTH/DEC2 of at least one through-hole is at most 10, optionally is at most 5, optionally is at most 2.5.
It is noted that the or each through-hole may have a tapering diameter, optionally with a tapering angle in the range of 2° to 10°, wherein the tapering can be in either direction, that is the through-hole diameter may taper towards the second side of the base body or towards the first side of the base body. Advantages of tapered through-holes may in particular be higher pressure resistance and/or improved processing, such as easier part ejection after injection molding process.
In the case of more than one through-hole, each of the at least two through-holes may have a diameter DTH, and each of the at least two through-holes may define a half-distance diameter DBB, the half-distance diameter DBB being the distance ΔTH within the base body between adjacent through-holes plus the diameter DTH of the respective through-hole, wherein the ratio DBB/DTH of at least one through-hole is smaller than 2.0 optionally is smaller than 1.8, optionally is smaller than 1.7, or is smaller than 1.6, or is smaller than 1.5, or is smaller than 1.4, or is smaller than 1.3, or is smaller than 1.2, or is smaller than 1.1.
In case of tapering through-holes, these aforementioned diameters DTH and DBB may optionally be measured on the first side of the base body. Alternatively, however, they may be measured at the second side of the base body.
The aforementioned distances, surface ratios and diameter ratios have proven to be particularly favorable for providing what is needed in the art with respect to the present invention according to experiments and computer simulations. In particular, it is referred to computer simulation results further below.
In addition, experiments and computer simulations have been performed for the contact pressure on the insulating material, wherein negative contact pressure refers to contact tension.
In some embodiments, the insulating material may be under a contact pressure CP2 at the location of the second surface on the second side of the base body, wherein CP2 is a positive contact pressure, or wherein CP2 is a negative contact pressure with an absolute value being less than 30 MPa, optionally less 20 MPa, optionally less than 10 MPa, or less than 5 MPa.
In some embodiments, the insulating material may be under a contact pressure CP1 at the location of the first surface on the first side of the base body, wherein CP1 is a negative contact pressure with an absolute value being more than 1 MPa, optionally more than 5 MPa, optionally more than 10 MPa.
In some embodiments, the insulating material is under a highest positive contact pressure with an absolute value which is lower than 155MPa, optionally is lower than 70 MPa, optionally is lower than 50 MPa, optionally is lower than 40 MPa, optionally is lower than 20 MPa.
Generally, a feedthrough's base body may have a thermal expansion coefficient between 5×10−6K−1 and 25×106K−1, optionally between 5×10−6K−1 and 20×10−6K−1.
Generally, a feedthrough's insulating material may have a thermal expansion coefficient between 3×10−6K−1 and 15×10−6K−1, optionally between 5×10−6K−1 and 12×10−6K−1.
Generally, a feedthrough's electrical conductor may have a thermal expansion coefficient between 3×10−6K−1 and 25×10−6K−1, optionally between 5×10−6K−1 and 20×10−6K−1.
The base body may include at least one of the following materials: metal, austenitic stainless steel, optionally AISI 300 series, ferritic stainless steel, optionally AISI 400 series, titanium, inconel, duplex stainless steel, niobium, an alloy of one of the aforementioned metals, e.g. titanium alloy, ceramic. In case the base body includes metal and the insulating material includes glass, the feedthrough may be referred to as glass-to-metal seal. In case the base body includes ceramics and the insulation material includes glass, the feedthrough may be referred to as glass-to-ceramics seal.
The insulating material may include at least one of the following materials: glass, glass ceramic, ceramic.
The electrical conductor may include at least one of the following materials: metal, metal alloy, stainless steel 300 series, stainless steel 400 series, titanium, NiFe, NiFeCo alloy, niobium, copper, tungsten, molybdenum, platinum, an alloy of one of the aforementioned metals, e.g. titanium alloy or copper alloy.
In some embodiments, the base body and the electrical conductor may only include non allergic materials, wherein the base body and the electrical conductor optionally are free of nickel leaching.
In particular, the present invention relates to a charging port or medical port for electronic devices, in particular wearables, including an electrical feedthrough as described above.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring to
For several practical applications, it may be desired to provide feedthroughs 10 with relatively thick electrical conductors 40 in relation to the diameter of the through-hole DTH, to the distance between adjacent through-holes ΔTH and/or to a half-distance diameter DBB=DTH+ΔTH, while at the same time hermeticity, electrical insulation between conductors 40 and/or the base body 20 or other properties of the sealing should satisfy certain quality requirements.
Multiple approaches may be considered for this purpose. In particular, instead of using electrical conductors 40 with constant diameter DEC1=DEC2 (
For example, the first side 22 of the feedthrough 10 on which the electrical conductor 40 has a larger diameter DEC1 may be facing the exterior of a device, whereas the second side 24 of the feedthrough 10 on which the electrical conductor 40 has a smaller diameter DEC2 may be facing the interior of a device.
Such asymmetrical pin diameters (for example external and internal) may increase performance and/or optimize desired dimension ratios of the feedthrough 10. On the one hand, a larger pin external diameter DEC1 can provide higher contact area which may be beneficial for a mating contact area. This may be especially helpful in case of tolerances of a mating component, which may be pogo pins. On the other hand, a smaller internal pin diameter DEC2 may allow relatively small flex outlines. The internal pin end may be mated to another component through various ways, such as by soldering.
According to one embodiment, asymmetrical pin diameters DEC1>DEC2 may be realized with a step design (
In some cases of GTMS, where the insulation material 30 is glass, depending on the dimensions of the components of the feedthrough 10 and processes used, such step design may lead to situations during glass sealing process whereby the glass flow is insufficient to cover the entire cavity. In such cases bubbles or gaps may result at certain locations which creates risks of leakage. Also in some cases of GTMS, the sharp corners of the step pin design, may lead to high stress areas which may be prone to glass cracks which may also lead to risk for leakage.
However, such problems are only expected under specific conditions and/or dimensions of the components of the feedthrough 10 and can be solved by suitable processes and/or materials, as detailed further below.
Alternatively or additionally, a tapered pin design may be beneficial (
However, the electrical conductor 40 may also be designed to have a tapered section 46 with the first diameter DEC1 followed by a second section 44 with the second diameter DEC2 (
In addition, to allow for a stronger mechanical interlock between the insulation material 30 (e.g. glass) and the conductor 40, one or more grooves 48 can be implemented on the conductor 40 so that insulation material 30 can flow into the conductor to create e.g. a Velcro interlock.
Electrical conductors 40 may be produced for example by CNC, MIM and/or forging, in particular in the case of tapered designs.
Generally, asymmetric pin designs have shown to increase GTMS performance, for example mechanical robustness and/or hermeticity, in particular for the soldering area in glass-to-metal seal systems. Tapered pin designs may improve insulation material flow (lesser constriction areas) in production, and, thus, may reduce the risk of bubbles, cracks, and/or lower the stress due to less sharp corners, in particular for glass insulation material (GTMS).
Referring to
for a soldering process. Contact pressure has a direct relation to mechanical robustness and seal integrity of the feedthrough.
Four variants of pin/glass systems were constructed and analyzed to illustrate relationships between pin thickness, glass thickness and the robustness of the glass-to-metal seal system: A first variant refers to a glass/pin system with typical design guidelines, i.e. glass with nominal gap (
For these 4 variants, computer simulation results of the contact pressure on the insulation material (glass) are illustrated in
It is found that for the first variant 100, the insulation material has superior contact strain at its surfaces (x=0, x=2) as compared to the second and third variants 102, 103, where the insulation material is under negative contact pressure (i.e. contact tension). However, for the fourth variant 101 the insulating material has superior contact strain as compared to the second and third variants 102, 103. In particular, on the second surface (x=2), the insulation material is under negative contact pressure CP2 with an absolute value being lower as compared to the second and third variants 102, 103, or is under a positive contact pressure CP2.
Such contact pressure, in particular positive contact pressure, on the glass indicates a more robust glass sealing system which in turns help in the mechanical robustness of the pins on the second side (e.g. soldering side). This may be of particular advantage as pins at the soldering side are subjected to heat mechanical stresses during the soldering process.
In the nailhead design, the pressure does not get build up over the nail head pin system. Moreover, in the nail head pin system, the insulating material may be under highest positive contact pressure CP3 with an absolute value which is lower than 45 MPa, or lower than 35 MPa.
To support the aforementioned findings,
Referring to
In both cases, aforementioned pin designs enable systems with optimized sealing properties while at the same time distances ΔEC between two electrical conductors and/or distances ΔECBB between an electrical conductor and the base body may be decreased, in particular to allow for high density pin configurations (typically a lower pitch distance corresponds to a higher density of pins for a given area).
Additionally or alternatively, providing feedthroughs having decreased ΔEC, decreased ΔECBB and/or allow for a desired electrical conductor diameter in relation to DTH, ΔTH and/or DBB (
For example, the selection of metal housing may have an impact on the pin-to-pin (pitch) spacing. To achieve high levels of corrosion resistance and reliability performance, metals like stainless steel or Ti can be utilized. For metals with high CTE, e.g. 316L, pitch spacing may be higher compared to metals like stainless steel 400 series and Ti. For a low weight, high reliability, high density glass-to-metal seal and/or biocompatibility, Ti may be chosen as material for the base body and/or pins. The base body and/or the pins may be optionally Non-Ni materials or free of nickel leaching.
In one exemplary embodiment, the base body may include SS316L and DBB/DTH may be 1.6. In another exemplary embodiment the base body may include SS400 series/Ti and DBB/DTH may be 1.3.
In one exemplary embodiment, the base body may include SS316L and the conductor may include SS316L. In another exemplary embodiment the base body may include SS400 series/Ti and the conductor may include SS400 series.
While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2021 103 079.8 | Jun 2021 | DE | national |
| 21 178 141.4 | Jun 2021 | EP | regional |
