EP2810311A2

EP2810311A2 - Thermoelectric generator module, metal-ceramic substrate and method for producing such a metal-ceramic substrate

Info

Publication number: EP2810311A2
Application number: EP13705093.6A
Authority: EP
Inventors: Andreas Meyer; Jürgen SCHULZ-HARDER
Original assignee: Curamik Electronics GmbH
Current assignee: Rogers Germany GmbH
Priority date: 2012-01-31
Filing date: 2013-01-22
Publication date: 2014-12-10
Also published as: US20140345664A1; WO2013113311A4; WO2013113311A2; DE102012102090A1; JP2015511397A; KR20140123484A; CN104106153A; WO2013113311A3

Abstract

The invention relates to a thermoelectric generator module with a hot zone (1a) and a cold zone (1b) comprising at least a first metal-ceramic substrate (2), which has a first ceramic layer (6) and at least one structured first metallization (4) applied to the first ceramic layer (6) and is assigned to the hot zone, and at least a second metal-ceramic substrate (4), which has a second ceramic layer (7) and at least one structured second metallization (5) applied to the second ceramic layer and is assigned to the cold zone (1b), and also a number of thermoelectric generator components (N, P) located between the first and second structured metallizations (4, 5) of the metal-ceramic substrates (2, 3). Particularly advantageously, the first metal-ceramic substrate (2), assigned to the hot zone (1a), has at least one layer of steel or high-grade steel (8), wherein the first ceramic layer (6) is arranged between the first structured metallization (4) and the at least one layer of steel or high-grade steel (8). The invention also relates to an associated metal-ceramic substrate and to a method for producing it.

Description

The invention relates to a thermoelectric generator module according to the preamble of claim 1, an associated metal-ceramic substrate according to the preamble of claim 24 and a method for producing a metal-ceramic substrate according to the preamble of claim 34. The operation of thermoelectric generators is known in principle. By means of a between the hot and cold area of a thermoelectric

Generator component existing temperature difference, a heat flow is generated, which is converted via the thermoelectric generator component into electrical energy. For this purpose, thermoelectric generator components produced from a thermoelectric semiconductor material are preferably used.

Currently, the use of thermoelectric generators for direct

Conversion of heat into electrical energy in the automotive field is examined, for example, from the residual heat of the exhaust gases electrical energy for the

regain in-vehicle energy system. According to initial findings, this could significantly reduce the fuel consumption of the vehicle.

The problem here, however, is the arrangement of such a

thermoelectric semiconductor components produced thermoelectric generator components in the exhaust system of the vehicle, especially in the field of exhaust system. For this purpose, thermoelectric generators or thermoelectric generator modules with a high temperature change resistance are required, in particular

Temperature fluctuations between 40 ° C and 800 ° C in the exhaust or hot area reliably withstand. Furthermore, metal-ceramic substrates, preferably in the form of printed circuit boards in various designs are known which, for example, at least one

Ceramic layer and at least one on one of the surface sides of

Have ceramic layer applied metallization, wherein the metallization is structured to form interconnects, contact or mounting areas.

Also known, for example, is the so-called "DCB process" ("direct copper bonding") for joining metal layers or sheets, preferably

Copper sheets or foils with each other and / or ceramic or ceramic layers, using metal or copper sheets or metal or

Copper foils having on their surface sides a layer or a coating

("Aufschmelzschicht") of a chemical compound of the metal and a reactive gas, preferably oxygen.This example, in US-PS 37 44 120 or in DE-PS 23 1 9 854 described method forms this layer or coating ("Aufschmelzschicht") a eutectic with a

Melting temperature below the melting temperature of the metal (e.g., copper), so that by laying the metal or copper foil on the ceramic and by heating all the layers can be joined together by melting the metal or copper substantially only in the region

Melting layer or oxide layer. Such a DCB method then has, for example, the following method steps:

Oxidizing a copper foil such that a uniform

Copper oxide layer results;

- Laying the copper foil with the uniform copper oxide layer on the

Ceramic layer;

Heating the composite to a process temperature between about 1025 to 1083 ° C, for example to about 1071 ° C;

Cool to room temperature. Furthermore, DE 2213115 and EP-A-153618 disclose the so-called active soldering method for joining metal layers or metal foils forming metallizations, in particular also copper layers or copper foils with a ceramic material or a ceramic layer. In this method, which is also used especially for the production of metal-ceramic substrates, at a temperature between about 800 - 1000 ° C, a connection between a

Metal foil, such as copper foil, and a ceramic substrate, such as an aluminum nitride ceramic, prepared using a brazing filler, which also contains an active metal in addition to a main component, such as copper, silver and / or gold. This active metal, which is, for example, at least one element of the group Hf, Ti, Zr, Nb, Ce, establishes a bond between the braze and the ceramic by a chemical reaction, while the bond between the braze and the metal forms a metallic braze joint is. Also thermoelectric generator components in the form of so-called Peltier elements are known, which produce a current difference in the flow of a temperature difference or a current flow in the presence of temperature difference. Such a Peltier element essentially comprises two parallelepipedic semiconductor elements which have a different energy level, i. are formed either p- or n-type, which are connected by a metal bridge on one side. At the same time, the metal bridges also form the thermal connection surface, which is preferably applied to a ceramic and thus insulated from one another. Thus, in each case a p- and n-conducting cuboid semiconductor element via a

Metal bridge connected together, in such a way that a series connection of the Peltier elements is formed.

Based on the above-mentioned prior art, the present invention seeks to provide a thermoelectric generator module and an associated metal-ceramic substrate and a method for its production, which has a high thermal shock resistance, in particular an arrangement of thermoelectric generator components in the exhaust gas of a Motor vehicle allows. To solve this problem, a thermoelectric generator module according to claim 1 is formed. An associated metal-ceramic substrate and a method for its manufacture are the subject of claim 24 and 34.

The essential aspect of the inventive thermoelectric generator module having a hot and cold region comprising at least a first, the hot region associated metal-ceramic substrate having a first ceramic layer and at least a first applied to the first ceramic layer, structured metallization and at least a second, the cold area associated Metal-ceramic substrate having a second ceramic layer and at least a second on the second

Ceramic layer applied, structured metallization and a plurality of recorded between the first and second patterned metallization of the metal-ceramic substrates thermoelectric generator components u.a. in that the first metal-ceramic substrate assigned to the hot region has at least one steel or stainless-steel layer, wherein the first ceramic layer is arranged between the first structured metallization and the at least one steel or stainless-steel layer. It is particularly advantageous by means of the hot region of the

According to the invention provided for thermoelectric generator module steel or stainless steel layer a simple and reliable connection of the module in

Exhaust portion of a motor vehicle, in particular on or in the region of the exhaust system of a motor vehicle allows. For example, a direct connection of the module on the steel or stainless steel layer on the exhaust of a motor vehicle.

In one development of the invention, the thermoelectric generator module according to the invention is designed, for example, in such a way that

that between the first ceramic layer and the at least one steel or

Stainless steel layer is provided at least one copper layer,

and or in that the second metal-ceramic substrate assigned to the cold region has at least one corrosion-resistant metal layer, the second ceramic layer being arranged between the second structured metallization and the corrosion-resistant metal layer,

and or

that the corrosion-resistant metal layer by a stainless steel, aluminum or

Copper layer is formed,

and or

the first and second metallizations are structured such that they form a plurality of metallic contact surfaces, which are preferably rectangular and / or square-shaped,

that the longitudinal sides of a rectangular, metallic contact surface

approximately twice as long as their broadsides,

and or

that the longitudinal sides of the rectangular, metallic contact surfaces extend parallel to the module transverse axis and the broad sides of the rectangular, metallic contact surfaces extend parallel to the module longitudinal axis,

and or

that the longitudinal sides are between 0.5 mm and 10 mm and the broad sides between 0.2 mm and 5 mm,

and or

that the metallic contact surfaces are arranged in a matrix-like manner on the surface side of the respective ceramic layer,

and or

that the rectangular, metallic contact surfaces parallel to the module longitudinal axis extending rows and parallel to the module transverse axis extending columns, and / or

that two adjacent rectangular, metallic contact surfaces have a distance of 0.1 mm to 2 mm in the direction of the module transverse axis,

and or that two adjacent rectangular, metallic contact surfaces in the direction of the module longitudinal axis have a distance of 0.1 mm to 2 mm,

wherein the aforementioned features can be used individually or in any combination.

In an advantageous embodiment variant of the thermoelectric generator module according to the invention, preferably rectangular metallic ones are arranged between the spaced-apart ones arranged on the respective ceramic layer

Contact surfaces separating or predetermined breaking lines introduced into the ceramic layer, which preferably in the direction of the module transverse axis and / or in the direction of

Module longitudinal axis run. These can advantageously be realized in the form of slots, notches and / or points, wherein the depth of the slots, notches and / or points of a separation or break line starting from the metallization receiving surface side of a ceramic layer is at least over a quarter of

Layer thickness of the respective ceramic layer extends. Can be particularly advantageous by introducing separation or predetermined breaking lines by high

Temperature fluctuations caused material fractures in the ceramic are controlled intercepted, so that even if the ceramic layer breaks the

Operation of the thermoelectric generator module is still guaranteed.

the ceramic layer is made of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide and preferably has a layer thickness in the range between 0.1 mm and 1.0 mm,

and or

the first and second structured metallization are in the form of metal layers or metal foils, preferably made of copper or a copper alloy, which preferably have a layer thickness in the range between 0.03 mm and 1.5 mm,

and or that the metallizations at least partially with a metallic

Surface layer are provided, for example, a surface layer of nickel, silver or a nickel or silver alloy,

and or

in that the thermoelectric generator components are in the form of Peltier elements produced from a differently doped semiconductor material, the layer thickness of the semiconductor material preferably being between 0.5 mm and 8 mm, wherein the aforementioned features can be used individually or in any desired combination.

In a further advantageous embodiment of the thermoelectric

Generator module, the thermal conductivity and reliability is improved by that

the steel or stainless steel layer and / or the corrosion-resistant metal layer is formed in several parts, wherein at least two parts of the steel or stainless steel layer and / or the corrosion-resistant metal layer are arranged spaced from each other such that at least one externally freely accessible surface portion of the ceramic layer is formed and / or

that the steel or stainless steel layer and / or the corrosion-resistant metal layer is formed structured or profiled and / or

the steel or stainless steel layer and / or the corrosion-resistant metal layer have an encircling bead in a region projecting outward beyond the edge region of the ceramic layer,

wherein the aforementioned features may in turn be used individually or in any combination.

The invention further provides a metal-ceramic substrate for use in a thermoelectric generator module comprising at least one ceramic layer and at least one structured layer applied to the ceramic layer

Metallization, in the particularly advantageous at least one steel or Stainless steel layer is provided, wherein the ceramic layer between the structured metallization and the at least one steel or stainless steel layer is arranged.

In an advantageous development, the metal-ceramic substrate is for example designed such

in that at least one copper layer is provided between the ceramic layer and the at least one steel or stainless steel layer,

and or

that the metallization is structured in such a way that it has several metallic ones

Forms contact surfaces, which are preferably rectangular in shape and are spaced from each other,

and or

that the longitudinal sides of a rectangular, metallic contact surface

are approximately twice as long as their broad sides, wherein the longitudinal sides are preferably between 0.5 mm and 10 mm and the broad sides between 0.2 mm and 5 mm,

and or

the metallic contact surfaces are like a matrix on the surface side of the

Ceramic layer are arranged, in rows and columns,

and or

separating or predetermined breaking lines are introduced into the ceramic layer between the metallic contact surfaces, which are preferably realized in the form of slots, notches and / or points,

and or

in that the slots, notches and / or points of a breaking line, starting from the metallization-receiving surface side of a ceramic layer, extend over at least a quarter of the layer thickness of the ceramic layer,

and or

the ceramic layer of aluminum oxide, aluminum nitride, silicon nitride or

Alumina is prepared with zirconium oxide and preferably has a layer thickness in the range between 0.1 mm and 1.0 mm, and or

in that the structured metallization is in the form of a metal layer or metal foil, preferably made of copper or a copper alloy, which preferably has a layer thickness in the range between 0.03 mm and 1.5 mm, and / or

that the metallization is at least partially provided with a metallic surface layer, for example a surface layer of nickel, silver or a nickel or silver alloys,

The invention likewise provides a method for producing a metal-ceramic substrate, in particular in the form of a printed circuit board for a thermoelectric generator module, comprising at least one ceramic layer and at least one structured metallization applied to the ceramic layer, in which case directly on the surface opposite the ceramic layer or indirectly at least one steel or stainless steel layer is applied.

The method according to the invention is designed, for example,

the metallization is structured in such a way that a plurality of rectangular, metallic contact surfaces are formed, which are preferably in the form of a matrix on the

Ceramic layer are arranged,

and or

that between the rectangular, metallic contact surfaces separating or predetermined breaking lines are introduced into the ceramic layer by means of laser treatment or sawing, preferably in the form of slots, notches and / or points, and / or

the ceramic layer of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide is connected to zirconium oxide and the metallization consisting of a copper layer or copper alloy is connected by DCB bonding,

and or that the steel or stainless steel layer is bonded directly to the ceramic layer by brazing, active soldering or gluing,

The expressions "approximately", "substantially" or "approximately" in the context of the invention mean deviations from the respective exact value by +/- 10%, preferably by +/- 5% and / or deviations in the form of changes insignificant for the function ,

Further developments, advantages and applications of the invention will become apparent from the following description of exemplary embodiments and from the figures. In this case, all described and / or illustrated features alone or in any combination, in principle, the subject of the invention, regardless of their summary in the claims or their

Dependency. Also, the content of the claims is made an integral part of the description.

The invention will be explained in more detail below with reference to the figures of exemplary embodiments. Show it:

A simplified sectional view of an inventive

thermoelectric generator module, Figure 2 is a simplified representation of a plan view of the structured

Metallization of the hot side associated metal-ceramic substrate,

3 is a simplified sectional view of an alternative embodiment of the thermoelectric generator module according to Figure 1, Fig. 4 is a simplified Schnittdarstel development of another alternative

Embodiment variant of the thermoelectric generator module according to Figure 3, Fig. 5 is a simplified Schnittdarstel development of a thermoelectric

Generator module comprising two metal l ceramic substrate arrangements according to Figure 1, a simplified Schnittdarstel development of a thermoelectric

Generator module comprising a stack of two metal I ceramic substrate arrangements according to Figure 1,

Fig. 7 is a simplified Schnittdarstel development of a thermoelectric

A generator module comprising an alternative embodiment of a two metal-ceramic substrate arrangements according to FIG. 6,

Fig. 8 is a simplified Schnittdarstel development of a thermoelectric

Generator module relating to an alternative embodiment of the thermoelectric generator module according to Figure 3,

Fig. 9 is a simplified Schnittdarstel development of a thermoelectric

Generator module with a structured steel or stainless steel layer and / or corrosion-resistant metal lschicht, Fig. 1 0 is a schematic plan view of a lattice-like formed steel or

Stainless steel layer or corrosion-resistant metal layer with various lattice patterns,

Fig. 1 1 is a simplified Schnittdarstel development of a thermoelectric

Generator module concerning an alternative embodiment of the thermoelectric generator module according to Figure 1 and 12 shows a simplified sectional illustration of a thermoelectric generator module relating to an alternative embodiment of the thermoelectric generator module according to FIG

Bead.

1 shows a simplified representation of a section through a thermoelectric generator module 1 according to the invention with a hot region 1a and a cold region 1b, which essentially comprises two, preferably plate-shaped, metal-ceramic substrates 2, 3, each of which has a structured surface on its opposite surfaces Metallization 4, 5 are provided. When using the thermoelectric generator module 1 according to the invention in the automotive sector, the hot region 1a temperature fluctuations between 40 ° C and 800 ° C and the cold region 1 b between 40 ° C and 125 ° C be exposed.

The structured metallizations 4, 5 each form a plurality of preferably opposite contact surfaces 4 ', 5', the structured metallizations 4, 5 having, for example, a layer thickness between 0.03 mm and 0.6 mm. Between the opposing structured metallizations 4, 5 of the metal-ceramic substrates 2, 3 are each differently doped thermoelectric

Generator components N, P, namely, in each case a thermoelectric generator component N, P with a contact surface 4 'of the first structured metallization 4 and a portion of the opposite contact surface 5' of the second

structured metallization 5 thermally and electrically conductively connected. The thermoelectric generator components N, P are in this case preferably connected in series and made of a thermoelectric semiconductor material, i. realized in the form of Peltier elements, which each comprise an n-doped semiconductor element N and a p-doped semiconductor element P. As p- and n-doped

Semiconductor material can be used for example bismuth telluride or silicon germanium or manganese silicon. Also, the use of materials based on the chemical compounds PbTe, SnTe, ZnSb or families of skutterudites, clathrates and / or chalcogenides possible. The thickness of the semiconductor element N, P is for example between 0.5 mm and 8 mm.

To generate electrical energy of the hot region 1 a of

thermoelectric generator module 1 with a heat source and the cold region 1 b of the thermoelectric generator module 1 with a cooling source brought in heat-conducting connection, so that sets a temperature difference between the opposite hot and cold area 1 a, 1 b. When using the

thermoelectric generator module 1, the hot region 1a is arranged for example in the exhaust gas region of the motor vehicle, preferably connected directly or indirectly with the exhaust system of the motor vehicle thermally conductive. The cold region 1 b is preferably cooled and for this purpose, for example, in the coolant circuit of the

Motor vehicle with integrated. Due to the temperature difference between the hot and cold region 1a, 1b, a heat flow through the thermoelectric generator module 1, which is converted by means of the thermoelectric generator components N, P into electrical energy. In the present exemplary embodiment according to FIGS. 1 and 3, at least a first metal-ceramic substrate 2 assigned to the hot region 1a and a second metal-ceramic substrate 3 assigned to the cold region 1b are provided. However, the invention is in no way limited to two metal-ceramic substrates 2, 3 per thermoelectric generator module 1. Rather, an inventive

thermoelectric generator module 1 also comprise a plurality of such metal-ceramic substrate arrangements, also in a stacked form.

In the present exemplary embodiment, the first metal-ceramic substrate 2 has at least one first ceramic layer 6, on the surface side 6 'of which the first structured metallization 4 is applied. Analogously, the second metal-ceramic substrate 3 comprises at least one second ceramic layer 7, on the surface side thereof 7 ', the second structured metallization 5 is applied. The layer thickness of the first and second ceramic layer 6, 7 are between 0.1 mm and 1 mm, preferably between 0.3 and 0.4 mm. According to the invention, the first metal-ceramic substrate 2 assigned to the hot region 1 a has at least one steel or stainless-steel layer 8, the first one being a metal-ceramic substrate 2

Ceramic layer 6 between the first structured metallization 4 and the at least one steel or stainless steel layer 8 is arranged. In a preferred embodiment, the at least one steel or

Stainless steel layer 8 is provided for heat-conducting connection with a further metallic component, for example the exhaust of a vehicle. For a simplified attachment, the at least one steel or stainless steel layer 8 according to FIG. 3 can project at least in sections beyond the edge of the first ceramic layer 6, and thus a fastening region for producing a solder or

Form weld and / or a detachable connection.

In a preferred embodiment according to the figures 1 and 3 is the

at least one steel or stainless steel layer 8 is applied directly to the first structured metallization 4 opposite surface side 6 "of the first ceramic layer 6, by means of brazing, active soldering or gluing.

In an alternative embodiment according to Figure 4, between the first ceramic layer 6 and the at least one steel or stainless steel layer 8 a

Copper layer 9 may be provided, wherein the compound of the copper layer 9 with the surface side 6 "of the first ceramic layer 6 is preferably prepared by the" direct copper bonding "method or the AMB method. The connection of the copper layer 9 with the steel or stainless steel layer 8 takes place for example by means of hard or soft soldering or gluing. Furthermore, the second metal-ceramic substrate 3 assigned to the cold region 1b has at least one corrosion-resistant metal layer 10, preferably one

Stainless steel layer, aluminum layer or copper layer on, wherein the

Corrosion-resistant metal layer 10 is applied to the second structured metallization 5 opposite surface side 7 "of the second ceramic layer 7. When forming the corrosion-resistant metal layer 10 in the form of a

Copper layer, the compound may in turn be made in a "direct copper bonding" process or the AMB process or in the form of a stainless steel layer or aluminum layer by means of brazing, active soldering or gluing.

The metallic formed by the first and second metallization 4, 5

Contact surfaces 4 ', 5' are preferably rectangular in shape and each have two opposite longitudinal and broad sides a, b. These thus form so-called "pads" for the connection of electronic components, namely the thermoelectric generator components N, P. For this purpose, for example, a solder layer or solder is applied to the surface of the metallic contact surfaces 4 ', 5' opposite the ceramic layer 6, 7 and a solder joint with the respective one

Bonding region of the n- or p-doped semiconductor element N, P produced, wherein by the respective one of the metallic contact surfaces 4 ', 5', a metal bridge between the n- and p-doped semiconductor element N, P is produced and thus a Peltier

Element arises. This results in the illustrated in the figures and known meandering course of the n- or p-doped semiconductor element N, P and these interconnecting metallic contact surfaces 4 ', 5'. To form the metal bridges, the longitudinal sides a of a rectangular, metallic contact surface 4 ', 5' are approximately twice as long as the broad sides b of a rectangular, metallic contact surface 4 ', 5', i. the longitudinal and

Broad sides a, b preferably have a ratio of 2: 1. For example, the longitudinal side a between 0.5 mm and 10 mm and the broad side b between 0.1 mm and 2 mm. A thermoelectric generator module 1 has, for example, a module longitudinal axis LA and a module transverse axis QA running perpendicular thereto. In a

preferred embodiment are the rectangular, metallic

Contact surfaces 4 ', 5' in such a way on the first and second ceramic layer 6, 7th

arranged that the longitudinal sides a of the rectangular, metallic contact surfaces 4 ', 5' parallel to the module transverse axis QA and the broad sides b of the rectangular, metallic contact surfaces 4 ', 5' parallel to the module longitudinal axis LA. The first and second metal-ceramic substrate 2, 3 are in this case with their first and second structured metallization 4, 5 facing each other, that the rectangular, metallic contact surfaces 4 ', 5' are arranged in a gap to each other, in such a way that For example, by a rectangular, metallic contact surface 5 'of the second structured metallization 5, a metal bridge for an n- and p-doped semiconductor element N, P is formed, which are connected to two adjacent rectangular, metallic contact surfaces 4' of the first structured metallization 4. As a result, each of the columns S1 to Sy forms a series connection of a plurality of Peltier elements, wherein the series circuits of the Peltier elements in the columns S1 to Sy are preferably themselves connected in series with one another. 2 shows a schematic plan view of the contact surfaces 4 'of the first metal-ceramic substrate 2 is shown by way of example, wherein the rectangular,

metallic contact surfaces 4 'are preferably arranged like a matrix on the surface side 6' of the respective ceramic layer 6, in such a way that the

rectangular, metallic contact surfaces 4 'parallel to the module longitudinal axis LA extending rows R1, R2, Rx and parallel to the module transverse axis QA extending

Columns S1, S2, S3, Sy form. In the edge regions of the preferably rectangular first and / or second metal-ceramic substrate 2, 3, in which the connection of only one p- or n-doped semiconductor elements P, N is required, cuboidal metallic contact surfaces 5 'may also be used come. The contact surfaces 4 'assigned to a row R1, R2, Rx are provided at a distance from one another and in each case adjoin one another with one of their longitudinal sides a. The distance c between two adjacent contact surfaces 4 'of a row R1, R2, Rx is for example between 0.1 mm and 2 mm, preferably between 0.4 mm and 0.6 mm.

Analogously thereto, the contact surfaces 4 ', 5' assigned to a column S1, S2, S3, Sy are likewise arranged at a distance from one another on the respective ceramic layer 6, 7, for example at a distance d between 0.1 mm and 2 mm,

preferably between 0.4 mm and 0.6 mm, wherein two adjacent contact surfaces 4 ', 5' of a column S1, S2, S3, Sy each connect to one of their broad sides b to each other.

Between the spaced apart on the respective ceramic layer 6, 7 arranged rectangular metallic contact surfaces 4 ', 5' are

According to the invention separation or break lines 11, 11 'in the ceramic layer 6, 7 introduced, which preferably extend in the direction of the module transverse axis QA and / or in the direction of the module longitudinal axis LA. Thus, each rectangular, metallic contact surface 4 ', 5' is assigned by a separation or predetermined breaking lines 11, 11 'divided surface portion of the respective ceramic layer 6, 7, so that in case of breakage of the ceramic layer 6, 7 along one or more separation or Fracture lines 11, 11 'damage to the thermoelectric generator module 1 can be avoided. The separating or predetermined breaking lines 11, 11 'can be realized in the form of slots, notches and / or points and / or introduction of microcracks, which, starting from the surface 6', 7 'receiving the metallization 4', 5 ', at least over one tenth of the layer thickness of the respective ceramic layer 6, 7 extend. The recesses in the form of slots, notches and / or points preferably have a depth of one quarter to three quarters of the layer thickness the respective ceramic layer 6, 7, which may be between 0.1 mm and 1 mm.

The separation or predetermined breaking lines 11, 11 'are introduced after application of the structured metallizations 4, 5 in the ceramic layer 6, 7, preferably after completion of all soldering and bonding processes, for example by a laser treatment or a mechanical machining process, such as sawing. Preferably, laser-induced cutting processes or a thermal shock treatment find application of microcracks.

The ceramic layers 6, 7 consist for example of aluminum oxide (Al 2 O 3) and / or aluminum nitride (AIN) and / or of silicon nitride (Si 3 N 4) and / or of aluminum oxide with zirconium oxide (Al 2 O 3 + ZrO 2). The first and second structured metallizations 4, 5 are preferably in the form of metal layers or metal foils, preferably of copper or a copper alloy. If the ceramic layers consist of one of the abovementioned ceramics (Al.sub.2O.sub.3, AlN, Si.sub.3N.sub.4, Al.sub.2O.sub.3 + ZrO.sub.2), then the metal layers or metal foils forming the structured metallizations 4, 5 are joined using the DCB method, in particular for metallizations 4, 5 made of copper or copper alloys.

In addition, in an alternative embodiment, not shown, the metallizations 4, 5 may be at least partially provided with a metallic, preferably corrosion-resistant surface layer, for example a surface layer of nickel, silver or nickel and silver alloys. Such a metallic

Surface layer is preferably applied after the application of the metallizations 4, 5 on the ceramic layer 6, 7 and their structuring on the resulting rectangular, metallic contact surfaces 4 ', 5'. The application of the surface layer takes place in a suitable method, for example galvanically and / or by chemical deposition and / or by spraying or cold gas spraying. In particular, when using nickel, the metallic surface layer has, for example, a layer thickness in the range between 0.002 mm and 0.015 mm. at a surface layer of silver, this is applied with a layer thickness in the range between 0.00015 mm and 0.05 mm, preferably with a layer thickness in the range between 0.01 μηη and 3 μηη. By such a preference

Corrosion-resistant surface coating of the rectangular, metallic contact surfaces 4 ', 5', the local application of the solder layer or the solder and the connection of the solder is improved with the bonding region of the thermoelectric generator components GB.

FIG. 5 shows an embodiment variant of a thermoelectric generator module 1 according to the invention in which two metal-ceramic sub-frame arrangements according to FIG. 1 are connected to one another via a common steel or stainless-steel layer 8 and / or a common corrosion-resistant metal layer 10. Analogously, more than two such metal-ceramic substrate arrangements over a common steel or stainless steel layer 8 and / or a common

corrosion-resistant metal layer 10 in conjunction. In an advantageous

Embodiment variant can be a corrugation, i. E., Between at least two successive metal-ceramic-subrate arrangements forming in each case a thermoelectric generator module 1 in the common steel or stainless steel layer 8 and / or in the common corrosion-resistant metal layer 10 for compensation of thermal stresses. a manually or mechanically produced groove-shaped depression be introduced (not shown in Figure 5).

FIGS. 6 and 7 show two further variants of the thermoelectric generator module 1 according to the invention, which comprise at least one

Composite substrate, which essentially comprise a stack of two metal-ceramic-substrate arrangements according to FIG. In the embodiment according to FIG. 6, the metal-ceramic substrate arrangements formed according to FIG. 1 are arranged over a common metal layer 12, preferably one

Copper layer interconnected. FIG. 7 shows an embodiment variant in which the first and second metallizations 6, 7 of the two metal-ceramic sub-frame arrangements are on a common ceramic layer 13. FIGS. 8 to 12 show different embodiments of the steel or stainless steel layer 8 and / or the corrosion-resistant metal layer 10 of a thermoelectric generator module 1 according to the invention.

In Figure 8 is an example of a schematic sectional view through a

thermoelectric generator module 1 shown analogous to Figure 3. Different from this, however, are the steel or stainless steel layer 8 and / or the

corrosion-resistant metal layer 10 formed in several parts, wherein the resulting at least two steel or stainless steel layers 8 and / or

corrosion-resistant metal layers 10 are arranged spaced from each other and thereby the surface sides 6 ", 7" of the first and second ceramic layer 6, 7 are at least partially freely accessible. This results in at least one externally freely accessible surface portion 6 "', 7"' of the first and second

Ceramic layer 6, 7. This allows improved heat absorption in

Hot area 1 a or improved cooling in the cold area 1 b. Preferably, the at least two steel or stainless steel layers 8 and / or corrosion-resistant metal layers 10 with at least one edge region over the edge of the first and second ceramic layer 6, 7 protrude outwards and thus form fastening sections.

FIGS. 9 and 10 show a further alternative embodiment of the steel or stainless steel layer 8 and / or the corrosion-resistant metal layer 10, for producing a plurality of freely accessible surface sections 6 '', 7 '' the steel or stainless steel layer 8 and / or corrosion-resistant metal layer 10 are formed like a lattice. FIG. 10 shows a schematic side view of a lattice-type steel or stainless-steel layer 8, in which example several different lattice structures are provided. The lattice structure can be formed, for example, by a circumferential, preferably rectangular frame section 8 'and a plurality of approximately mutually parallel connecting web sections 8 ", which bulges of different shape and / or size can have. The bulges may be circular, triangular, rectangular, square or rhombic, for example. Such a grid-like steel or stainless steel layer 8 or corrosion-resistant metal layer 10 is preferably produced by stamping and then with the

Surface side 6 ", 7" connected by gluing or soldering, taking on the

Surface side 6 ", 7" of the first and second ceramic layer 6, 7 is preferably applied to a grating image-forming adhesive or a lattice-patterning solder is applied. The described lattice structure results in a plurality of window-like freely accessible surface sections 6 "', 7"'.

To increase the effective surface area of the steel or stainless steel layer 8 and / or the corrosion-resistant metal layer 10, the steel or stainless steel layer 8 and / or the corrosion-resistant metal layer 10 is profiled in the embodiment according to FIG. In the steel or stainless steel layer 8 and the corrosion-resistant metal layer 10, for example, recesses 14, 15 are introduced such that a plurality of rib-like surface sections arise.

FIG. 12 shows a variant embodiment of the thermoelectric generator module 1 in which the steel or stainless steel layer 8 and the corrosion-resistant metal layer 10 protrude outward over the edge regions of the first and second ceramic layers 6, 7 and respectively have a peripheral bead 16, 16 'there which are preferably directed towards each other. The free outer edges following the peripheral beads 16, 16 'of the steel or stainless steel layer 8 and the

Corrosion-resistant metal layer 10 in turn form mounting areas.

The steel or stainless steel layer 8 is in a preferred embodiment in an alloyed steel with a content of molybdenum and / or nickel / cobalt

produced. As a result, an adaptation of the thermal expansion coefficient of the ceramic layer 6 is possible. In particular, alloyed steel may be used in the following composition:

• 50% - 60% iron

• 27% - 31% nickel

• 1 5% - 1 9% cobalt

For example, alloyed steel consisting of 54% iron, 29% nickel and 1 7% cobalt is particularly suitable.

The invention has been described above by means of exemplary embodiments. It is understood that numerous changes and modifications are possible me, without this being the invention of the underlying idea of the invention.

LIST OF REFERENCE NUMBERS

1 thermoelectric generator module

1a hot area

1b cold area

2 first metal-ceramic substrate

3 second metal-ceramic substrate

4 first structured metallization

4 'contact surfaces

5 second structured metallization

5 'contact surfaces

6 first ceramic layer

6 ', 6 "surface sides

6 "'freely accessible surface section

7 second ceramic layer

7 ', 7 "surface sides

7 "'freely accessible surface section

8 steel or stainless steel layer

8 'frame section

8 "Verbal insurrection

9 copper layer

10 corrosion-resistant metal layer

10 'frame section

10 "Verbal steg ng esp

11, 11 'separating or predetermined breaking lines

12 common metal layer

13 common ceramic layer

14 recess

15 recess

16, 16 'circumferential bead a long sides

b broadsides

c distance

d distance

N, P thermoelectric generator component or n- / p-doped semiconductor element

LA module longitudinal axis

QA module transverse axis

R1, R2, Rx series

S1, S2, S3, SyC columns

Claims

claims

Thermoelectric generator module having a hot and cold region (1 a, 1 b) comprising at least a first, the hot region associated Metal l ceramic substrate (2) having a first ceramic layer (6) and at least one on the first ceramic layer (6) applied , structured first metalization (4) and at least one second metal-ceramic substrate (4) associated with the cold region (1b) having a second ceramic layer (7) and at least one structured second metal layer applied to the second ceramic layer (5) and a plurality of between the first and second structured metal metallization (4, 5) of the metal l ceramic substrates (2, 3) recorded thermoelectric generator components (N, P), characterized in that the first, the

Hot region (1 a) associated with metal-ceramic substrate (2) has at least one steel or stainless steel layer (8), wherein the first ceramic layer (6) between the first (4) and the at least one steel or stainless steel layer (8 ) is arranged.

Module according to claim 1, characterized in that between the first ceramic layer (6) and the at least one steel or stainless steel layer (8) at least one copper layer (9) is provided.

Module according to Claim 1 or 2, characterized in that the second metal-ceramic substrate (3) assigned to the cold region (1 b) has at least one corrosion-resistant metal layer (1 0), the second one

Ceramic layer (7) between the second structured metal lation (5) and the corrosion-resistant metal lschicht (1 0) is arranged.

Module according to claim 3, characterized in that the corrosion-resistant metal lschicht (1 0) is formed by a stainless steel, aluminum or copper layer. Module according to one of claims 1 to 4, characterized in that the first and second metal isation are structured such that they form a plurality of metallic contact surfaces (4 ', 5'), which are preferably rectangular and / or cuboidal.

Module according to claim 5, characterized in that the longitudinal sides (a) of a rectangular metal contact surface (4 ', 5') are approximately twice as long as their broad sides (b).

Module according to claim 5 or 6, characterized in that the longitudinal sides (a) of the rectangular metal contact surfaces (4 ', 5') run parallel to the module transverse axis (QA) and the broad sides (b) of the rectangular, metal l Isik contact surfaces (4 ', 5') paral lel to the module longitudinal axis (LA).

Module according to one of claims 5 to 7, characterized in that the longitudinal sides (a) between 0.5 mm and 1 0 mm and the broad sides (b) amount to between 0.2 mm and 5 mm.

Module according to one of claims 5 to 8, characterized in that the metallic contact surfaces (4 ', 5') are arranged in the manner of a matrix on the surface side of the respective ceramic layer (6, 7).

Module according to claim 9, characterized in that the rectangular metal contact surfaces (4 ', 5') are parallel to the longitudinal axis of the module (LA), extending rows (R1, R2, Rx) and parallel to the module transverse axis (QA) extending columns (S1, S2, S3, Sy) form.

Module according to one of claims 5 to 1 0, characterized in that two adjacent rectangular metal contact surfaces (4 ', 5') in the direction of the module transverse axis (QA) have a distance (d) of 0, 1 mm to 2 mm , Module according to one of claims 5 to 1 1, characterized in that two adjacent rectangular, metallic contact surfaces (4 ', 5') in the direction of the module longitudinal axis (LA) have a distance (c) of 0.1 mm to 2 mm.

Module according to one of claims 5 to 12, characterized in that between the spaced apart on the respective ceramic layer (6, 7) arranged rectangular, metallic contact surfaces (4 ', 5') separating or predetermined breaking lines (1 1, 1 1 ') are introduced into the ceramic layer (6, 7), which preferably extend in the direction of the module transverse axis (QA) and / or in the direction of the module longitudinal axis (LA).

14. Module according to claim 1 3, characterized in that the separation or predetermined breaking lines (1 1, 1 1 ') in the form of slots, notches and / or points and / or introduction of microcracks are realized.

Module according to claim 14, characterized in that the slots, notches and / or points of a separating or Sollbruchl inie (1 1, 1 1 ') starting from the metallization (4, 5) receiving surface side (6', 7 ' ) of a ceramic layer (6, 7) extend at least over a tenth of the layer thickness of the respective ceramic layer (6, 7).

Module according to claim 14 or 1 5, characterized in that the slots, notches and / or points of a separation or predetermined breaking line (1 1, 1 1 ') by a laser treatment or mechanical processing of the ceramic layer (6, 7) are produced ,

Module according to one of claims 1 to 1 6, characterized in that the ceramic layer (6, 7) is made of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide, and preferably a

Layer thickness in the range between 0.1 mm and 1, 0 mm. Module according to one of claims 1 to 1 7, characterized in that the first and second structured metallization (4, 5) in the form of metal layers or metal foils, preferably formed of copper or a copper alloy, which preferably has a layer thickness in the range between 0.03 mm and 1.5 mm.

Module according to one of claims 1 to 18, characterized in that the metallizations (4, 5) at least partially with a metallic

Surface layer are provided, for example one

Surface layer of nickel, silver or a nickel or silver alloy.

Module according to one of the preceding claims, characterized in that the thermoelectric generator components (N, P) are formed in the form of Peltier elements made of a differently doped semiconductor material, wherein the thickness of the semiconductor material is preferably between 0.5 mm and 8 mm.

Module according to one of the preceding claims, characterized in that the steel or stainless steel layer (8) and / or the corrosion-resistant metal layer (10) is formed in several parts, wherein at least two parts of the steel or stainless steel layer (8) and / or the corrosion-resistant metal layer (10) are arranged spaced apart from one another in such a way that at least one surface portion (6 "', 7"') of the ceramic layer (6, 7) which is freely accessible from outside arises.

Module according to one of the preceding claims, characterized in that the steel or stainless steel layer (8) and / or the corrosion-resistant metal layer (10) is formed structured or profiled. Module according to one of the preceding claims, characterized in that the steel or Edelstah lschicht (8) and / or d he corrosion-resistant metal lschicht (1 0) in an over the edge region of the ceramic layer (6, 7) projecting outwardly an encircling Have bead (1 6, 1 6 ').

Metal I ceramic substrate for use in a thermoelectric

Generator module (1) according to one of the preceding claims comprising at least one ceramic layer (6) and at least one on the ceramic layer (6) applied, structured metal lation (4), characterized in that the metal l ceramic substrate (2) at least a steel or stainless steel layer (8), wherein the ceramic layer (6) between the structured

Metal lization (4) and the at least one steel or stainless steel layer (8) is arranged.

Metal l ceramic substrate according to claim 24, characterized in that between the ceramic layer (6) and the at least one steel or

Stainless steel layer (8) at least one copper layer (9) is provided.

Metal I ceramic substrate according to claim 24 or 25, characterized in that the metal isation (4) is structured such that it forms a plurality of metal contact surfaces (4 '), which are preferably rectangular in shape and are arranged in spaced relation to one another ,

Metal l ceramic substrate according to claim 26, characterized in that the longitudinal sides (a) of a rectangular metal contact surface (4 ', 5') are approximately twice as long as their broad sides (b), wherein the

Longitudinal sides (a) preferably between 0.5 mm and 10 mm and the broad sides (b) between 0,

2 mm and 5 mm. 28. Metal l ceramic substrate according to claim 26 or 27, characterized in that the metallic contact surfaces (4 ') in a matrix-like manner on the surface side of Ceramic layer (6) are arranged, in rows (R1, R2, Rx) and columns (S1, S2, S3, S4, Sy).

29. Metal-ceramic substrate according to one of claims 26 to 28, characterized

characterized in that between the metallic contact surfaces (4 ') separating or

Predetermined breaking lines (11, 11 ') are introduced into the ceramic layer (6), which are preferably realized in the form of slots, notches and / or points and / or introduction of microcracks.

Metal-ceramic substrate according to claim 29, characterized in that the slots, notches and / or points of a separation or predetermined breaking line (11, 11 ') starting from the metallization (4) receiving surface side (6') of a ceramic layer ( 6) extend at least over one-tenth of the layer thickness of the ceramic layer (6).

Metal-ceramic substrate according to one of Claims 24 to 30, characterized in that the ceramic layer (6) is made of aluminum oxide,

Aluminum nitride, silicon nitride or aluminum oxide is prepared with zirconium oxide and preferably has a layer thickness in the range between 0.1 mm and 1.0 mm.

Metal-ceramic substrate according to one of claims 24 to 31, characterized in that the structured metallization (4) in the form of a

Metal layer or metal foil, preferably of copper or

Copper alloy is formed, which preferably has a layer thickness

Range between 0.03 mm and 1.5 mm.

33. Metal-ceramic substrate according to one of claims 24 to 32, characterized

in that the metallization (4) is at least partially provided with a metallic surface layer, for example one Surface layer of nickel, silver or a nickel or silver alloys.

4. A method for producing a metal-ceramic substrate (2), in particular in the form of a printed circuit board for a thermoelectric generator module (1) comprising at least one ceramic layer (6) and at least one on the ceramic layer (6) applied, structured metallization (4 ), characterized in that on the ceramic layer (6, 7) gegenüberl rising surface (6 ') directly or indirectly at least one steel or stainless steel layer (8) is applied.

5. The method according to claim 34, characterized in that the metallization (4) is structured such that a plurality of metallic contact surfaces (4 ', 5') form, which are preferably arranged like a matrix on the ceramic layer (6).

6. The method according to claim 34 and 35, characterized in that between the rectangular contact surfaces (4 ', 5') separating or predetermined breaking lines (1 1,

1 1 ') are introduced into the ceramic layer (6, 7) by means of laser treatment or sawing, preferably in the form of slots, notches and / or points and / or introduction of microcracks.

7. The method according to any one of claims 34 to 36, characterized in that the ceramic layer (6) made of aluminum oxide, aluminum nitride, silicon nitride or aluminum oxide with zirconium oxide and by a copper layer or

Copper alloy existing metallization (4) by DCB bonding or

Active soldering can be connected.

8. The method according to any one of claims 34 to 37, characterized in that the steel or stainless steel layer (8) directly to the ceramic layer (6, 7) is connected by brazing, active soldering or gluing.