Metal-insulator-composite assembly

Abstract

The present invention relates to an assembly (1) comprising: a metallic flange (2), and an electrical insulator (3) comprising an electrically insulating material, wherein at least one spacer (6) arranged between the electrical insulator (3) and the flange (2).

Description

[0001] Applicant: BIOTRONIK SE & Co. KG

[0002] Date: 19.11.2025

[0003] Our Reference: 24.055P-WO

[0004] Metal-insulator-composite assembly

[0005] The present invention relates to a metal-insulator-composite assembly for medical devices, particularly designed as a battery lid, an electrical feedthrough or a housing part of an implantable battery or an implantable medical device. Further aspects of the present invention relate to batteries, medical implants and arrangements applicable to medical implants.

[0006] Previous solutions regarding structures such as electrical feedthroughs are often based on complex components and high process temperatures (>500°C) for glass melting processes or brazing. Often, long batch processes (e.g. brazing or glass melting processes in chamber furnaces) are required to manufacture such structures.

[0007] Typical electrical feedthroughs, e.g., for implantable batteries and / or for implantable medical devices utilize feedthrough conductors designed as a pin, which protrude into the interior of the battery of the medical device and, thus require a certain installation space. The feedthrough conductors typically connected to current collectors of the anode and / or the cathode. This requires a certain dead volume (space not contributing to the volumetric capacity) inside the battery or the implant. Particularly in case of small batteries, a significant percentage in the range of up to 10% of the achievable capacity may be lost as a result.

[0008] Based on the above, the problem to be solved by the present invention is to provide an assembly, particularly an assembly for an electrical feedthrough, that is improved regarding at least one of the above-stated difficulties, particularly to significantly reduce the dead volume while being manufacturable in a simple and reliable manner.This problem is solved by an electrical feedthrough having the features of claim 1. Further aspects of the present invention are described below. Appropriate embodiments of the aspects of the present invention are stated in the corresponding dependent claims and are described below.

[0009] According to claim 1, a (metal-ceramic-composite) assembly is disclosed, particularly for a battery and / or for an implantable medical device, the assembly comprising:

[0010] a first metallic flange, and

[0011] an electrical insulator comprising an electrically insulating material,

[0012] According to an aspect of the invention, it is particularly envisioned that the metal-ceramic-composite assembly comprises at least one spacer arranged between the electrical insulator and the flange.

[0013] According to another aspect of the invention, it is particularly envisioned that the electrical insulator is connected to the metallic flange via a solder or braze joint, the solder or braze joint comprising a solder having a melting point below 500°C, particularly below 400°C, particularly below 350°.

[0014] Particularly, the electrically insulating material is a ceramic material or a glass material. Particularly, the electrically insulator and the first flange are connected by a solder joint or braze joint.

[0015] Advantageously, the components of required for the metal-insulator-composite assembly may be assembled automatically in a single-axis assembly and may be soldered in continuous furnaces in the same way as SMT processes. Particularly by selecting certain eutectic solders, e.g. gold-based (or other chemically stable solders with a low melting point), less temperature-stable materials may be used and mechanical stresses resulting from differences in thermal expansion coefficients can be reduced in the soldering process. The processing temperature in the production of the composites may be significantly reduced.

[0016] 24.055P-WO 19.11.2025Particularly, the first flange may be coated, particularly plated, with a suitable material that may be soldered with the selected solder. Furthermore, the electrical insulator may be coated to generate a solderable surface area that may be soldered with the selected solder to create said solder joint between the electrical insulator and the first flange.

[0017] Particularly, the metal-insulator-composite assembly may be designed as a battery lid of an implantable battery, which may form a part of an implantable medical device, or a housing part of a housing of an implantable medical device. Particularly, the first metallic flange may be welded to a housing, particularly the housing of the implantable battery or a housing of an implantable medical device, wherein particularly the metal-insulator-composite assembly provides a hermetic, e.g., fluid-tight, barrier against an outside of the implantable battery or the implantable medical device.

[0018] Particularly, the combination of materials and geometries of the metal-insulator-composite according to the invention makes it possible to automatically manufacture for example battery covers with optional circuitry arranged on and / or integrated into the electrical insulator to save installation space. This results in miniaturization potential for batteries or potential for capacity increases (with the same volume). Particularly, such a design is suitable for implant batteries.

[0019] According to one embodiment of the present invention, the electrical insulator is a multilayer electrical insulator comprising a plurality of layers stacked on top of one another, the respective layer being formed or comprising the ceramic material.

[0020] Furthermore, in one embodiment, the metal-insulator-composite assembly, particularly designed as a battery lid or housing part, comprises a first outer electrical contact member and a second outer electrical contact member (e.g. contact tab) arranged on a first side of the electrical insulator as well as first and a second inner electrical contact member (e.g. contact tab) arranged on a second side of the electrical insulator, which second side faces an interior space of the battery when the battery lid is connected to a casing of the battery via the flange. Particularly, the first outer electrical contact member is electrically connected or connectable to the first inner electrical contact member via an electrically

[0021] 24.055P-WO 19.11.2025conductive first path integrated into the electrical insulator. Furthermore, particularly, the second outer electrical contact member is electrically connected or connectable to the second inner electrical contact member via an electrically conductive second path integrated into the electrical insulator. Furthermore, particularly, the first inner electrical contact member is configured to be connected to an anode of the battery, particularly via an anode current collector, while the second inner electrical contact member is configured to be connected to a cathode of the battery, particularly via a cathode current collector. Alternatively, the first and / or second inner electrical contact member may be connected to an electronic component of an implantable medical device, e.g., an electronic circuitry. Particularly, the metal-insulator-composite assembly according to the invention may comprises more the two electrically conductive paths configured to connect more the two inner and outer electrical contact members.

[0022] Particularly, the respective layer of the multi-layer electrical insulator may be a substrate carrying conductive tracks allowing to provide electrically conducting connections between a first (e.g. top) side of the electrical insulator and an opposing second (e.g. bottom) side of the electrical insulator. Particularly, the respective layer comprises a portion of said electrically conductive first path and said second path. Particularly, the respective portion of said electrically conductive first path and said second path can comprise a conductive track and / or a via. However, electrical connections between the first outer and first inner electrical contact members and / or between the second outer and second inner electrical contact member may also be made by continuous pins as well as any other suitable structure.

[0023] According to one embodiment, the electrically insulating material is selected from a ceramic, e.g., alumina (AI2O3), a glass, or a glass-ceramic.

[0024] According to one embodiment, the electrically insulating material of the electrical insulator is a multilayer composite, e.g. one of a low temperature co-fired ceramic (LTCC), a high temperature co-fired ceramic (HTCC).

[0025] 24.055P-WO 19.11.2025Particularly, the LTCC may be primarily composed of glass and ceramic powders with glass formers, e.g., SiCL, or B2O3, glass modifiers, e.g., AI2O3, CaO, or MgO, ceramic fillers, e.g., AI2O3, ZnO, TiCL, or BaO, and various additives, and may comprise conductive paths made from a metal, e.g., silver, copper, or gold. Furthermore, the HTCC may be primarily composed of high-purity ceramic materials, e.g., AI2O3, MgO, or SiO2, with conductive paths made from refractory metals, e.g., W, Mo, or Pt, and may also comprise glass additives. Furthermore, in an embodiment, the LTCC comprises a glass former selected from the group comprised of: SiO2, B2O3. Further, in an embodiment, the LTCC comprises a glass modifier selected from the group comprised of: AI2O3, CaO, MgO. Furthermore, in one embodiment, the HTCC comprises a ceramic filler selected from the group comprised of: AI2O3, ZnO, TiO2, BaO. Particularly, in an embodiment, the LTCC comprises an additive selected from the group comprised of: PbO, Na20, K2O. Furthermore, in an embodiment, the HTCC comprises a ceramic material such as AI2O3, and may further comprise MgO and / or SiO2. Particularly, in an embodiment, the HTCC comprises refractory metals such as W, Mo, Mo-Mn, Pt. Particularly, in yet a further embodiment, the HTCC comprises glass additives selected from the group comprised of: SiCL, B2O3, AI2O3, CaO, Na20.

[0026] Particularly, multi-layer LTCC or HTCC substrates may be made by stacking multiple ceramic layers, wherein each layer can carry a printed circuit. The layers may be stacked and laminated under pressure to form a single structure. The entire stack is then co-fired causing the layers to bond. Particularly, LTCC processes are typically conducted at temperatures below 1000°C, suitable for glass-ceramic composites and low-melting-point metals. HTCC processes are typically conducted at temperatures above 1200°C.

[0027] According to a further embodiment, the electrical insulator is connected to the first flange through a solder joint or braze joint.

[0028] According to a further embodiment of the present invention, the solder is

[0029] a metallic solder having a melting temperature below 500°c, particularly an eutectic gold solder, e.g., Au80Sn20, or Ag-Sn, Au-Si, or a silver solder, e.g., Ag-Sn, a metallic solder having a melting temperature equal or above 500°C, e.g., Ti-Ni,

[0030] 24.055P-WO 19.11.2025a glass solder.

[0031] Furthermore, according to a preferred embodiment, the first flange comprises or is formed from one of the following materials: titanium (Ti), a titanium alloy, steel, particularly stainless steel, niobium (Nb).

[0032] According to one embodiment, the metal-insulator-composite assembly, particularly designed as a battery lid, comprises a second flange separate to the first flange. Particularly, in one embodiment, the electrical insulator is arranged between the first flange and the second flange. Particularly when being designed as a battery lid, such metal-ceramic-composite assembly is particularly suitable for an elongated medical implant such as an implantable cardiac monitor or an implantable leadless pacemaker, wherein the battery housing may be connected to the first flange and a further housing part of the implantable medical, e.g., accommodating an operational electronic circuitry, is connected to the second flange.

[0033] According to an alternative embodiment, the first flange is a single flange of the batter lid and comprises an opening, wherein the electrical insulator is arranged in the opening. Particularly, in one embodiment, the electrical insulator is supported on a step of the flange formed on an inside of the opening of the flange. Furthermore, according to one embodiment, the electrical insulator is flush with a circumferential face side of the flange.

[0034] According to one embodiment, the metal-insulator-composite assembly, particularly designed as a battery lid, comprises an electronic circuit that is arranged on the electrical insulator, wherein particularly the electronic circuit may also be partially or fully integrated into the electrical insulator.

[0035] In one embodiment, the electronic circuit comprises at least one of: a photodiode, a charging circuit for a rechargeable battery, a short-circuit protection, an overvoltage protection (e.g. using voltage limiters), an electrical filter (e.g. using capacitors), an RF circuit (e.g. a resonant circuit).

[0036] 24.055P-WO 19.11.2025In one embodiment, the electronic circuit comprises a sensor, particularly an optical sensor, e.g., formed by or comprising a photodiode. In one embodiment, the optical sensor is designed as an optical pulse oximetric sensor. In one embodiment, the optical sensor is arranged on the electrical insulator or is integrated in the electrical insulator, particularly such that light, e.g., infrared light, visible light, ultraviolet light, can be transmitted from an outside of the assembly or a medical device comprising the assembly to the optical sensor. For example, the optical sensor may be integrated in the electrical insulator and may be optically accessible from an outside by an optical window in the electrical insulator, e.g., formed by a transparent material, e.g., a glass.

[0037] Particularly, in one embodiment, the photodiode is configured to detect light generated upon welding a flange of the battery lid to a casing of a battery or to a further part (e.g. housing of a medical implant), wherein the electronic circuit is configured to interrupt an electrical connection (e.g. to the battery) based on a signal generated by the photodiode in response to said received light, e.g. to separate electronic components of the electronic circuit or other circuitry from a power source (e.g. from the battery associated to the battery lid).

[0038] In case a fluid-tight metal housing (e.g. out of stainless steels or titanium) is required for the implantable battery, as is usually the case for an implantable medical device, or for the implantable medical device, the (e.g. ceramic) electrical insulator is connected to the respective flange by a corresponding connection. Particularly, this may be done with a solder, particularly a solder with a low melting point (e.g. based on gold or other precious / passivating materials) as compared to solders used for brazing as described herein. However, in a sandwich structure of an electrical insulator and a flange and an intermediary solder, the differences in the coefficient of thermal expansion are typically not reduced by elastic bending, so such geometries are more sensitive. To alleviate such challenges, spacers may be used to reduce stresses caused by differences in thermal expansion coefficients between the flange (e.g. metal) and the electrical insulator (e.g. ceramic).

[0039] 24.055P-WO 19.11.2025Thus, according to one embodiment, the metal-insulator-composite assembly comprises at least one spacer arranged between the electrical insulator and the first flange, and optionally also at least one spacer arranged between the electrical insulator and the second flange (if present).

[0040] In one embodiment, the at least one spacer is a protrusion integrally connected to the electrical insulator. Alternatively, the at least one spacer is a protrusion integrally connected to the first flange (or to the second flange). Alternatively, the at least one spacer is comprised within the solder, wherein the at least one spacer has a higher melting temperature than the solder. For example, the at least one spacer may be formed by glass beads comprised within the used solder, wherein upon melting the solder in order join, e.g., the electrical insulator with the first flange, the spacer in form of glass bead remain in its solid form in order to perform its spacing function. Particularly, a plurality of spacers may be arranged between the electrical insulator and the first flange (and optionally between the electrical insulator and the second flange if present).

[0041] According to one embodiment, the at least one spacer is a component separate to the first flange (and separate to second flange) as well as separate to the electrical insulator, wherein particularly the at least one spacer comprises gold or is formed out of gold. Also, here, several separate spacers may be employed between the first flange and the electrical insulator (and between the electrical insulator and the second flange if present).

[0042] A further aspect of the present invention relates to an arrangement comprising a metallic body (particularly a first flange) and an electrical insulator comprising a ceramic material, wherein the electrical insulator is connected to the metallic body through a solder joint, the solder joint comprising a solder having a melting point below 500°C, particularly below 400°C, particularly below 350°. In a preferred embodiment of the arrangement according to the further aspect of the present invention at least one spacer (particularly a plurality of spacers) is arranged between the metallic body (e.g. flange) and the electrical insulator, wherein particularly the at least one spacer may be designed as described above in conjunction with metal-ceramic-composite assembly according to the present invention. Particularly, the arrangement or assembly may be a feedthrough, a lid, a battery lid, a

[0043] 24.055P-WO 19.11.2025structure of a medical implant. The features described herein in conjunction with the battery lid according to the present invention can each be used to further characterize the arrangement according to the present invention.

[0044] Yet another aspect of the present invention relates to a battery (particularly for a medical implant), the battery comprising a metal-ceramic-composite assembly, particularly designed as a battery lid, according to the present invention.

[0045] A further aspect of the present invention relates to medical implant, comprising a metal-ceramic-composite assembly, particularly designed as a battery lid, according to the present invention or a battery according to the present invention, or an arrangement according to the present invention.

[0046] In the following, embodiments of the present invention as well as further features and advantages of the present invention shall be described with reference to the Figures, wherein

[0047] Fig. 1 shows a schematic cross section of an embodiment of an assembly designed as battery lid according to the present invention, wherein assembly comprises an electrical insulator arranged between two opposing flanges,

[0048] Fig. 2 shows a schematic cross section of a further embodiment of an assembly designed as a battery lid according to the present invention, wherein the assembly comprises an electrical insulator arranged in an opening of a single flange,

[0049] Fig. 3 shows a schematic cross section of a modification of the embodiment shown in Fig. 2,

[0050] Fig. 4 shows a schematic cross section of an embodiment of an arrangement or assembly according to the present invention comprising an electrical insulator and a metallic body such as a flange,

[0051] 24.055P-WO 19.11.2025Fig. 5 shows a schematic cross section of an embodiment of an arrangement or assembly according to the present invention comprising an electrical insulator arranged between two opposing metallic bodies (e.g. flanges),

[0052] Fig. 6 shows a schematic cross section of an embodiment of an arrangement or assembly according to the present invention comprising a metallic body (e.g. a flange) connected to an electrical insulator, the electrical insulator comprising integrated electrically conductive paths,

[0053] Fig. 7 shows a schematic cross section of an embodiment of an arrangement or assembly according to the present invention comprising a metallic body (e.g. a flange) connected to an electrical insulator, the electrical insulator comprising integrated electrically conductive paths as well as electronic components arranged on the electrical insulator and / or integrated into the electrical insulator,

[0054] Fig. 8 shows a schematic cross section of an embodiment of an arrangement or assembly according to the present invention comprising a metallic body (e.g. a flange) connected to an electrical insulator, the electrical insulator comprising integrated electrically conductive paths as well as electronic components encapsulated by the electrical insulator,

[0055] Fig. 9 shows a schematic cross section of an embodiment of an arrangement or assembly designed as a battery lid according to the present invention comprising an electrical insulator and a metallic body (such as a flange) as well as spacers integrally connected to the electrical insulator,

[0056] Fig. 10 shows a schematic cross section of an embodiment of an arrangement or an assembly designed as a battery lid according to the present invention comprising an electrical insulator and a metallic body (such as a flange) as well as spacers integrally connected to the metallic body, and

[0057] 24.055P-WO 19.11.2025Fig. H shows a schematic cross section of an embodiment of an arrangement or an assembly designed as a battery lid according to the present invention comprising an electrical insulator and a metallic body (such as a flange) as well as separate spacers arranged between the metallic body and the electrical insulator.

[0058] Fig. 1 shows a schematic cross section of an embodiment of an assembly according to the present invention being designed as a battery lid 1. The battery lid 1 comprises a first metallic flange 2 that may be made out of titanium or steel, particularly stainless steel. The battery lid 1 further comprises an electrical insulator 3 comprising a ceramic material, wherein the electrical insulator 3 comprises a first (e.g. top) side 3a and a second (e.g. bottom) side 3b and is connected to the first flange 2 through a solder joint 4, wherein the solder joint 4 comprises a solder having a melting point below 500°C, preferably below 400°C, more preferably below 350°C. Particularly, the solder joint 4 is a circumferential solder joint 4 connecting the flange 2 to a circumferential boundary region of the second side 3b of the electrical insulator.

[0059] Furthermore, particularly, the battery lid 1 may comprise a second flange 20 opposing the first flange 2, wherein the electrical insulator 3 is arranged between the opposing flanges 2, 20. The electrical insulator 3 is also connected to the second flange 20 through a further solder joint 40, wherein the further solder joint 40 also comprises a solder having a melting point below 500°C, preferably below 400°C, more preferably below 350°C. Particularly, the further solder joint 40 is a circumferential solder joint 40, too, connecting the further flange 20 to a circumferential boundary region of the first side 3 a of the electrical insulator 3.

[0060] Particularly, the respective flange 2, 20 may be soldered onto the electrical insulator 3 with a solder such as e.g. Au80Sn20. In this case, the soldering temperature would be around 300°C. Alternatively, specially alloyed active solders can also be used. Ultrasonic soldering processes using special solders can also be used for soldering the flanges 2, 20 to the electrical conductor 3.

[0061] 24.055P-WO 19.11.2025Further, the flanges 2, 20 may be annular flanges 2, 20 that can comprise a step 2a, 20a on an outer periphery, respectively, so that the first flange 2 may accommodate a face side of a battery housing (not shown) and the second flange 20 may accommodate a face side of a further housing part (not shown), e.g., of a medical implant. Battery lids 1 of the type shown in Fig. 1 are therefore particularly suitable for e.g. medical implants with elongated (e.g. cylindrical) housings such as implantable cardiac monitoring devices, implantable sensors, and implantable leadless pacemakers.

[0062] Particularly, for use in current batteries with housings made of stainless steel or titanium, it is beneficial to use materials of the same type or welding-compatible materials as flanges 2, 20. If necessary, these are coated so that they may be soldered. Particularly, the electrical insulator 3 may be coated with solderable areas, too, as is common with substrates that carry conductors.

[0063] For example, as described herein, in certain preferred embodiments, a LTCC (low temperature co-fired ceramic) or a HTCC (high temperature co-fired ceramic) or another suitable material is used as material for the electrical insulator 3 shown in Fig. 1 that carries the outer electrical contacts members 60, 70 of the battery lid 1. Particularly, a compact or multi-layer ceramic (e.g. HTCC or LTCC), as used in the manufacture of circuit or chip carriers, is used as electric insulator 3 and sealing element of the battery lid 1. In case of a multi-layer electrical insulator 3 the latter comprises a plurality of layers stacked on top of one another, wherein each layer may carry conductive paths / tracks. However, the electrical insulator 3 may also be manufactured out of a ceramic, a glass, a glass ceramic, a plastic material in alternative embodiments.

[0064] Particularly, a multi-layer electrical insulator 3 / circuit carrier offers the possibility of routing conductive paths in inner layers, which enables the integration of passive and active components for providing smart components in / on the battery lid 1. The use of through-hole technology (vias) enables advantageous connection geometries. This enables better volume utilization (capacity per volume).

[0065] 24.055P-WO 19.11.2025Furthermore, the low melting point of the solder used for creating the mechanical connection 4, 40 between the flange(s) 2, 20 and the electrical insulator 3, and to ensure fluid-tightness, enables the process to be carried out without special protective measures (e.g. soldering under vacuum). In special cases (process temperature <400°C for titanium) the soldering process may be carried out completely without protective measures (soldering in atmosphere), enabling the use of continuous furnaces as with SMT lines (standard technology). Furthermore, the planar / stacked structure shown in Fig. 1 for example is particularly advantageous because it is easy to assemble.

[0066] As further indicated in Fig. 1, the electrical insulator 3 may extend over the majority of the cross-section of the battery casing or over the complete cross-section of the battery casing and flanges 2, 20 of relatively small radial thickness suffice to realize the battery lid 1.

[0067] Furthermore, as shown in Fig. 1, the battery lid 1 comprises a first and a second outer electrical contact member 60, 70 arranged on the first side 3a of the electrical insulator 3 as well as first and a second inner electrical contact member 61, 71 arranged on the second side 3b of the electrical insulator 3, the second side 3b facing away from the first side 3a. Particularly, the first electrical outer contact member 60 is electrically connectable to the first electrical inner contact member 61 via an electrically conductive first path 62 integrated into the electrical insulator 3, and the second electrical outer contact member 70 is electrically connectable to the second electrical inner contact member 71 via an electrically conductive second path 72.

[0068] Further, the battery lid 1 may comprise an electronic circuit 5 that is arranged on the electrical insulator 3. Particularly, said paths 62, 72 may be routed via the electronic circuit 5. In some embodiments, the electronic circuit 5 may comprise at least one of: a photodiode, a charging circuit for a rechargeable battery, a short-circuit protection, an overvoltage protection, an electrical filter, an RF circuit. Particularly, the photodiode may be used to detect light generated upon welding a flange 2, 20 of the battery lid 1 to a housing of a battery or to a further part (e.g. housing of a medical implant), wherein the electronic circuit 5 is configured to interrupt an electrical connection (e.g. to the battery via paths 62, 72) based on a signal generated by the photodiode in response to said detected

[0069] 24.055P-WO 19.11.2025light, e.g. to separate electronic components of the electronic circuit 5 or other circuitry from the battery.

[0070] Fig. 2 shows a modification of the embodiment shown in Fig. 1, wherein in contrast to Fig.

[0071] 1 a single annular flange 2 is used, the flange 2 comprising a through opening 2b in which the electrical insulator 3 is accommodated. Particularly, the electrical insulator 3 may be connected via a solder joint 4 to a step 2c formed on an inner side of the flange 2 that delimits the opening 2b. Particularly, as indicated in Fig. 2, the electrical insulator 3 may be flush with a circumferential face side of the flange 2. In this respect, Fig. 3 shows a further modification of the embodiment shown in Fig. 2, wherein here the electrical insulator 3 is not arranged flush with said face side but is inserted into the opening 2b such that the flange 2 extends past the first and second side 3a, 3b of the electrical insulator 3 along an axis of the flange 2 extending perpendicular to said first and second sides 3 a, 3b.

[0072] Furthermore, in the embodiments shown in Figs. 1 to 3, one or several spacers 6 arranged between the electrical insulator 3 and the respective flange 2, 20, as indicated in Figs. 9 to 11, can be used to reduce stresses caused by differences in the thermal expansion coefficients between metal and ceramic materials used for the flange(s) 2, 20 and the electrical insulator 3. Particularly, as shown in Fig. 9 the respective spacer 6 may be a protrusion integrally connected to the electrical insulator 3. Alternatively, as shown in Fig.

[0073] 10, the respective spacer 6 may be a protrusion integrally connected to the respective flange 2, 20. Furthermore, alternatively, as shown in Fig. 11, the respective spacer 6 may be a separate component being arranged between the respective flange 2, 20 and the electrical insulator 3. Particularly, the separate spacers 6 can be formed out of gold. Particularly, this is a material component of the used solder alloy. This ensures that the respective spacer 6 is still in solid form at the solder temperature and may therefore fulfill its function and, on the other hand, no additional foreign component such as glass is inserted into the solder layer, which leads to brittle phases. Advantageously, the gold spacer(s) 6 may be inserted automatically using a bonder.

[0074] Particularly, the battery lid 1 according to the afore-described embodiment offers the advantages of a simple assembly using standard materials, wherein particularly a single-

[0075] 24.055P-WO 19.11.2025axis assembly or automated assembly is possible due to the sandwich structure. Furthermore, particularly, no complex chamber process is needed to connect the flange(s) to the electrical insulator and SMT soldering to atmosphere is possible due to low joining temperatures. Furthermore, the electrical insulator according to the present invention enables integration of passive and active components and mapping of smart functions. Furthermore, particularly, battery volume may be saved owing to the design of the battery lid according to the present invention with at least identical battery capacity.

[0076] In the above, the present invention has been described with respect to a battery lid 1. However, the present invention can be applied to general arrangements or assemblies 1 comprising an electrical insulator 3 and a metallic body 2 (e.g. a flange) as shown in Fig. 4, which are connected by a solder joint 4 using a solder having a melting temperature below 500 °C, particularly below 400°C, particularly below 350 °C. Particularly, the electrical insulator 3 comprises a ceramic material, and preferably is a multi-layer electrical insulator 3 comprising a plurality of layers stacked on top of one another. Preferably, as described above, the ceramic material is one of: a low temperature co-fired ceramic (LTCC), a high temperature co-fired ceramic (HTCC).

[0077] Such metal-ceramic composites are often difficult to produce because differences in the thermal expansion coefficients of the materials during the joining processes (usually high-temperature soldering processes) cause stresses in the cooling process after the solder has solidified, which usually lead to cracks in the ceramic. This occurs in particular when tensile or mixed stresses arise in the ceramic due to the geometric conditions. However, due to the selection of materials, particularly for the electrical insulator 3 and the solder joint 4, particularly low temperature soft solders, automated production is enabled. Furthermore, by using ceramics, as they are particularly also used to manufacture printed circuit boards, smart functions can be integrated by integrating passive and active electronic components (e.g. overvoltage protection) as describe above. In this fashion, arrangements or assemblies in form of vacuum-tight metal / glass / ceramic composites may be manufactured that can be produced automatically with or without through-hole plating and optional integration of smart functions. Such arrangements or assemblies may be used as feedthroughs, battery lids etc.

[0078] 24.055P-WO 19.11.2025Particularly, Fig. 5 shows a further embodiment of an arrangement or assembly according to the present invention comprising an electrical insulator 3 arranged between two opposing metallic (e.g. titanium or steel) bodies (e.g. flanges) 2, 20, wherein the respective solder joint 4, 40 connecting the electrical insulator 3 to the respective metal body 2, 20 comprises a solder having a melting temperature below 500 °C, particularly below 400°C, particularly below 350 °C (e.g. Au80Sn20). Particularly, the arrangement or assembly 1 may be used as a feedthrough, a battery lid and the like.

[0079] Furthermore, Fig. 6 shows a schematic cross section of a modification of the embodiment shown in Fig. 4, wherein the electrical insulator 3 comprises integrated electrically conductive paths 7.

[0080] Further, Fig. 7 shows a schematic cross section of a modification of the embodiment shown in Fig. 6, wherein in addition to the integrated conductive paths 7, the arrangement or assembly 1 comprises at least one inner electronic component 8 (e.g. a resistor) embedded in the electrical insulator 3 as well as at least one outer electronic component 9 (e.g. a voltage limiter) arranged on an outside of the electrical insulator 3. Particularly, the respective electronic component 8, 9 is connected to conductive paths 7 integrated into the electrical insulator 3.

[0081] Furthermore, Fig. 8 shows a schematic cross section of a modification of the embodiment shown in Fig. 7, wherein the electronic components 8, 9 are both accommodated in a cavity 30 formed by the electrical insulator 3. Also, here, the electronic components 8, 9 are connected to conductive paths 7 integrated in the electrical insulator 3.

[0082] Furthermore, the spacers 6 shown in Figs. 9 to 11 may also be used in the arrangements or assemblies 1 shown in Fig. 4 to 8. Particularly, the respective spacer 6 may be arranged between the electrical insulator 3 and the opposing metal body (e.g. flange) 2, 20.

[0083] With regard to the respective arrangement 1 shown in Figs. 4 to 11, the invention can simplify the structure and the manufacturing process (e.g. planar structures, sandwich

[0084] 24.055P-WO 19.11.2025structure without steps, undercuts, etc.). Due to the specific design, the components required for the assemblies can be assembled automatically in a single-axis assembly and soldered in continuous furnaces in a similar way to SMT processes, in particularly favorable cases without an inert gas atmosphere. By selecting certain eutectic solders, e.g. gold-based (or other biostable / biocompatible solders with corresponding melting temperatures or solidus temperatures below 500 °C, particularly below 400 °C, particularly below 350 °C), less temperature-stable materials can be used (e.g. LTCC) and mechanical stresses as a result of thermal expansion coefficient differences can also be reduced with temperature-stable materials. This enables the use of metals with higher coefficients of thermal expansion.

[0085] Due to the lower melting point of the solder for creating the mechanical connection and ensuring fluid-tightness, the process can be carried out without special protective measures (e.g. soldering under vacuum). In special cases (process temperature <400°C), even with titanium (soldering in atmosphere), soldering is possible without any protective measures, allowing the use of continuous furnaces as with SMT lines (standard technology).

[0086] 24.055P-WO 19.11.2025

Claims

Claims1. A (metal-ceramic-composite) assembly (1) particularly for an implantable battery or an implantable medical device, comprising:- a first metallic flange (2),- an electrical insulator (3) comprising an electrically insulating material, whereinat least one spacer (6) arranged between the electrical insulator (3) and the first flange (2).

2. The assembly (1) according to claim 1, wherein the electrical insulator (3) is a multilayer electrical insulator (3) comprising a plurality of electrically insulating layers stacked on top of one another.

3. The assembly (1) according to claim 1 or 2, wherein the electrically insulating material is selected from: a ceramic (A12O3), a glass, or a glass-ceramic, particularly a low temperature co-fired ceramic (LTCC), a high temperature co-fired ceramic (HTCC),.

4. The assembly according to one of the preceding claims, wherein the electrical insulator (3) is connected to the first flange (2) through a solder or braze joint (4).

5. The assembly (1) according to claim 4, wherein the solder is- a metallic solder having a melting point below 500°C, particularly an eutectic gold solder, e.g., Au80Sn20, or Au-Si, or a silver solder, e.g., Ag-Sn, - a metallic solder having a melding point equal of above 500°C, particularly a nickel -titanium solder, or- a glass solder.

6. The assembly (1) according to one of the preceding claims, wherein the at least one spacer (6) is a protrusion integrally connected to the electrical insulator (3), or wherein the at least one spacer (6) is a protrusion integrally connected to the flange24.055P-WO 19.11.2025(2), or wherein the at least one spacer (6) is a component separate to the flange (2) and the electrical insulator (3).

7. The assembly (1) according to one of the preceding claims, wherein the flange (2) comprises or is formed from one of the following materials: titanium (Ti), a titanium alloy, stainless steel, niobium (Nb)8. The assembly (1) according to one of the preceding claims, further comprising a second flange (20) separate to the first flange (2).

9. The assembly (1) according to claim 7, wherein the electrical insulator (3) is arranged between the first flange (2) and the second flange (2).

10. The assembly (1) according to one of the claims 1 to 6, wherein the first flange (2) comprises an opening (2b), wherein the insulator (3) is arranged in the opening (2b).

11. The assembly (l)according to one of the preceding claims, wherein the metalceramic assembly (1) comprises a first outer electrical contact member (60) and a second outer electrical contact member (70) arranged on a first side (3a) of the electrical insulator (3) as well as first and a second inner electrical contact member (61, 71) arranged on a second side (3b) of the electrical insulator, the second side (3b) facing away from the first side (3a), the first electrical outer contact member being electrically connectable to the first electrical inner contact member via an electrically conductive first path (62) integrated into the electrical insulator (3), and the second electrical outer contact member (70) being electrically connectable to the second electrical inner contact member (71) via an electrically conductive second path (72).

12. The assembly (1) according to one of the preceding claims, further comprising an electronic circuit (5) that is arranged on or integrated within the electrical insulator (3).24.055P-WO 19.11.202513. The assembly (1) according to claim 12, wherein the electronic circuit (5) comprises at least one of: a photodiode, a charging circuit for a rechargeable battery, a short- circuit protection, an overvoltage protection, an electrical filter, an RF circuit.

14. A battery, particularly for a medical implant, the battery comprising an assembly (1) (1) according to one of the preceding claims, the assembly (1) being particularly designed as a battery lid.

15. A medical implant comprising- an assembly (1) according to one of the claims 1 to 13, wherein the assembly (1) is particularly designed as an electrical feedthrough, or- a battery according to claim 14.24.055P-WO 19.11.2025

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