EP4717918A1

EP4717918A1 - Electrical feedthrough assembly

Info

Publication number: EP4717918A1
Application number: EP24202538.5A
Authority: EP
Inventors: Helmut Hartl
Original assignee: Schott AG
Current assignee: Schott AG
Priority date: 2024-09-25
Filing date: 2024-09-25
Publication date: 2026-04-01
Also published as: WO2026068328A1

Abstract

The present disclosure relates to electrical feedthrough assemblies in general, especially to electrical feedthrough assemblies that may be attached to a housing, preferably a housing for an E-compressor, an electrical storage device, a pressure sensor or the like. The feedthrough assembly 1 comprises a base body 3 with at least one through hole 5, wherein at least one pin 7 is arranged and sealed within the at least one through hole 5 by a sealing portion 9 made of insulating material. In order to increase the creepage distance between pin 7 and base body 3 an insulating sleeve portion 11 having an cylindrical part 13 is provided around the pin 7, wherein the sealing portion 9 and the insulating sleeve portion 11 are present in one piece in the form of an integral insulating element 15 made of insulating material wherein the insulating material comprises glass or consists of glass or is made of glass, and wherein the insulating sleeve portion 11 is sealed to the pin 7.

In particular, the present disclosure provides an electrical feedthrough assembly that is suited for high-voltage applications while at the same time having a robust design and good connectability.

Description

Field of invention

The present disclosure relates to electrical feedthrough assemblies in general, especially to electrical feedthrough assemblies that may be attached to a housing, preferably a housing for an e-compressor, an electrical storage device, a pressure sensor or the like. In particular, the present disclosure relates to electrical feedthrough assemblies that are suited for high-voltage applications.

Background of invention

An electrical feedthrough assembly usually comprises a base body made of a metal material, having a first and an opposite second side and comprising at least one through hole arranged within the base body. The though hole connects the first and the second side. A pin that is also made of metal is arranged within the through hole. The pin is electrically insulated from the base body and sealed in the through hole by a sealing element made of an insulating material so that at least one feedthrough is formed in the base body, wherein the sealing element extends between the pin and the base body and surrounds the pin. Thus, the pin is held by the sealing element in an electrical insulating way. The pin may then be electrically contacted. Such a feedthrough assembly may be employed in various applications such as in electrical storage devices such as batteries, in pressure sensors, compressors or the like. Preferably, the insulating material seals the pin within the through hole so that a preferably fluid-tight seal is achieved.
Various attempts have been made to optimize such electrical feedthrough assemblies in order to adapt them for a wide range of applications. In recent years, applications for feedthrough assemblies tend to be miniaturized while at the same time the feedthrough is applied in high voltage distance environments, thereby increasing the need of small, yet highly reliable feedthrough assemblies, preferably at low cost. Such miniaturized feedthroughs may, for example, be used in hybrid or electric cars, for example in electric compressors or e-compressors.
Since compressors e.g. in air-conditioning equipment and refrigeration units have motors inside, conductive particles generated by wear of bearings and other sliding parts gradually accumulate in the refrigerant. If these conductive particles adhere to the surface of the sealing element that insulates and seals the base body and the pin of the hermetic seal, the insulation resistance between base body and pin will gradually decrease, and in extreme cases there is a risk of a short circuit.
Generally, with respect to electrical feedthrough assemblies for e-compressors, it has to be taken into account that especially in the e-compressor application the housing part is exposed to temperature changes over a large interval of temperatures, temperature shocks and/or vibrations.
Electric compressors or e-compressors are widely used in environmentally friendly vehicles to support the operation of the air conditioning system. Further, e-compressors are present in air conditioners, refrigerators, other cooling systems etc. Electric and hybrid vehicles are equipped with battery powered electric compressors. The electric compressors must be hermetically sealed and function with their own motor inside. E-Compressor terminals or feedthrough assemblies are important components of electric compressors and must be designed and manufactured carefully for optimal performance. An e-compressor terminal enables the transfer of large amounts of energy from the battery to the air conditioning compressor, and at the same time must remain reliably gas-tight to prevent refrigerant leakage. Electric compressors have very high performance and durability requirements while also being subjected to harsh environmental conditions. These include high pressure, high humidity and vibration. Compressor terminals or feedthroughs must be able to withstand such adverse conditions without issue. Highly controlled and precise processes are necessary to provide long-term reliable gas-tightness. Moreover, the compressor terminals must deliver extremely high insulation resistance and high voltage capabilities to support future quick-charging technology developments. Leaking currents have to be avoided to prevent the operation efficiency of the electric compressor from decreasing. High current capabilities are also essential to enable upcoming 48 V electrical systems.
The risk of short circuit and high-voltage breakdown are known problems with electrical feedthrough assemblies and especially those used in e-compressors. Besides short circuits caused by conductive particles or wear accumulating in a liquid, a short circuit can occur in case e.g. a film of a conductive material such as water wets the metal parts of the housing, the base body and/or the pin, also called conductor. Such a water film wetting the metal parts as well as the insulating material can very easily occur in an e-compressor with an e-compressor terminal. This is due to the fact that the e-compressor has a very low temperature e.g. of lower e.g. 5 °C or even negative temperatures, whereas the ambient temperature e.g. in the summertime might be higher than 20 °C. In such a case, a water film can form due to condensation.
Another aspect is that the pin or the pins of a feedthrough assembly has/have to be connected to other electrical units, for example a motor or inverter for which special connectors (also called e.g. "connector terminals", "plugs") are used. Such connectors often require additional cylindrical connection elements with corresponding diameters around the pins in order to establish the connection. Secure and tight connection of the parts is often problematic.
To prevent such problems different measures are known in the art to increase a creepage distance or insulation distance between the pin and the base body and to provide connectability:

Electrical feedthrough assemblies with additional insulating sleeves around the pins made of polymer (plastic and/or rubber), moulded with or adhered to the assembly (e.g. US 2021/0344139 A1 , US 2023/0335941 A1 ). These cylindrical insulating sleeves can contribute to reduce the risk of short currents, especially in case of wet or humid surroundings, when a water layer and/or dirt layer or the like might deposit on the surface of the sealing element made of glass or glass ceramic material. However, such technical solutions require the manufacture of moulds to produce the polymer parts and additional work steps for their secure attachment. Differences in the thermal expansion behaviour of the different materials used in the feedthrough assembly can lead to stresses in the joint or adhesive connection and can lead to the polymer parts becoming detached so that the polymer parts can come loose and peel off if they are poorly attached. Further, air inclusions, bubbles or other weak points in the joint or adhesive connection between the feedthrough assembly and attached polymer parts can lead to failure of the insulation.
Electrical feedthrough assemblies with glass climbs formed due to surface tension and/or capillary forces of the insulating material, i.e. free formed protrusions of the insulating material of the sealing element, extending along the pins with decreasing diameter (e.g. US 2012/0018216 A , CN 211455988 U ). Such free-formed, arc shaped glass climbs are disadvantageous as they do not have a standardized form and require additional standardized cylindrical connection elements, e.g. attached rubber insulator, for providing the required insulation and dielectric strength and for establishing the electrical connection via a connector.
Electrical feedthrough assemblies with an additional insulating ceramic sleeve provided around the pin at a first side of the base body outside the through hole and connected to the sealing element which is holding the pin. The ceramic sleeve has a cylindrical outer shape and can be provided e.g. in the form of a circular hollow cylinder-shaped body or funnel-shaped formed body. The ceramic sleeve is placed around the pin and sealed or adhered to a surface of the sealing element. Such ceramic sleeve surrounds the pin and increases the creepage distance between the base body and the pin, however, there is a gap between the outer surface of the pin and the surrounding inner surface of the hollow cylinder-shaped sleeve associated with e.g. the risk that liquid and wear can penetrate into the gap. Such feedthrough assemblies are disclosed for example in US 5,493,073 ; US 2012/0228023 A ; JP2001-93596 , US 2014/375157 A . However, such known feedthrough assemblies comprise different kinds of insulating materials connected to one another having different thermal properties - especially thermal expansion properties. If e.g. thermal or compressive stress or mechanical force is applied to the connection between the sealing element and the ceramic sleeve, cracks can be formed in the connection region providing short circuit paths. In the worst case the ceramic sleeve can get lost. In order to provide an improved version having more mechanical stability JP 6403530 B discloses a feedthrough assembly wherein the ceramic sleeve protrudes into the sealing element, at least with a portion thereof, wherein a cavity is provided surrounding the pin on the junction surface of the ceramic sleeve, which can stop cracks in the ceramic sleeve at the cavity and prevents the formation of a linear and continuous short circuit path from the base body to the pin. The provision of a cavity in the bonding surface (sealing surface) may improve the reliability of the hermetically sealed terminal because a sufficient creepage distance can be maintained in the event of cracks. However, such a design is very complex to manufacture and thus expensive.
Electrical feedthrough assemblies with enamel sleeve placed around the pin and sealed or adhered to the sealing element ( JP6449552 B2 ). The enamelled sleeve of the hermetic sealed terminal comprises a metal base and a part or all the surface of this metal base covered with an insulating frit fired film. Although such enamelled sleeves can withstand higher shear forces than ceramic sleeves, for example, and have a smoother surface, the fastening is also complex here, and the enamelled sleeve has similar disadvantages like the ceramic sleeve described above.

None of the above-cited documents of the state of the art addresses the problem of easy to manufacture the feedthrough assemblies at the same time ensuring a perfect seal, a high creepage distance, high insulation and providing better connectability to connectors, like plugs and so on. Consequently, there is a need for improved electrical feedthrough assemblies that may be employed in applications where high precision and reliability are required such as in pressure sensors, e-compressors or electrical storage devices or like applications.

Object of invention

The object of the present invention is to provide an electrical feedthrough assembly with improved electrical insulation and an extended creepage distance that is easy to manufacture and at the same time enables simple connection to a connector, plug etc.

Description of invention

The object of the present invention is solved by the subject-matter of the independent claims. Preferred or special embodiments are disclosed in the dependent claims, the description and the figures of this application.
In a first aspect of the disclosure therefore relates to an electrical feedthrough assembly especially for the attachment to a housing, the assembly comprising a base body having a first side and a second side, the base body comprising at least one through hole. At least one pin is arranged within the at least one through hole that is electrically isolated from the base body and sealed in the through hole by a sealing portion made of an insulating material so that at least one feedthrough is formed in the base body. The sealing portion extends between the pin and the base body and thus surrounds the pin. In order to increase a creepage distance between the base body and the pin an insulating sleeve portion is provided around the pin at the first side of the base body outside the through hole wherein the insulating sleeve portion has a cylindrical part having a length that is at least 50% of the length of the insulating sleeve portion wherein length is measured in direction of a longitudinal axis of the pin. The electrical feed through assembly is characterized in that the sealing portion and the insulating sleeve portion are present in one piece in the form of an integral insulating element made of insulating material wherein the insulating material comprises glass or consists of glass or is made of glass, and in that the insulating sleeve portion is sealed to the pin.
Preferably the electrical feedthrough assembly is configured for attachment to a housing for an e-compressor, an electrical storage device, a pressure sensor or the like.
The provision of an integral insulating element has a lot of advantages as describe below.
"Present in one piece" means that the insulating sleeve portion is made integral with the sealing portion, forming the integral insulating element. Thus, the insulating sleeve portion protruding beyond the base body, i.e. the section providing the extension of the creepage distance, is formed directly during the process of sealing pin and base body together in order to generate the feedthrough assembly. It is not necessary to place a separate insulating tube, sleeve or cylinder around the pin during or after forming the feedthrough assembly and to attach it e.g. via an adhesive. This measure saves time and costs during assembly because less individual parts have to be assembled. In addition, there is also a much lower risk that the insulating sleeve portion coming loose or breaking off and being lost. For providing the integral insulating element, the preform of the insulating material may be shaped accordingly and a corresponding suitable mould may be used during sealing the components of the feedthrough assembly which is explained below.
Further, the insulating material in the electrical feedthrough assembly of the disclosure comprises a glass or consists of glass or is made of glass, which is advantageous as the glass material, during sealing, melts and flows, which means that a good physical and/or chemical contact between the surface of the glass and the pin and, of course between the surface of the glass and the base body may be obtained rather easily. A tight glass-to-metal-feedthrough is provided.
According to the invention the part of the insulating material that forms the insulating sleeve portion is sealed to the pin, i.e. a surface of the pin, during assembling the components of the feedthrough. I.e, the insulating material contacts and directly covers the surface of the pin in a contact area between the pin and the insulating sleeve portion. In contrast to a ceramic or enamelled sleeve having a material being different from the sealing portion and added to the assembly during or after forming the feedthrough, there is no gap between the insulating sleeve portion and the surface of the pin and thus an improved electrical insulation and tight seal are provided. In addition, the mechanical strength is increased, as the insulating sleeve portion is less likely to break under the effect of mechanical force.
The insulating sleeve portion protrudes beyond the base body. The insulating sleeve portion made integral with the sealing portion has a cylindrical part having a length that is at least 50% of the length of the insulating sleeve portion wherein the length is measured in direction of a longitudinal axis of the pin. The cylindrical part protrudes beyond the base body. This is beneficial for providing an increased creepage distance and sufficient contact surface for a connector, plug and so on. Preferably the length of the cylindrical part is at least 70% or at least 80% or at least 90% of the length of the insulating sleeve portion. In an area near an edge of the through hole and/or an area near an end face of the insulating sleeve portion facing away from the base body the outer shape of the insulating sleeve portion may deviate from the cylinder shape, e.g. there can be a curved surface section and/or a chamfered surface section.
Preferably the cylindrical part of the insulating sleeve portion may have a circular cylinder shape. However, general cylinder shapes with other end face shapes are also conceivable and can be advantageous. For example, oval shapes or polygonal shapes, preferably a regular polygonal shape, with rounded corners are conceivable.
The invention reduces the number of individual parts of a feedthrough assembly and provides a technically simple solution that leads to a faster, more cost-effective production and safer and more robust design. In addition, the feedthrough assembly has improved electric insulation and sealing properties. Further, because of the cylindrical part of the insulating sleeve portion around the pin a connector for connection with an electric device, motor etc. can be fitted onto the pin very easily.
Base body, integral insulating element and pin form a glass-metal-feedthrough by which the through hole of the base body is closed. Preferably, the formed feedthrough is hermetically sealed. Hermetic tightness is in particular understood to mean that the leakage rate of helium at a pressure differential of 1 bar is preferably < 1·10^-7 mbar ls^-1, more preferably < 1·10^-8 mbar ls^-1, and most preferably < 1·10^-9 mbar ls^-1.
Preferably the insulating sleeve portion and the sealing portion are made of the same insulating material. Thus, there is no material boundary between those portions which could be a starting point for cracks e.g. caused by thermically or mechanically induced stress. As a consequence, the feedthrough assembly is more reliable. Alternatively, the insulating material of the sealing portion and the insulating material of the insulating sleeve portion may comprise, consist of or be made of different glasses wherein preferably the glasses match each other, for example fuse with each other and/or have a similar thermal expansion behaviour.
Preferably the first side of the base body with arranged insulating sleeve portion is the side facing the motor or driving system in the e-compressor - referred to as motor side - when the feedthrough assembly is attached to a housing. The insulating material of the insulating sleeve portion increases the creepage distance between the base body and the pin by increasing the insulation distance therebetween. This helps to prevent insulation degradation and electrical shorts caused, for example, by fine metal powders (such as wear debris or chips from a drive system inside a compressor) sticking between the base body and the pin.
Preferably the first side of the base body with arranged insulating sleeve portion is the side facing the inverter in the e-compressor - referred to as inverter side - when the feedthrough assembly is attached to a housing. The insulating sleeve portion increases the creepage distance between the base body and the pin. As the insulating sleeve portion is bonded to the pin surface, no moisture (e.g. condensed water) can penetrate between that portion and the pin.
In an especially advantageous further development, the electrical feedthrough assembly has at least one insulating sleeve portion at the first side of the base body and at least one further insulating sleeve portion at the second side of the bases body, described further below.
Preferably an outer surface of the cylindrical part of the insulating sleeve portion is predominantly a moulded surface. "Moulded surface" means that the surface has been formed in contact to moulds during sealing the feedthrough components, i.e. the outer surface of the cylindrical part is not a fire-polished surface unlike the surface of a known free formed, arc shaped protrusion of the insulating material extending along the pin (also called "glass climb" or "glass meniscus"). A moulded surface may easily be distinguished from a fire-polished surface by the person skilled in the art, as such a moulded surface is characterized by not being glossy. A moulded outer surface, i.e. rougher outer surface, can be beneficial in order to provide a strong mechanical hold for a connector put around the pin and being in contact with the insulating sleeve portion. Advantageously a surface of an end face of the insulating sleeve portion is also a predominantly moulded surface. Preferably a moulded surface has a surface roughness Ra (arithmetic average surface roughness) of more than 0.4 µm, preferably more than 0.6 µm, preferably more than 0.8 µm, preferably more than 1.0 µm. An advantageous upper limit for Ra can be less than 3.2 µm or less than 1.6 µm. The surface roughness Ra was determined tactilely here using a profilometer. Ra is preferably determined in accordance with DIN EN ISO 4287:1984.
The length of the insulating sleeve portion depends on the size and overall design of the electrical feedthrough assembly. Preferably the length may be in the range of from 1.0 mm to 20 mm, preferably from 1.5 mm to 15 mm, preferably from 1.5 mm to 10 mm.
Preferably the feedthrough assembly comprises at least one of the following features:

an outer diameter of the cylindrical part of the insulating sleeve portion is essentially as great as a diameter of the through hole of the base body at the first side,
an outer diameter of the cylindrical part of the insulating sleeve portion is smaller than a diameter of the through hole of the base body at the first side.

In other words, depending on the design and the arrangement of the feedthrough assembly in the later electrical device the relation between an outer diameter of the cylindrical part of the insulating sleeve portion and a diameter of the through hole at the first side of the base body - where the insulating sleeve portion is arranged - can be different:
In an advantageous variant A, the outer diameter of the cylindrical part may be essentially as great as a diameter of the through hole of the base body at the first side. This can be beneficial because the preform for integrally forming the sealing portion and the insulating sleeve portion can be less complex to manufacture. Further, this can be beneficial for a feedthrough assembly wherein the pin is fixed inside the through hole via an advantageous compression seal. That is, the coefficient of thermal expansion of the insulating material is smaller than the coefficient of thermal expansion of the base body so that a compression seal feedthrough results. However, an adapted seal wherein the coefficients of thermal expansion of the insulating material and of the base body are matched to one another may also be possible and advantageous.
In an advantageous variant B, the outer diameter of the cylindrical part may be smaller than a diameter of the through hole of the base body at the first side. This can be beneficial for a feedthrough assembly wherein the pin is fixed inside the through hole via a compression seal. That is, the coefficient of thermal expansion of the insulating material is smaller than the coefficient of thermal expansion of the base body so that compression seal feedthrough results. In a compression seal the base body provides compression to the sealing portion with inserted pin. In the area of the edge of the through hole a decrease of compression may induce stress in the insulating material in the transition zone between sealing portion located inside the through hole and the insulating sleeve portion located outside the through hole which can lead to cracks in the glass. This can be avoided by such an arrangement, because less compression stress is exerted on the transition zone of the insulating sleeve portion by the base body reducing the risk of generating cracks in the insulating material. However, an adapted seal wherein the coefficients of thermal expansion of the insulating material and of the base body are matched to one another may also be possible and advantageous.
In case the feedthrough assembly has more than one feedthrough (which is described in detail below), the cylindrical parts of the insulating sleeve portions at the first side may preferably be formed the same way, i.e. all insulating sleeve portions at the first side of the base body are formed corresponding to variant A or variant B. In other words, the feedthrough assembly can comprise more than one feedthrough wherein the insulating sleeve portions thereof may be formed either corresponding to variant A or corresponding to variant B. This is beneficial for the overall design and preferable in terms of production. Preferably the cylindrical parts of the insulating sleeve portions at the first side may be formed identically. However, it is also conceivable and may be advantageous, if there is at least one insulating sleeve portions at the first side of the base body formed corresponding to variant A and at least one insulating sleeve portions at the first side of the base body formed corresponding to variant B. It may also be possible and can be advantageous, if the feedthrough assembly comprise at least one feedthrough having variant A and/or B and at least one feedthrough without insulating sleeve portion at the first side of the base body, in case an increased creepage distance is not required for the concerned pin.
In an advantageous variant C, the outer diameter of the cylindrical part may be greater than a diameter of the through hole of the base body at the first side. Thus, the insulating sleeve portion may cover the edge of the through hole in the base body. In case the feedthrough assembly has more than one feedthrough, variant C can be realized alone or in combination with variant A and/or variant B and/or with a feedthrough without insulating sleeve portion described above.
Below, advantageous features A to C of the integral insulating element at the second side of the base body are described. In an advantageous embodiment, the feedthrough assembly comprises at least one of features A to C. If the feedthrough assembly has more than one feedthrough (which is described in detail below), the integral insulating elements at the second side of the base body may preferably be formed identically, i.e. all integral insulating elements at the second side of the base body have feature A or feature B or feature C. This is beneficial for the overall design and preferable in terms of production. However, it is also possible and can be advantageous, if there is at the second side of the base body at least one integral insulating element having feature A and/or at least one integral insulating element having feature B and/or at least one integral insulating element having feature C. This means that at least two of features A to C may occur at the second side in any possible combination.
Feature A: Preferably an end face of the sealing portion of the integral insulating element at the second side of the base body is essentially flush with the surface of the base body ("flush arrangement" of the sealing portion) or the second side of the base body may protrude above the end face of the sealing portion ("recessed arrangement" of the sealing portion). This enables a flat design on the second side of the base body. It is conceivable that a separate insulating sleeve, e.g. made of ceramic, may be placed around the pin and be connected to the flush or recessed sealing portion.
Feature B: Preferably - at the second side of the base body - the sealing portion of the integral insulating element comprises an arc shaped extending portion of the sealing material such that the sealing portion extends beyond the second side of the base body along the pin and completely surrounds it. The extending portion is in contact with the pin. The arc shaped extending portion has a diameter that decreases, preferably continuously decreases, from the second side of the base body along the pin, thereby forming an arc, i.e. the arc shaped extending portion has a curved outer surface. In other words, the insulating sleeve portion arranged at the first side of the base body, the sealing portion arranged within the through hole and the arc shaped extending portion of the sealing material arranged at the second side of the base body are present in one piece in the form of the integral insulating element.
Such an embodiment is very advantageous, as the creepage distance, i.e. insulation distance, between base body and pin provided at the second side of the base body is increased, too. An arc shaped extending portion of the sealing portion (also called "glass climb" or "glass meniscus") is free formed without contacting a mould during sealing the components of the feedthrough assembly together. The creepage distance is increased according to this embodiment by the insulating material itself, for example by the insulating material being made of glass, being melted during manufacture and thus forming, preferably by surface tension and/or capillary forces, an extending portion along the pin. For providing an extending portion, the preform of the insulating material may be shaped accordingly so that the preform comprises extending parts. Preferably, the surface of the extending portion has a fire-polished surface, which further improves the chemical stability of the feedthrough assembly.
The fire-polished surface preferably has a surface roughness Ra (arithmetic average surface roughness) of at most 0.4 µm, preferably at most 0.3 µm, preferably at most 0.2 µm or at most 0.1 µm. The method of measuring Ra has been cited above.
In the sense of the disclosure, the expression" the extending portion completely surrounds the pin" refers to the extending portion forming a cone structure around the circumference of the pin, without any cuts or openings in the extending portion along the circumference of the pin and, hence, the extending portion. However, the extending portion does not cover the tip of the pin as the pin has to be electrically connected.
Feature C: Preferably the feedthrough assembly comprises a further insulating sleeve portion provided around the pin at the second side of the base body outside the through hole and sealed to the pin. The further insulating sleeve portion protrudes beyond the base body and has a further cylindrical part having a length that is at least 50% of the length of the further insulating sleeve portion (measured in direction of a longitudinal axis of the pin). Thus, the further cylindrical part protrudes beyond the base body. In this embodiment the further insulating sleeve portion, the sealing portion and the insulating sleeve portion are present in one piece in the form of an integral insulating element. Such an embodiment is very advantageous, as the creepage distance, i.e. insulation distance, between base body and pin provided at the second side of the base body is increased, too. In addition, because of the further cylindrical part a better connectability of the pin with a connector is provided at the second side of the base body compared to an embodiment with arc shaped extending portion.
Preferably the further insulating sleeve portion is made of the same insulating material as the sealing portion and/or the sealing portion. In a preferred further development, the further insulating sleeve portion, the insulating sleeve portion and the sealing portion are made of the same insulating material. This is advantageous because there is no material boundary between those portions which could be a starting point for cracks e.g. caused by thermically or mechanically induced stress. As a consequence, the feedthrough assembly is more reliable.
Preferably the feedthrough assembly with further insulating sleeve portion comprises at least one of the following features:

an outer diameter of the further cylindrical part of the further insulating sleeve portion is essentially as great as a diameter of the through hole of the base body at the second side,
an outer diameter of the further cylindrical part of the further insulating sleeve portion is smaller than a diameter of the through hole of the base body at the second side.

If the feedthrough assembly has more than one feedthrough (which is described in detail below), the further cylindrical parts of the further insulating sleeve portions at the second side may preferably be formed identically or differently with respect to the insulating sleeve portions at the first side of the base body which realization and possible combinations have been described in detail above. - Furthermore, the explanations and advantageous further developments given above in connection with the description of the `insulating sleeve portion' at the first side of the base body also apply accordingly to the 'further insulating sleeve portion' provided at the second side of the base body. Reference is made to this in order to avoid repetition.
In terms of dimensions - especially outer diameter, length of sleeve portion, length of cylindrical part etc. - the further insulating sleeve portion at the second side of the base body can be identical or different to the insulating sleeve portion(s) at the first side of the base body. In the case of a different design, each insulating sleeve portion can be adapted to the respective insulation requirements and the type of connection.
Advantageously, at least one through hole of the feedthrough assembly is configured as a stepped through hole having at least one surface part adjacent to a side of the base body and a middle part, wherein a diameter of the surface part is larger than a diameter of the middle part, and wherein the insulating material of the integral insulating element, preferably of the sealing portion, is present in both the middle part and in the at least one surface part of the through hole.
In the sense of the disclosure "middle part" is that part of the through hole that will be located in a middle section of the stepped through hole, if the stepped through hole has surface parts with larger diameters on both sides. Here, the heights of the surface parts are preferably smaller than half the thickness of the base body. If the stepped through hole only has the surface part with larger diameter only on one side of the base body, the "middle part" will extend from the middle section of the through hole up to the opposite other side of the base body. Here, the height of the surface part is preferably as great as or smaller than half the thickness of the base body. It is conceivable that the height of the surface part is even higher than half the thickness of the base body.
In the sense of the disclosure, a stepped through hole is understood to refer to a through hole that is configured so that it comprises at least two parts that have different diameters. In the scope of the present disclosure, the part of the base body that may provide compression in order to tightly seal the feedthrough has been diminished in order to provide for a larger creepage distance provided by the surface part of the through hole. By doing so, not only the creepage distance is increased, but - in the case of a compression feedthrough - it is still possible to achieve a high enough compression for the feedthrough. Thus, according to embodiments it is also possible to provide for hermetic feedthrough assemblies in a miniaturized design that at the same time have a high creepage distance and are thus suited for high voltage applications.
Preferably the surface part with enlarged diameter of the through hole may be arranged at the first side of the base body, i.e. that side where the insulating sleeve portion of the integral insulating element is present. A combination of a stepped through hole having the surface part with enlarged diameter in combination with an insulating sleeve portion at the same side of the base body leads to a very long creepage distance between the pin and the base body.
Preferably the surface part with enlarged diameter of the through hole may be arranged at the second side of the base body, which will also increase the creepage distance between the pin and the base body at that side, if the end face of the sealing portion of the integral insulating element is e.g. essentially flush with the surface of the base body. Advantageously, the creepage distance at the second side will be even more increased, if there is additionally the arc shaped extending portion of the sealing material (also called glass climb or meniscus) or the further insulating sleeve portion on that side. In other words, a combination of the surface part with enlarged diameter of the through hole and another feature for increasing the creepage distance may be advantageous.
The arc shaped extending portion, the insulating sleeve portion and the further insulating sleeve portion and their advantageous features have already been described in detail above. Reference is made to this in order to avoid repetition. These explanations also apply to embodiments of the feedthrough assembly having the stepped through hole. However, as far as the relationship between the outer diameter of the (further) cylindrical part of the (further) insulating sleeve portion and the diameter of the through hole at the first side or the second side of the base body is concerned, the relevant diameter of the through hole at the first side or at the second side may be the diameter of the surface part or of the middle part of the stepped through hole.
Preferably the at least one through hole may be formed as a stepped through hole so that the through hole comprises surface parts formed at both sides of the base body with two diameters being larger than the diameter of the middle part of through hole. In other words, in this case the through hole is configured as a stepped through hole at the first side and at the second side of the base body. Preferably, the surface parts having the enlarged diameters may be formed identical on both sides of the base body. However, the diameters of the enlarged surface parts and/or the heights of the surface parts can also be different on both sides, depending on the overall design and needs of the feedthrough assembly. Shaping the through hole so that it is formed as s stepped through hole on both sides of the base body, as explained above, is advantageous as in this way, the creepage distance is increased on both sides of the assembly. Of course, the stepped through hole with surface parts on both sides can be combined with the flush arrangement of the integral insulating element, with the arc shaped extending portion and/or with the further insulating sleeve portion as described above.
Generally, without being restricted to any embodiment of the disclosure, the middle part of the stepped through hole holds the sealing portion and - especially in the case of a compression feedthrough or seal - serves for providing a pressure on the sealing portion helping to provide a tight seal and fixture of the pin whereas the surface part(s) of the stepped through hole having the larger diameter, i.e. having the enlarged diameter, also hold(s) the sealing portion and enlarges the creepage distance. The sealing material is present in both the middle part and the surface part(s) of the through hole. In other words, in the case of a stepped through hole, the middle part and the surface part(s) of the through hole define the sealing portion.
Generally, without being limited to any of the special embodiments described within the present disclosure, the at least one through hole is formed having a circular cross section, of course within the limits of standard manufacture tolerances. That is, in the case of a "simple through hole", the through hole has just one circular cross section that is characterized by having a diameter. In the case of a stepped through hole, the middle part and the surface part(s) of the through hole have circular cross sections that are characterized by each having a diameter.
If the feedthrough assembly has more than one feedthrough (which is described in detail below), the corresponding through holes can be formed identical, i.e. either simple through holes (i.e. through holes having just one diameter) or stepped through holes, preferably identically stepped through holes. This is beneficial for the overall design and preferable in terms of production. However, it may also be possible and can be advantageous, if the though holes are different, e.g. a combination of at least one simple though hole and at least one stepped through hole or a combination of differently arranged and/or differently shaped stepped through holes etc.
Generally, without being restricted to any further development of the disclosure, in case the electrical feedthrough assembly may comprise more than one so-called "stepped through hole" according to any variation of the through hole and/or the electrical feedthrough assembly as disclosed, these through holes may preferably be formed identically. However, in other advantageous variations, the through holes may be formed differently with respect to each other and/or at least one through hole may have a surface part at the first side that is different from the surface part at the second side of the base body and so on.
Advantageously the pin and/or the base body may have an oxidized surface or a bare surface. An oxidized surface can be advantageous for providing a strong chemical bond to the insulating material during sealing the pin in the base body forming the feedthrough. However, for providing effective corrosion protection of the pin and/or base body a subsequent Ni plating after bonding / sealing may be necessary wherein an oxidized surface layer has to be removed by an acid treatment prior to subsequent Ni plating which is time consuming and may damage the feedthrough assembly.
Preferably the pin comprises a Ni-plating in an entire contact area with the insulating material of the integral insulating element. Preferably the base body comprises a Ni-plating in an entire contact area with the insulating material of the integral insulating element. It can be particularly advantageous if both the pin and the base body comprise a Ni-plating in the respective entire contact area with the insulating material of the integral insulating element.
Based on the feature that the Ni-plating is present in the entire contact area(s) with the insulating material, it can be clearly determined that the pin and/or the base body was Ni-plated prior to joining the components to form the feedthrough assembly.
Such arrangements have a lot of advantages. For example, it is not necessary any more to Ni-plate the electrical feedthrough assembly after its assembly, as the pin and/or the base body has already been Ni-plated prior to assembly, thus having the required highly conductive, corrosion protected surface necessary for the application. This possibility of using a pin that has been Ni-plated prior to assembly is particularly advantageous in embodiments in which the base body is also Ni-plated prior to assembly and/or the assembly comprises several pins that have all been Ni-plated prior to assembly, that is, all metals parts that need to comprise this highly conductive, corrosion protected surface are, like the at least one pin, provided prior to assembly as already Ni-plated part(s).
In the sense of the disclosure, a Ni-plating is understood to refer to a coating (or plating) that is preferably obtained in a wet-chemical process, preferably in an electrochemical plating method that is known in the state of the art. Though usually only referred to as "Ni-plating" or "Nickel plating", the coating may comprise other elements than Nickel, so that a Nickel alloy results. For example, the coating may comprise, in addition to Nickel, elements such as Cobalt, or Zinc, or Iron. In the sense of the disclosure, "Ni-plating" and "Ni-coating" may be used interchangeably. Also, the expression "the pin comprises a Ni-plating" may be used interchangeably with the expression "the pin is Ni-plated", both expressions referring to the fact that the pin comprises a layer, preferably an outermost layer, that is made of a so-called "Ni-plating", that is, a Ni-coating within the sense of the disclosure and explained in detail above.
Advantageously, the Ni-plating may be essentially Phosphor-free, that is, comprise Phosphor only in an amount of unavoidable chemical traces such as not more than 500 ppm by weight. In other words, according to a preferred embodiment, the Ni-coating may be applied in a galvanic process in which Phosphor is not a mandatory component.
The melting temperature of the Ni-plating may advantageously be higher than the sealing temperature applied for sealing the pin and the insulating material into the base body. This means that the Ni-plating does not melt during the sealing process.
Preferably the film thickness of the Ni-plating is between at least 1 µm and at most 15 µm, preferably between at least 2 µm and at most 8 µm. This thickness is sufficient for providing effective corrosion protection of the Ni plated metal parts. In addition, the Ni plated pin and/or base body can be better electrical contacted in the later application. A subsequent Ni plating after bonding / sealing is not necessary.
Preferably a surface roughness R_z, i.e. the maximum peak-to-valley height measured according to DIN EN ISO 4287:1984, of the pin and/or the Ni-plating is less than 15.0 µm, preferably less than 12.0 µm, preferably less than 10.0 µm, preferably less than 8.0 µm, preferably less than 7.0 µm, preferably less than 6.0 µm. An advantageous lower limit for the surface roughness R_z of the pin and/or the Ni-plating can be 1.0 µm. This is very advantageous, as the given roughness is a roughness easily obtained in standard manufacturing processes of pins. The surface roughness of the pin translates into the surface roughness of the coating, that is, the Ni-plating in this case. However, in the state of the art, in order to ensure a tight connection between the Ni-plating and the insulating material that comprises glass or consists of glass or is made of glass, the pin very often had to be surface treated, for example, oxidized and/or roughened in order to provide for a tight connection and, thus tight seal.
Preferably the whole surface of the pin and/or of the base body is Ni-plated, that is, the whole surface of the pin and/or of the base body comprises a Ni-plating. This means, in particular, that the Ni-plating is present in that parts of the above cited component(s) that are not in contact with the insulating material of the integral insulating element as well as in that parts of the above cited component(s) that are in contact with the insulating material.
While the electrical feedthrough assembly of the disclosure in general may comprise only one feedthrough having only one through hole and, consequently, only one pin, the electrical feedthrough assembly of the disclosure is very well suited for assemblies comprising at least two feedthroughs having two pins, for example, for assemblies comprising three feedthroughs wherein the three pins and, consequently, a number of through holes are preferably arranged in a line which can be an arc-shaped line or a straight line. Alternatively, pins may also be arranged in a circular, triangular or rectangular shape.
In an advantageous further development, the feedthrough assembly has more than one pin and thus feedthrough, wherein each feedthrough comprises the insulating sleeve portion of the integral insulating element at the first side of the base body, optionally having further advantageous features described above. This is advantageous in terms of overall assembly design and manufacture. Preferably, the design and arrangement of the integral insulating elements of the feedthroughs at the second side of the base body may be the same, i.e. may correspond to each other, optionally having further advantageous features described above. This is advantageous in terms of overall assembly design and manufacture. Preferably the integral insulating element of the feedthroughs may be formed identically at the first side and/or at the second side of the base body, but do not have to be.
In such an arrangement at least one through hole or all through holes may be designed as stepped through holes with one or two surface parts as described above. If there are two or more stepped through holes, they may preferably be designed and arranged identically at the first side of the base body and/or the second side of the base body, but do not have to be.
Advantageously, all through holes of the electrical feedthrough assembly may be configured as stepped through holes each having at least one surface part adjacent to a side of the base body and a middle part, wherein the diameter of the middle part is smaller than the diameter of the surface part wherein preferably all surface parts are formed at the same side of the base body. This is advantageous as in this case, the creepage distance is enlarged for all pins of the electrical feedthrough assembly.
Advantageously, all through holes may be formed as stepped through holes comprising surface parts formed on both sides of the base body with diameters being larger than the diameter of the middle part of the respective through hole, wherein preferably the surface parts are each formed identically at both sides.
In an advantageous further development the feedthrough assembly comprises at least two feedthroughs and pins wherein a distance between the at least two pins, determined as a distance between a center point of one pin to a center point of the other pin is in the range of at least 1.2 times and at most 1.6 times of the diameter of the at least one through hole or - in the case of a stepped through hole - of at least 1.2 times and at most 1.6 times of the diameter of the the middle part of the at least one through hole. If the feedthrough assembly has three feedthroughs and pins the pitch is preferably the same between all pins, i.e. adjacent pins, wherein the pins are preferably arranged in a straight line or an arc shaped line.
Such an arrangement has a lot of advantages. The distance between the center points of the at least two pins is at least 1.2 times, preferably at least 1.3 times, and at most 1.6 times, preferably at most 1.5 times, and for example at 1.4 times, of the respective diameter given above. This means that the at least two pins are spaced very closely to each other. This enables a very compact overall design of the electrical feedthrough assembly. However, the drawback of such a very close arrangement of the pins is that the feedthrough may not be suited for applications with a high voltage, as in such a compact design, the creepage distance that is provided by the insulating material may be too small. This, however, is addressed in the electrical feedthrough assembly of the disclosure by providing the integral insulating element having the insulating sleeve portion at the first side of the base body and optionally having a flush arrangement of the sealing portion or an arc shaped extending portion or a further insulating sleeve portion at the second side of the base body. Shaping at least one through hole so that preferably at least one surface part is formed that has a larger diameter than the diameter in a middle part thereof, i.e. providing a stepped through hole, also increases the creepage distance. This helps to prevent insulation degradation and electrical shorts caused, for example, by fine metal powders (such as wear debris or chips from a drive system inside a compressor) sticking between the base body and the pin.
If the distance between the center points of the at least two pins is less than 1.2 times of the respective diameter, the base body - if present the middle part of the stepped through hole - may not be able to provide sufficient pressure on the insulating material needed in a compression feedthrough for providing a tight seal. Plastic deformation may occur instead. If the distance between the center points of the at least two pins is more than 1.6 times of the respective diameter, the overall design of the feedthrough assembly gets too large.
Advantageously the base body may have a thickness of at least 2 mm and/or at most 6 mm, and/or, in case the through hole is formed as a stepped through hole, the middle part may have a height of at least 1 mm and/or at most 4 mm. In that way, the base body can exert sufficient pressure on the insulating material, which ensures a tight seal, while at the same time, a sufficient enlargement of the creepage distance is provided for high voltage and/or high power applications. Preferably, the thickness of the base body may be at least 2.5 mm, more preferably at least 3 mm. Further, the thickness of the base body preferably may be at most 5.5 mm, more preferably at most 5 mm. Furthermore, preferably, if present, the middle part may have a height of at least 1.5 mm, preferably at least 2 mm, and further preferably, the middle part may have a height of at most 3.5 mm, preferably at most 3 mm.
The height of the surface part depends on the overall design of the feedthrough assembly and can preferably be as great as or smaller than half the thickness of the base body. Preferably the height of the at least one surface part is at least 0.2 mm, preferably at least 0.3 mm or at least 0.5 mm. A certain minimum height is advantageous, as otherwise there is a risk that the glass in the surface part will flake off. In some variants - especially with a through hole having surface parts on both sides of the base body - an advantageous upper limit for the height of the surface part may be 1.0 mm or 0.7 mm. An advantageous range for the height of the surface part can be 0.2 mm to 1.0 mm or 0.3 mm to 0.7 mm.
Preferably, the material of the base body is a metal. Preferably - in connection with a compression seal -, the base body comprises steel, preferably stainless steel. In an advantageous embodiment, the material of the base body comprises structural steel, preferably microalloyed steel, most preferred structural steel in form of microalloyed steel. Microalloyed steel is a type of alloy steel that contains small amounts of alloying elements (0.05 to 0.15 %), including niobium, vanadium, titanium, molybdenum, zirconium, boron and rare-earth metals. They are used to refine the grain microstructure or facilitate precipitation hardening. The yield strength of microalloyed steel is between 275 and 750 MPa without heat treatment. Weldability is good and can even be improved by reducing carbon content while maintaining strength. Fatigue life and wear resistance are superior to similar heat-treated steels. Cold-worked microalloyed steels do not require as much cold working to achieve the same strength as other carbon steel; this also leads to greater ductility. By using microalloyed steel as material, a high bending stiffness and strength could be provided.
Preferably, the material of the pin is metal. Preferably - in connection with a compression seal -, the pin comprises or consists of stainless steel or a Ni-Fe-material or a Fe-Cr material or the pin comprises a central core made of copper surrounded by stainless steel or surrounded by a Ni-Fe-material.
In connection with a matched sealing (as explained below) the base body and the pin may comprise a Ni-Fe-Co alloy.
Preferably, the insulating material has a coefficient of thermal expansion, CTE (or α), between 8 * 10^-6/K and 12 * 10^-6/K, especially in connection with a compression sealing. For example, the insulating material can be an alkali silicate glass comprising CaO having a CTE in the range of 9 to 10 * 10^-6/K. In the context of the present disclosure, the expansion coefficient is specified as the coefficient of linear thermal expansion. If the specification relates to the coefficient of linear thermal expansion of a glass, this is the nominal coefficient of mean linear thermal expansion according to ISO 7991, especially ISO 7991:1987-12, which is determined in a static measurement (using a push rod dilatometer). The coefficient of linear thermal expansion of the glass is determined dilatometrically. Generally, the values are determined in the temperature range from 20°C to 300°C, if not stated otherwise.
In connection with a matched sealing, the coefficient of thermal expansion, CTE (or α) may be between 3 * 10^-6/K and 10 * 10^-6/K, for example 5 * 10^-6/K. For example, the insulating material can be a borosilicate glass.
In the sense of the disclosure, a glass is understood as an inorganic material that is obtained in a melting process and that is, after melting, an amorphous material. In the sense of the disclosure, the glass may be completely amorphous material, or may be a crystallizable or an at least partially crystallized glass that may sometimes also be denoted a so-called "glass ceramic".
Preferably the material of the base body and the insulating material are selected in such a way that the coefficient of thermal expansion (CTE) of the insulating material is smaller than the coefficient of thermal expansion (CTE) of the base body so that a compression seal feedthrough is provided.
In the sense of the disclosure, a compression seal is understood to refer to an electrical feedthrough assembly in which the CTEs of the respective component, that is, the metal parts, such as the base body and the at least one pin of the electrical feedthrough assembly, and the insulating material, are selected so that the base body exerts a compression upon the insulating material, thereby sealing the feedthrough. In order to obtain such a compression seal especially a glass-to-metal-seal, the thermal expansion coefficient (CTE, as explained further above) of the base body here is selected so as to be larger than the thermal expansion coefficient (CTE) of the insulating material such that, after a thermal treatment in which the insulating material melts and is glazed in the through hole, during cooling thermal contraction of the base body is stronger than in the insulating material. As a result, compression forces are permanently exerted by the base body on the insulating material. These compressive forces preload the insulating material and ensure a particularly durable seal.
In the case of a compression glass-to-metal seal, a difference between the thermal expansion coefficient (CTE, as explained further above) of the base body and the thermal expansion coefficient (CTE) of the insulating material is preferably at least 2 * 10^-6/K and more preferably the difference is at least 5 * 10^-6/K. In an advantageous embodiment the thermal expansion coefficient (CTE) of the base body is preferably selected to be at least 5%, in particular at least 10%, preferably at least 20%, and for some variants preferably at least 50% greater than the thermal expansion coefficient of the insulating material. A coefficient of thermal expansion of the pin material is preferably chosen to be about equal to or less than the coefficient of thermal expansion of the insulation material. Two coefficients of thermal expansion are considered to be about equal if the difference is less than 2 * 10^-6/K.
In an embodiment as an alternative to a compression seal feedthrough, the coefficient of thermal expansion of the base body and the coefficient of thermal expansion of the insulating material can be adapted to each other (also called "matched seal(ing)"). It is preferable if the difference between the coefficients of thermal expansion is less than 5%. In particular, an adapted feedthrough is understood to mean that the coefficients of thermal expansion substantially differ by a maximum of 1 * 10^-6 1/K, in particular are substantially the same.
As far as values for the coefficient of thermal expansion are mentioned above, these refer to the linear thermal coefficient of expansion α in the temperature interval 20-300°C usually given in connection with glass-metal feedthroughs.
According to an embodiment, the insulating material and the base body and/or the pin may form a substance-to-substance bond, which results in a very tight seal that may even be a hermetic seal. However, according to an embodiment, it is also possible that a form-lock join is formed that may also be a hermetic seal. In both cases, it is preferred for the sealing process during manufacture that the insulating material is provided as a preform that is shaped according to the form of the through hole and the requirements of the later integral insulating element. The final shape of the integral insulating element and its insulating sleeve portion (and optionally its further insulating sleeve portion) is also determined by corresponding moulds during sealing the components of the feedthrough assembly together.
Preferably, the tightness of the seal of the feedthrough will be even more increased, if the insulating material and the metal of the base body are selected in such a way that they form a compression seal feedthrough, that is, the coefficient of thermal expansion of the insulating material is smaller than the coefficient of thermal expansion of the base body.
According to a further aspect of the invention a process for manufacture of an electrical feedthrough assembly, preferably an electrical feedthrough assembly according to any embodiment of the disclosure, is provided comprising the steps:

providing a base body that comprises a through hole
providing a pin,
providing a shaped preform of the insulating material comprising or consisting of a glass,
placing the preform within the through hole of the base body, inserting the pin into the through hole of the preform or inserting the pin into the through hole of the preform, placing the preform with inserted pin within the through hole of the base body,
arranging the assembly in a mould, wherein the mould comprises a section for forming a cylindrical part of the later insulating sleeve portion,
heating base body, preform and pin so that the glass melts and contacts and/or wets the surface of the through hole of the base body and the surface of the pin and the surface of the mould so that the sealing portion and the insulating sleeve portion and optionally the further insulating sleeve portion are generated in one piece forming an integral insulating element, wherein the insulating sleeve portion is sealed to the pin and optionally the further insulating sleeve portion is sealed to the pin.

If the feedthrough assembly shall also have a further insulating sleeve portion at the second side of the base body another shaped mould may be necessary at the second side.
According to the disclosure, the electrical feedthrough assembly comprises glass as insulating material. The insulating material comprises glass or consists of glass or is made of glass Such an embodiment is very advantageous. For example, during manufacture of the assembly, the insulating material may be provided in the form of a preform that may, for example, comprise or consist of a glass powder, for example in the form of a pellet of glass powder that may even be presintered in order to provide a sufficient mechanical stability for handling during manufacture.
The preform of the later integral insulating element can be made in one piece, e.g. by a suitable forming and/or shaping method, or can comprise several pieces.
Preferably the whole preform for generating the integral insulating element is made of the same insulating material, especially the same glass powder.
Using a shaped preform is generally beneficial - preferably in combination with compression provided by the base body in the case of a compression seal - that a close connection between insulating material and base body and insulating material and pin is formed, even if there is no substance-to-substance bond but a form-lock join. In that way, a glass-to-metal-seal that preferably is hermetically sealed may result.
Preferably a base body with at least one stepped through hole may be provided and the above-described method is used.
Preferably a Ni-plated pin and/or a Ni-plated base body may be provided and the above-described method is used.
The features and characteristics of the feedthrough assembly and advantageous features, embodiments and variants thereof as well as advantages associated therewith have already been described above in connection with the description of the product. Reference is made to this in order to avoid repetition.
Preferably the electrical feedthrough assembly described herein is configured as an electric compressor terminal, wherein the base body is configured for attachment to a housing of an electric compressor. The feedthrough assembly may be configured as part of a housing of the electric compressor or may be attached to a housing or a part of a housing for an electric compressor.
Accordingly, it is a further aspect of the invention to provide an electric compressor comprising at least one of the electrical feedthrough assemblies described herein.
It is to be understood that the features mentioned above and those to be explained below can be used not only in the combination indicated in each case, but also in other combinations or alone, without leaving the scope of the present invention.

Description of figures

The invention will now be further explained with reference to the following figures. They show:

Figs 1: schematic and not drawn to scale depiction of a known electrical feedthrough assembly,
Fig 2 to 13: schematic and not drawn to scale depictions of electrical feedthrough assemblies according to embodiments of the disclosure.

Fig. 1 shows a sectional view of a portion of electrical feedthrough assembly 1 which is known in the prior art. Electrical feedthrough assembly, especially for the attachment to a housing, preferably a housing for an e-compressor, an electrical storage device, a pressure sensor or the like, comprises a base body 3 having a first side 31 and an opposite second side 33, the base body 3 comprising at least one through hole 5 and at least one pin 7 arranged within through hole 5 wherein the pin 7 is electrically insulated from base body 3 and sealed in through hole 5 by a sealing element 9' made of insulating material, e.g. glass, so that at least one feedthrough 2 is formed in base body 3. The sealing element 9' extends between the pin 7 and the base body 3 and surrounds the pin 7. Outside the through hole 5 between pin 7 and base body 3 a cylindrical insulating sleeve 11' made of ceramic is provided around the pin 7 at the first side 31 of the base body 3. The ceramic insulating sleeve 11' has a cylindrical outer shape, is provided here in the form of a circular hollow cylinder-shaped body, placed around the pin 7 and sealed or adhered to a surface of the sealing element 9' that is holding the pin 7 in the through hole 5 of the base body 3. The insulating sleeve 11' increases an insulation distance, i.e. creepage distance, between pin 7 and base body 3 and also enables a connection with a connector or plug (not shown) which may be put onto the pin 7 on the first side 31.
However, as can be seen, there is a gap 8 between the outer surface of the pin 7 and the surrounding inner surface of the hollow cylinder-shaped insulating sleeve 11' associated with e.g. the risk that liquid, humidity and/or wear can penetrate into the gap 8 and cause short circuit. A further drawback is that the fastening of the separate insulating sleeve 11' requires additional mounting effort during manufacture of the feedthrough assembly. Further, such known feedthrough assemblies comprise different kinds of insulating materials connected to one another having different thermal properties - especially thermal expansion properties. If e.g. thermal or compressive stress or mechanical force is applied to the connection between the sealing element 9' and the insulating sleeve 11', cracks can be formed in the connection region providing short circuit paths. Because of the gap 8, pin 7 and insulating sleeve 11' have a certain amount of play in relation to each other so that the latter can break upon load. In the worst case the insulating sleeve 11' can get lost.
To keep the illustrations in Figs. 2 to 13 clear, dimensions (such like for lengths and diameters related to (further) insulating sleeve portion and for diameter of a "simple" through hole etc.) used in connection with describing the invention are depicted in Fig. 11. In the Figures the same components and features are labelled with the same reference numbers.
Fig. 2 shows a sectional view of a portion of electrical feedthrough assembly 1 according to a first embodiment of the invention. The electrical feedthrough assembly is suited especially for the attachment to a housing, preferably a housing for an e-compressor, an electrical storage device, a pressure sensor or the like. As already explained above it comprises a base body 3 having a first side 31 and an opposite second side 33, the base body 3 comprising at least one through hole 5 connecting the first side 31 and the second side 33 and at least one pin 7 arranged within through hole 5 wherein the pin 7 is electrically insulated from base body 3 and sealed in through hole 5, so that at least one feedthrough 2 is formed in base body 3. Here the through hole is a "simple" through hole having just one diameter a2 (not denoted here, see Fig. 11). The feedthrough comprises a sealing portion 9 made of insulating material, extending between the pin 7 and the base body 3 and surrounding the pin 7. Thus, the sealing portion 9 corresponds to the sealing element 9' described above in connection with Fig. 1. The insulating material seals both against an inner wall of the through hole 5 and against the surface of the pin 7, so that the through hole 5 is tightly closed by the sealing material and a metal-insulating material-feedthrough is formed. Further, an insulating sleeve portion 11 is provided around the pin 7 at the first side 31 of the base body 3 outside the through hole 5, wherein the insulating sleeve portion 11 has a cylindrical part 13 having a length s2 that is at least 50% of the length s1 of the insulating sleeve portion 11, wherein length s1, s2 are measured in direction of a longitudinal axis 23 of the pin 7 (length s1 and s2 are denoted in Fig. 11). The insulating sleeve portion 11 is protruding beyond the base body 3 and corresponds to the insulating sleeve 11' described above in connection with Fig. 1.
As can be seen in Fig. 2 in the feedthrough assembly 1 according to the invention, the sealing portion 9 and the insulating sleeve portion 11 are present in one piece in the form of an integral insulating element 15 made of insulating material wherein the insulating material comprises glass or consists of glass or is made of glass. The glass is sealed both to the pin 7 and to the wall of the through hole 5 so that a glass-to-metal feedthrough 2 is formed. This achieves numerous advantages: tight seal - preferably a hermetic tight seal -, increased creepage distance and improved insulation properties are provided with a lower number of individual parts to be assembled during manufacture. In this advantageous embodiment, the insulating sleeve portion 11 and the sealing portion 9 are made of the same insulating material. However, other variants may be possible, e.g. using glasses for the different portions that match to each other so that the insulating materials can be melted together and form the integral insulating element 15. Further, the insulating sleeve portion 11 of the integral insulating element 15 is sealed to the surface of the pin 7, i.e. there is no gap between those components of the feedthrough 2 which reduces the risk of short circuit as well as break and loss of the insulating sleeve portion and thus leads to an improved mechanical strength and overall more robust design of the feedthrough assembly 1. The integral insulating element 15 and its design and arrangement overcome disadvantages of the prior art electrical feedthrough assembly described above in connection with Fig. 1.
As can be seen the insulating sleeve portion 11 has a cylindrical part 13 protruding beyond the base body 3 having a length s2 (not denoted here, see Fig. 11) that is at least of 50% - here more than 80% - of the length s1 of the insulating sleeve portion 11. In form of the cylindrical part 13 a standardized geometry is provided which is beneficial for connecting the pin 7 to a device, e.g. by pushing a connector or plug (not shown) onto the pin and the insulating sleeve portion 11. As can be seen, in an area near an edge 6 of the through hole 5 and/or an area near an end face 12 of the insulating sleeve portion 11 facing away from the base body 5 the outer shape of the insulating sleeve portion 11 may deviate from the cylinder shape, e.g. there can be a curved surface section and/or a chamfered surface section. During manufacture of the assembly, the cylindrical part 13 has been formed in contact with a correspondingly shaped mould, e.g. a graphite mould. Thus, cylindrical part 13 of insulating sleeve portion 11 has predominantly a moulded surface preferably having a surface roughness Ra (arithmetic average surface roughness) of more than 0,4 µm. Such a roughness improves the mechanical hold for a connector. Here, a surface of the end face 12 of the insulating sleeve portion 11 may be a predominantly moulded surface with corresponding roughness, too.
In the first embodiment an outer diameter a1 (not denoted here, see Fig. 11) of the cylindrical part 13 is smaller than a diameter a2 (not denoted here) of the through hole 5 of the base body 3 at the first side 31. This can be beneficial for a feedthrough assembly wherein the pin 7 is fixed inside the through hole 5 via a compression seal. In a compression seal the base body 3 provides compression to the sealing portion 9 with inserted pin 7. In the area of the edge 6 of the through hole 5 a decrease of compression may induce stress in the insulating material in the transition zone between sealing portion 9 located inside the through hole 5 and the insulating sleeve portion 11 protruding beyond the base body 5 and being located outside the through hole 5 which could lead to cracks in the glass. This can be avoided by such an arrangement because less compression stress is exerted by the base body 3 on the transition zone between sealing portion 9 and insulating sleeve portion 11 reducing the risk of generating cracks in the insulating material. However, this dimension and design of the cylindrical part 13 may of course be beneficial in a feedthrough where the coefficient of expansion of the base body and the coefficient of expansion of the insulating material are adapted to each other.
In the first embodiment of the feedthrough assembly 1 an end face 10 of the sealing portion 9 of the integral insulating element 15 at the second side 33 of the base body 3 is essentially flush with the surface of the base body 3, i.e. there is a "flush arrangement" of the sealing portion or integral insulating element. This enables a flat design of the second side 33 of the base body 3. Alternatively at its second side 33 the base body 3 may protrude beyond the end face 10 of the sealing portion or integral insulating element (so called "recessed arrangement" of the sealing portion), or the integral insulating element 15 may comprise further features as described below in connection with Fig. 4 and 5.
The electrical feedthrough assembly 1 shown is particularly suitable for use in connection with e-compressors. Preferably the feedthrough assembly 1 may be a component of a housing of an e-compressor wherein the feedthrough assembly 1 is placed in an opening of an e-compressor housing and is attached to the housing. Inside the housing a motor of an e-compressor is usually arranged. The at least one pin 7 of the at least one feedthrough 2 of the feedthrough assembly 1 enables electrical connection between the motor arranged inside the housing and e.g. an inverter arranged outside the housing. An e-compressor may have several electrical feedthroughs assemblies 1 having just one feedthrough 2 and just one pin 7. Alternatively or additionally, the feedthrough assembly 1 may have a base body 3 which comprises more than one feedthrough 2 and thus more than one pin 7 and more than one through hole 5 which is explained below in connection with Figs. 12 and 13.
Advantageously the first side 31 of the base body 3 with protruding insulating sleeve portion 11 may be the side facing the motor or driving system in the e-compressor arranged in the housing - referred to as motor side - when the feedthrough assembly 1 is attached to the housing. The insulating sleeve portion 11 increases the creepage distance between the base body 3 and the pin 7 by increasing the insulation distance therebetween. This helps to prevent insulation degradation and electrical shorts caused, for example, by fine metal powders (such as wear debris or chips from a drive system inside a compressor) sticking between base body, insulating sleeve portion and pin.
In an advantageous alternative, the first side 31 of the base body 3 with protruding insulating sleeve portion 11 may be the side facing the inverter of the e-compressor - referred to as inverter side - when the feedthrough assembly is attached to a housing. Such an embodiment is exemplarily indicated in the following Fig. 3 in which the protruding insulating sleeve portion 11 points in the other direction - "upwards" instead of "downwards". At the inverter side the insulating sleeve portion bonded to the pin surface may provide a seal against moisture besides providing an insulation distance.
In an advantageous example of the first embodiment according to the invention and advantageous examples of the embodiments shown in the following figures, the base body 3 may comprise stainless steel having a thermal expansion coefficient CTE in the range of 10 to 14 * 10^-6/K, the insulating material may comprise glass having a CTE in the range of 8 to 10 * 10^-6/K and the pin 7 may comprise a metal having a CTE in the range of 9 to 10 * 10^-6/K. In order to provide a compression seal feedthrough, thermal expansion coefficient of the base body 3 is selected so as to be larger than the thermal expansion coefficient (CTE) of the insulating material such that, after a thermal treatment in which the insulating material melts and is glazed in the through hole, during cooling thermal contraction of the base body 3 is stronger than in the insulating material of sealing portion 9. The pin 7 may comprise stainless steel or a Ni-Fe- material or a Fe-Cr material or a central core made of copper surrounded by stainless steel or a central core made of copper surrounded by a Ni-Fe-material.
In advantageous alternative examples of embodiments of the invention shown e.g. in Fig. 2 to 13, the materials of the components can be selected such that the coefficient of thermal expansion of the base body and the coefficient of thermal expansion of the insulating material are adapted to each other. It is preferable if the difference between the coefficients of thermal expansion is less than 5%. In particular, an adapted feedthrough is understood to mean that the coefficients of thermal expansion substantially differ by a maximum of 1 * 10-6 1/K, in particular are substantially the same. For example, a base body made of Ni-Fe-Co alloy may be combined with an insulating material comprising borosilicate glass and a pin made of Ni-Fe-Co alloy.
In Fig. 3 a second embodiment of the feedthrough assembly 1 with integral insulating element 15 is shown. The structure of the feedthrough assembly 1 corresponds to the first embodiment described with reference to Fig. 2. Deviating from this the outer diameter a1 (not denoted here, diameters are shown in Fig. 11) of the cylindrical part 13 of the insulating sleeve portion 11 is essentially as great as a diameter a2 of the through hole 5 of the base body 3 at the first side 31. As explained above this may be beneficial because the preform for integrally forming the sealing portion and the insulating sleeve portion may be less complex to manufacture. Alternatively, it may also be possible that the outer diameter a1 of the cylindrical part 13 of the insulating sleeve portion 11 is greater than a diameter a2 of the through hole 5, so that the edge 6 of the through hole 5 is covered by insulating material.
Comparing embodiments of Fig. 2 and Fig. 3, the insulating sleeve portion 11 points in another direction in Fig. 3 ("upwards" instead of "downwards"). This exemplarily indicates that the first side 31 of the base body 3 with protruding insulating sleeve portion 11 may be the side facing away from the motor, e.g. facing the inverter of the e-compressor - referred to as inverter side - when the feedthrough assembly 1 is attached to a housing. However, of course the second embodiment may also be arranged so that the first side 31 faces the motor side.
In Fig. 4 a third embodiment of the feedthrough assembly 1 with integral insulating element 15 is shown. The structure of the feedthrough assembly 1 at the first side 31 corresponds to the first embodiment described with reference to Fig. 2. Deviating from the first embodiment the sealing portion 9 comprises an arc shaped extending portion 17 of the sealing material such that the sealing portion 9 extends beyond the second side 33 of the base body 3 along the pin 7 and completely surrounds it, wherein the extending portion 17 is in contact with the pin 7. The arc shaped extending portion has a diameter a6 that decreases from the second side 33 of the base body 3 along the pin 7, thereby forming an arc, i.e. the arc shaped extending portion 17 has a curved outer surface. In other words, in the third embodiment the insulating sleeve portion 11 arranged at the first side 31 of the base body 3, the sealing portion 9 arranged within the through hole 5 and the arc shaped extending portion 17 of the sealing material arranged at the second side 33 of the base body 3 are present in one piece in the form of the integral insulating element 15. The arc shaped extending portion 17 of the integral insulating element 15 increases the creepage distance between the base body 3 and the pin 7 at the second side 33 of the base body 3. The arc shaped extending portion 17 is formed by surface tension and/or capillary forces between molten glass and pin during the sealing process when the insulating material of a preform is molten, i.e. it is formed without contact to a mould. Thus, the curved surface of the extending portion 17 has a fire polished surface. However, because of the curved surface which can be less standardized in geometry compared with e.g. a formed cylindrical part of the insulating sleeve portion, an additional connection element around the arc shaped glass extension 17 may be needed to provide a good connectability of the pin at the second side 33.
In a variation, the outer diameter a1 of the cylindrical part 13 of the insulating sleeve portion 11 at the first side may be smaller than the exemplarily shown diameter (e.g. as shown in Fig. 5) or could be larger than the exemplarily shown diameter, for example it could be essentially as great as the diameter a2 of the through hole 5 of the base body 3 at the first side 31 (e.g. as shown in Fig. 3).
In Fig. 5 a fourth embodiment of the feedthrough assembly 1 with integral insulating element 15 is shown. The structure of the feedthrough assembly 1 at the first side 31 is similar to the embodiments described with reference to Fig. 2 or 4. Deviating from these embodiments the feedthrough assembly 1 comprises a further insulating sleeve portion 19 provided around the pin 7 at the second side 33 of the base body 3 outside the through hole 5 and sealed to the pin 7. The further insulating sleeve portion 19 protrudes beyond the base body 3 and has a further cylindrical part 21 having a length s2' (not denoted here, see Fig. 11) which is at least 50% of the length s1' of the further insulating sleeve portion 19, measured in direction of a longitudinal axis 23 of the pin 7. In this embodiment the further insulating sleeve portion 19, the sealing portion 9 and the insulating sleeve portion 11 are present in one piece in the form of an integral insulating element 15 made of insulating material wherein the insulating material comprises glass or consists of glass or is made of glass. Such an embodiment is very advantageous, as the creepage distance, i.e. insulation distance, between base body 3 and pin 7 provided at the second side 33 of the base body 3 is increased, too. Because of the further cylindrical part 23 a better connectability of the pin 7 with connecting means can provided at the second side 33 of the base body 3 compared to an embodiment with arc shaped extending portion (for example as shown in Fig. 4). Preferably the further insulating sleeve portion 19 is made of the same insulating material as the sealing portion 9 and/or the insulating sleeve portion 11, but it does not have to be like that as explained above in connection with Fig. 2. In a preferred variant the further insulating sleeve portion 19, the insulating sleeve portion 11 and the sealing portion 9 are made of the same insulating material.
In the fourth embodiment the outer diameter a3 (not denoted here, see Fig. 11) of the further cylindrical part 21 of the further insulating sleeve portion 19 is essentially as great as a diameter a2 of the through hole 5 of the base body 3 at the second side 33. However, this is just an example. In principle the outer diameter a3 of the further cylindrical part 21 may also be smaller or even larger than the diameter of the through hole 5 of the base body 3 at the second side 33 as described above. Further, the dimensions of the insulating sleeve portion 11 at the first side 31 are just an example and may vary correspondingly, for example the insulating sleeve portion 11 may have a larger outer diameter a1 than the further insulating sleeve portion 19 as shown in Fig. 11. Further, the outer diameters a1, a3 of the cylindrical parts 13, 21 may be even essentially identical to each other. The length s1 of the insulating sleeve portion 11 and the length s1' of the further insulating sleeve portion 19 and/or the length s2 of the cylindrical part 13 of the insulating sleeve portion 11 and the length s2' of the further cylindrical part 21 of the further insulating sleeve portion 19 may be the same or may be different depending e.g. on the design of the feedthrough assembly 1 and the needed insulation distance and/or connectability to a connector or plug. In principle, any combination is conceivable.
In Figs. 6 to 9 embodiments of the feedthrough assembly are shown in schematic and not to scale depictions having at least one so called "stepped through hole" having at least two different diameters unlike a simple through hole having just one diameter (as shown in Figs. 2 to 5, 11 to 13). The insulating material of the integral insulating element 15 is present in the different parts of the stepped through hole as described below.
To keep the illustrations in Figs. 6 to 9 clear, dimensions, especially diameters a4, a5, used in connection with describing the stepped through hole are just depicted in Figs. 6 and 9.
In Fig. 6 a fifth embodiment of the feedthrough assembly 1 with integral insulating element 15 is shown. The structure of the feedthrough assembly 1 at the first side 31 is similar to the first embodiment described with reference to Fig. 2. Deviating from the first embodiment the through hole 5 is configured as a stepped though hole 5 having at least one surface part 5a adjacent to a side of the base body 3 (here the first side 31) and a middle part 5b, wherein a diameter a4 of the surface part 5a is larger than a diameter a5 of the middle part 5b and wherein the insulating material of the sealing portion 9 is present in both the middle part 5b and in the at least one surface part 5a of the through hole 5. In this example, the height h1 of the at least one surface part 5a is smaller than half the thickness t of the base body 3. Alternatively, h1 may be half the thickness t of the base body (as e.g. shown in fig. 7) or may even be greater. The surface part 5a having the enlarged diameter a4 compared to the diameter a5 of the middle part 5b is arranged here at the first side 31 of the base body 3 where the insulating sleeve portion 11 is located so that a long creepage distance is provided. The middle part 5b of the stepped through hole 5 holds the sealing portion 9 and - especially in the case of a compression feedthrough or seal - serves for providing a pressure on the sealing portion 9 helping to provide a tight seal and fixture of the pin 7.
In the fifth embodiment the outer diameter a1 (not denoted here, see Fig. 11) of the cylindrical part 13 of the insulating sleeve portion 11 is smaller than the diameter of the through hole 5 of the base body 3 at the first side 31, i.e. smaller than the diameter a4 of the surface part 5a. However, as described above in connection with the first embodiment and as can be seen in the sixth embodiment shown in Fig. 7, this need not be the case describe now.
In Fig. 7 a sixth embodiment of the feedthrough assembly 1 with integral insulating element 15 is shown. The structure of the feedthrough assembly 1 at the first side 31 is similar to the fifth embodiment described with reference to Fig. 6. Deviating from the fifth embodiment, the outer diameter a1 (not denoted here, diameters are shown in Fig. 11) of the cylindrical part 13 of the insulating sleeve portion 11 is essentially as great as a diameter of the through hole 5 of the base body 3 at the first side 31, i.e. as great as the diameter a4 of the surface part 5a of the stepped through hole. Further deviating from the fifth embodiment, the height h1 of the surface part 5a is about as great as half the thickness t of the base body 3.
In Fig. 8 a seventh embodiment of the feedthrough assembly 1 with integral insulating element 15 is shown. The structure of the feedthrough assembly 1 at the first side 31 is similar to the first embodiment described with reference to Fig. 2. Deviating from the first embodiment the through hole 5 is formed as a stepped through hole as described in Fig. 6, however, the surface part 5a having the enlarged diameter a4 is arranged at the second side 33 of the base body 3 and filled with insulating material thus providing an extension of the creepage distance between base body 3 and pin 7 although the end face 10 is flush.
Generally, if the stepped through hole has only one surface part 5a with enlarged diameter, the surface part may be arranged at the first side 31 of the base body 3 where the insulating sleeve portion is located (as depicted e.g. in Fig. 6, 7). Alternatively, it may be arranged at the second side 33 of the base body 3 wherein the surface part 5a with enlarged diameter provides an increased creepage distance either alone (as shown e.g. in Fig. 8) or in combination with a further feature, e.g. a further insulating sleeve portion 19 (as exemplarily shown in Fig. 5) or an arc shaped extending portion 17 (as exemplarily shown in Fig. 4).
In Fig. 9 an eighth embodiment of the feedthrough assembly 1 with integral insulating element 15 is shown. The structure of the feedthrough assembly 1 at the first side 31 is similar to the fifth embodiment described with reference to Fig. 6. Deviating from the fifth embodiment the stepped through hole comprises surface parts 5a formed on both sides 31, 33 of the base body 3, both having diameters a4 being larger than the diameter a5 of the middle part 5b of the through hole 5. Here, surface parts 5a are both formed identically on both sides 31, 33 of the base body 3. However, in a variant surface parts 5a may be different e.g. in terms of diameter and/or height. As shown here, the heights h1 of surface parts 5a are smaller than half the thickness t of base body 3. Middle part 5b has height h2. It is noted here that the middle part 5b is that part of the base body 3 that in particular may provide compression - especially in case of a compression feedthrough - in order to hermetically seal the feedthrough which may be a preferred effect of a middle part 5b in any of the feedthrough assemblies of the disclosure and not being limited to any of the special embodiments, examples and exemplary depictions of electrical feedthrough assemblies of the disclosure. Of course, surface parts 5a provide for an enlarged creepage distance for pin 7, and here, in the exemplary embodiment of Fig. 9, on both sides 31, 33 of electrical feedthrough assembly 1. This enlargement creepage distance, as already stated above, is an advantageous effect of a surface part 5a in any of the feedthrough assemblies of the disclosure and not being limited to any of the special embodiments, examples and exemplary depictions of electrical feedthrough assemblies of the disclosure.
Figs. 6 to 9 show examples of embodiments in which the end face 10 of the sealing portion 9 and thus integral insulating element 15 is flush at the second side 33 of the base body 3. Of course, this does not have to be the case. Alternatively, a further insulating sleeve portion 19 could be provided (e.g. corresponding to or similar to Fig. 5) or an arc shaped extending portion 17 could be provided, as explained by way of example in Fig. 4.
Of course, the designs, arrangements, dimensions etc. of features like (further) insulating sleeve portion(s) 11, 19, arc shaped extending portions 17, simple through holes, stepped through holes etc. can be freely combined and are not limited to the variants shown as examples, especially if the feedthrough assembly has more than one feedthrough. A feedthrough assembly with three feedthroughs is exemplarily shown and described in Figs. 12 and 13.
Fig. 10 shows a nineth embodiment of the feedthrough assembly 1 with integral insulating element 15. The structure of the feedthrough assembly 1 at the first side 31 is similar to the first embodiment described with reference to Fig. 2. In the nineth embodiment the pin 7 comprises Ni-plating 25 in an entire contact area ca with the integral insulating element 15, i.e. with the sealing portion 9 and with the insulating sleeve portion 11. Ni-plating 25 is here a plating that covers the whole surface of pin 7. Also, in the depiction of Fig. 10, base body 3 likewise comprises a Ni-plating in an entire contact area ca with the integral insulating element 15, i.e. with the sealing portion 9, that is, Ni-plating 27. Generally, base body 3 and/or pin 7 may be Ni-plated prior to assembly of electrical feedthrough assembly 1. In the exemplary embodiment shown, both pin 7 and base body 3 are Ni-plated prior to assembly of electrical feedthrough assembly 1 as they comprise a Ni-plating in the entire contact areas ca with the integral insulating element 15 where the insulating material contacts and covers the surface of pin 7 and the wall of the through hole 5 of the base body 3. Preferably the surface roughness R_z of the Ni-plated pin and/or Ni-plated base body 3, especially in the contact area ca, is at most 8 µm.
Generally, using a base body 3 and/or pin 7 being Ni-plated prior to assembly of electrical feedthrough assembly 1 is beneficial because it is not necessary any more to Ni-plate the electrical feedthrough assembly after its assembly in order to provide the required highly conductive, corrosion protected surfaces necessary for the application. As a Ni-plated surface may not be easily wetted or contacted by glass it may be advantageous to shape the preform of the later integral insulating element and to use corresponding moulds during assembling. Additionally or alternatively, it may be preferred for achieving a tight, preferably hermetic seal to select the materials of the feedthrough assembly so that the coefficient of thermal expansion of insulating material 9 is smaller than the coefficient of thermal expansion of base body 3 so that compression seal feedthrough 2 is provided.
Of course, a base body 3 and/or pin 7 being Ni-plated prior to assembly of electrical feedthrough assembly 1 may advantageously also be combined with stepped through holes e.g. as described above in connection with Figs. 6 to 9. Also generally, in all depictions of Figs. 2 to 9, pin 7 may comprise Ni-plating 25. Also generally, at least one pin 7 of feedthrough assemblies 1 in Figs. 12 and 13 may comprise Ni-plating 25. Also, it is generally possible that base body 3 in all depictions of Figs. 2 to 9, 11 to 13 comprises Ni-plating 27. Alternatively, in all depictions of Figs. 2 to 13 the base body and/or at least one pin may have an oxidized surface or a bare surface.
In Fig. 11 a variant of the embodiment of Fig. 5 is shown. In addition, diameters and lengths for selected features are entered in this figure as representative for all figures.
Fig. 12 is a plain view of the first side 31 of electrical feedthrough assembly 1 according to a tenth embodiment of the disclosure. Feedthrough assembly 1 comprises, in the embodiment depicted schematically and not drawn to scale, three feedthroughs 2 wherein the structure of the feedthroughs 2 is exemplarily similar to the first embodiment described with reference to Fig. 2. Each feedthrough 2 comprises sealing portion, made of a glass material as insulating material, that insulates pin 7 electrically from base body 3 and seals pin 7 within through hole 5. Each feedthrough 2 comprises an insulating sleeve portion 11 being made in one piece with the sealing portion 9 thus providing an integral insulating element 15. Further, electrical feedthrough assembly 1 comprises mounting bores 29 for fastening the electrical feedthrough assembly 1 to a housing (not depicted here). Also denoted are center points cp of pins 7 in order to further illustrate the distance d between pins 7 that are, in the electrical feedthrough assembly 1 depicted here, aligned in a straight line. Distance d between the at least two pins 7 is determined as a distance d between a center point cp of one pin 7 to a center point cp of the other, adjacent pin 7. In order to provide a small overall design of the feedthrough assembly, the distance d may advantageously be chosen to be in the range of at least 1.2 times and at most 1.6 times of the diameter a2 of the at least one through hole 5 or - in the case of a stepped through hole (not depicted here) - of at least 1.2 times and at most 1.6 times of the diameter a4 of the at least one through hole in the middle part 5b thereof. Preferably, the distance between all pins of the electrical feedthrough assembly 1 of the disclosure is in that range.
Fig. 12 also shows the in general "elongated" shape of plate-like base body 3, which means that length I of base body 3 is larger than width w.
Fig. 13 shows a cross sectional view of the electrical feedthrough assembly 1 of Fig. 12 (along line A-A). The elongated plate-like shape of base body 3 can be seen with thickness t of base body 3 being smaller than length I of base body 3. Electrical feedthrough assembly 1 comprises three through holes 5 so that three feedthroughs 2 result by sealing, in each of through holes 5, pins 7 by insulating material, preferably a glass material. Further, in each feedthrough 2 the sealing portion 9 and the insulating sleeve portion 11 are present in one piece in the form of an integral insulating element 15. Further the insulating sleeve portions 11 are sealed to the surfaces of the pins 7. Here, all through holes 5 of the feedthrough assembly of the disclosure are formed as "simple" through holes having just one diameter. It is to be noted here that in this special example all through holes 5 of electrical feedthrough assembly 1 are formed, of course within limits of standard manufacture tolerances, identically. But it does not have to be. Further, for this embodiment for all feedthroughs 2, integral insulating elements 15 are exemplarily flush to the surface of the base body 3 at the second side 33. Of course, arc shaped extending portions 17 of the insulating material (as exemplarily shown in Fig. 4) and/or further insulating sleeve portions 19 (as exemplarily shown in Fig. 5) may be formed at the second side 33 of base body 3. Generally, all combinations of flush arrangement, arc shaped extending portions 17 and (further) insulating sleeve portions 11, 19 may be possible.
In a variant (not shown), all through holes 5 may be formed as so-called stepped through holes as described e.g. in connection with Figs. 6 to 9. The surface parts 5a may be arranged at the first side 31 and/or the second side 33 of the base body 3. Further preferably, generally, all stepped through holes 5 of an electrical feedthrough assembly 1 of the disclosure may be arranged and formed correspondingly, preferably identically within limits of standard manufacture tolerances. In other words, if the creepage distance provided by the insulating sleeve portions 11 alone is too small, a stepped through hole may be used to further extend the creepage distance by its enlarged surface part 5a. Especially in such combination a small distance d between the at least two pins 7 may be realized, especially if a compression seal is present. Generally, this measure makes it possible to provide particularly small feedthrough assemblies with a small distance between adjacent pins, high creepage distance and good connection of the insulating material of integral insulating element 15 to the metal parts.
Preferably, all through holes 5 and all feedthroughs 2 of feedthrough assembly 1 may be formed, within limits of standard manufacture tolerances, identically which is shown in Figs. 12 and 13.
It is also noted here, that a2, a4, and a5 are called "diameters" here, as preferably, through holes 5 are formed having a circular (or round) shape. However, in case through holes 5 have a shape different from a circular shape, "diameters", in the sense of the disclosure, are understood to refer to the largest lateral dimension of through hole 5 in parallel to side 31, 33 of base body 3. The same applies to the diameters a1, a3 of the (further) insulating sleeve portions 11, 19. Also, generally, sides 31, 33 of base body 3 are in parallel to each other, as depicted in Figs 1 to 11, 13.
The electrical feedthrough assembly of the disclosure enables an easy to manufacture and very compact robust overall design of such a component which can be contacted easily e.g. by a connector or plug. Further the feedthrough assembly has improved electric insulation and sealing properties provided by the integral insulating element having the insulating sleeve portion protruding beyond the base body and sealed to the surface of the pin. The number of individual parts of a feedthrough assembly is reduced. Thus, a technically simple solution is provided that leads to a faster, more cost-effective production and safer and more robust design. Thus, the electrical feedthrough assembly is designed and manufactured to enable the transfer of large amounts of energy from the battery to the air conditioning compressor and at the same time remain reliably gas-tight to prevent any leakage, especially of refrigerant and can therefore be used as component in an electric compressor. Furthermore, electric compressors are affected by high pressure, high humidity and vibration. The feedthrough assembly of the disclosure is able to withstand such adverse conditions. Furthermore, it has extremely high insulation resistance and high voltage capabilities for e.g. 48 V electrical systems.

Besides e-compressors, electrical feedthrough assemblies of the disclosure can be used in other applications where there are strict requirements, for example with regard to hermetic tightness, temperature resistance, thermal shock resistance, etc. In particular, they can be used in pressure sensors, in electrical storage devices, like batteries, accumulators, capacitors, etc.

Reference numerals

1	electrical feedthrough assembly
2	feedthrough
3	base body
5	through hole
5a	surface part of a stepped through hole
5b	middle part of a stepped through hole
6	edge of through hole 5
7	pin
8	gap
9	sealing portion
9'	sealing element
10	end face of sealing portion 9
11	insulating sleeve portion
12	end face of insulating sleeve portion 11
13	cylindrical part of insulating sleeve portion 11
15	integral insulating element
17	arc shaped extending portion of 9
19	further insulating sleeve portion
21	further cylindrical part of further insulating sleeve portion 19
23	axis of pin 7
25	Ni-plating of pin 7
27	Ni-plating of base body 3
29	mounting bore
31	first side of base body 3
33	second side of base body 3
ca	contact area
cp	center point
d	distance between pins, pitch
t	thickness of base body 3
w	width of base body 3
l	length of base body 3
a1	outer diameter of cylindrical part 13
a2	diameter of through hole 5
a3	outer diameter of further cylindrical part 21
a4	diameter of surface part of 5a
a5	diameter of middle part of 5b
a6	diameter of arc shaped extending portion 17
h1	height of surface part 5a
h2	height of middle part 5b
s1	length of insulating sleeve portion 11
s1'	length of further insulating sleeve portion 19
s2	length of cylindrical part 13
s2'	length of further cylindrical part 21
A-A	line for cross section

Claims

Electrical feedthrough assembly (1), especially for the attachment to a housing, preferably a housing for an e-compressor, an electrical storage device, a pressure sensor or the like, comprising
- a base body (3) having a first side (31) and a second side (33), the base body (3) comprising at least one through hole (5) and

- at least one pin (7) arranged within the at least one through hole (5) that is electrically insulated from the base body (3) and sealed in the through hole (5) by a sealing portion (9) made of an insulating material so that at least one feedthrough (2) is formed in the base body (3), wherein the sealing portion (9) extends between the pin (7) and the base body (3) and surrounds the pin (7),

- an insulating sleeve portion (11) provided around the pin (7) at the first side (31) of the base body (3) outside the through hole (5), wherein the insulating sleeve portion (11) has a cylindrical part (13) having a length (s2) that is at least 50% of the length (s1) of the insulating sleeve portion (11), wherein length is measured in direction of a longitudinal axis (23) of the pin (7), characterized in that
- the sealing portion (9) and the insulating sleeve portion (11) are present in one piece in the form of an integral insulating element (15) made of insulating material wherein the insulating material comprises glass or consists of glass or is made of glass, and

- the insulating sleeve portion (11) is sealed to the pin (7).
Electrical feedthrough assembly according to claim 1, characterized in that the insulating sleeve portion (11) and the sealing portion (9) are made of the same insulating material.
Electrical feedthrough assembly according to any of claims 1or 2, characterized in that an outer surface of the cylindrical part (13) of the insulating sleeve portion (11) is predominantly a moulded surface.
Electrical feedthrough assembly according to any of claims 1 or 3, characterized by at least one of the following features:
- an outer diameter (a1) of the cylindrical part (13) of the insulating sleeve portion (11) is essentially as great as a diameter (a2) of the through hole (5) of the base body (3) at the first side (31),

- an outer diameter (a1) of the cylindrical part (13) of the insulating sleeve portion (11) is smaller than a diameter (a2) of the through hole (5) of the base body (3) at the first side (31).
Electrical feedthrough assembly according to any of claims 1or 4, characterized by at least one of the following features:
- at the second side (33) of the base body (3) an end face (10) of the sealing portion (9) of the integral insulating element (15) is essentially flush with the surface of the base body (3) or the second side of the base body (3) may protrude above an end face (10) of the sealing portion (9),

- at the second side (33) of the base body (3) the sealing portion (9) of the integral insulating element (15) comprises an arc shaped extending portion (17) of the sealing material such that the sealing portion (9) extends beyond the second side (33) of the base body (3) along the pin (7) and completely surrounds it, wherein the arc shaped extending portion (17) has a diameter (a6) that decreases from the second side (33) of the base body (3) along the pin (7), thereby forming an arc,

- at the second side (33) of the base body (3) a further insulating sleeve portion (19) is provided around the pin (7) outside the through hole (5) and is sealed to the pin (7), wherein the further insulating sleeve portion (19) has a further cylindrical part (21) having a length (s2') that is at least 50% of the length (s1') of the further insulating sleeve portion (19), measured in direction of a longitudinal axis (23) of the pin (7), wherein the further insulating sleeve portion (19), the sealing portion (9) and the insulating sleeve portion (11) are present in one piece in the form of the integral insulating element (15), wherein preferably the further insulating sleeve portion (19) is made of the same insulating material as the sealing portion (9) and/or the insulating sleeve portion (11).
Electrical feedthrough assembly according to claim 5, characterized by at least one of the following features:
- an outer diameter (a3) of the further cylindrical part (21) of the further insulating sleeve portion (19) is essentially as great as a diameter (a1) of the through hole (5) of the base body (5) at the second side (33),

- an outer diameter (a3) of the further cylindrical part (21) of the further insulating sleeve portion (19) is smaller than a diameter (a1) of the through hole (5) of the base body (3) at the second side (33).
Electrical feedthrough assembly according to any of claims 1or 6, characterized in that at least one through hole (5) is configured as a stepped through hole having at least one surface part (5a) adjacent to a side of the base body (3) and a middle part (5b), wherein a diameter (a4) of the surface part (5a) is larger than a diameter (a5) of the middle part (5b), and wherein the insulating material of the integral insulating element (15) is present in both the middle part (5b) and in the at least one surface part (5a) of the stepped through hole.
Electrical feedthrough assembly according to any of claims 1or 7, characterized in that the pin (7) comprises a Ni-plating (25) in an entire contact area (ca) with the insulating material of the integral insulating element (15) and/or the base body (3) comprises a Ni-plating (27) in an entire contact area (ca) with the insulating material of the integral insulating element (15).
Electrical feedthrough assembly according to any of claims 1or 8, characterized in that the coefficient of thermal expansion of the insulating material is smaller than the coefficient of thermal expansion of the base body (3) so that a compression seal feedthrough is provided.
Electrical feedthrough assembly according to any of claims 1or 9 characterized in that the feedthrough assembly (1) comprises one or more of the following features:
- the base body (3) comprises steel, preferably stainless steel, preferably structural steel,

- the at least one pin (7) comprises stainless steel or a Ni-Fe- material or a Fe-Cr material or a central core made of copper surrounded by stainless steel or surrounded by a Ni-Fe-material,

- the insulating material of the sealing portion (9) has a coefficient of thermal expansion, CTE, between 8 * 10^-6/ K and 12 * 10^-6/K.
Electrical feedthrough assembly (1) according to any of claims 1 to 10, characterized in that the electrical feedthrough assembly is configured as an electric compressor terminal, wherein the base body (3) is configured for attachment to a housing of an electric compressor.
Electric compressor comprising an electrical feedthrough assembly (1) according to any of claims 1 to 11.