Method for producing thermoelectric device equipped with heat sink

Abstract

The invention relates to a method for manufacturing a thermoelectric device equipped with a heat sink, comprising the following steps: A) producing (100) a first part of the thermoelectric device equipped with a heat sink, during step A) depositing a first series of cylinders made of a semiconductor material having a given type of doping by additive manufacturing; b) producing (200) a second part of the thermoelectric device, during step B), depositing, by additive manufacturing, a second series of pillars made of a semiconductor material having a doping of another type; c) assembling (300) a second part of the device to the first part.

Description

Technical Field

[0001] The invention relates to the field of manufacturing thermoelectric devices equipped with a heat sink. Background Art

[0002] Figure 1 The thermoelectric device is shown without a heat sink. Figure 2 Shows Figure 1 An enlarged, partially exploded view of a thermoelectric device is shown. Figure 3 A heat sink configured to be mounted against one face of a thermoelectric device is shown.

[0003] The thermoelectric device 10 generally comprises two substrates 11 and 12 made of non-conductive materials (usually ceramics), and metal connectors C11 and C12 are mounted on the two substrates 11 and 12, and pillars P made of p-type semiconductor materials and n-type semiconductor materials, respectively. p , P n Extending from the metal connectors C11 and C12. p , P n However, from a thermal point of view, such thermoelectric devices 10 operate in parallel.

[0004] The electrical performance of the thermoelectric device in generator mode is given by:

[0005] -Internal resistance R int =N×ρ np ×L / A+R met +R c , where: N is the number of np junctions, L is the length of the cylinder, A is the cross-sectional area of ​​the cylinder, and ρ np is the resistivity of the np junction. These various parameters make it possible to define the total resistance of the column, R met is the total resistance of the metal connection, and R c is the total resistance of the contact;

[0006] - Voltage V generated by the thermoelectric device (generator mode) under the influence of the temperature difference ΔT at the ends of the thermoelectric device: V = N × S np ×ΔT, where S np =S p -S n , S p and S n are the Seebeck coefficients of the p-pillar material and the n-pillar material, respectively.

[0007] Then, by definition, the useful electrical power P u It is represented as: P u =V 2 / 4R int .

[0008] In order to have high powers and therefore in particular high voltages and therefore high ΔT, it is of interest to have, for example, a heat sink 20 mounted against the substrate 12 .

[0009] Typically, the thermoelectric device 10 and the heat sink 20 are manufactured separately and then final assembly is performed therebetween.

[0010] As far as the thermoelectric device in question is concerned, it is necessary to provide a substrate made of electrically insulating material and to deposit the various metal connections. This is done for each substrate 11, 12. The columns of semiconductor material are usually produced by sintering. To this end, a plate of semiconductor material from which the semiconductor columns are to be made is sintered, and then the block is cut to the desired size. It will be understood that, on the one hand, this operation will be performed for p-doped columns; on the other hand, this operation will be performed for n-doped columns. Once these columns are obtained, it is necessary to place them in the correct position on the metal connections C11, C12, and it is necessary to ensure their mechanical strength on these columns, for example by brazing.

[0011] The heat sink 20 is composed of a base BSE, and a heat dissipation structure SDT extends from the base BSE. The heat sink 20 is usually made of a material with good thermal conductivity. The heat sink 20 can be manufactured in various ways, such as by processing a solid block of the material making up the heat sink 20 to obtain fins ( Figure 3 ) or other forms of heat dissipation structures SDT.

[0012] The thermoelectric device 10 itself and the heat sink 20 may be assembled using a paste (thermal conductive paste) that can be hardened under the action of heat, and / or assembled by mechanical assembly. Figure 4 It is shown how to assemble the thermoelectric device 10 and the heat sink 20 using the thermal conductive paste PT, for example.

[0013] There are many different steps in the manufacturing method. This has an impact on production time and manufacturing costs. In addition, the technology used to manufacture semiconductor pillars is only able to produce parallelepiped shapes in practice. This limits the range of sizes of thermoelectric devices, especially with respect to the intended application and the technical constraints imposed by the application.

[0014] An object of the present invention is to propose a method for producing a thermoelectric device equipped with a heat sink, which thermoelectric device does not have at least one of the above-mentioned disadvantages. Summary of the invention

[0015] In order to solve the above object, the present invention provides a method for manufacturing a thermoelectric device equipped with a heat sink, the method comprising the following steps:

[0016] A) Making a first part of a thermoelectric device, the first part being provided with a heat sink, according to the following sub-steps:

[0017] - providing a heat sink provided with a base which is flat and made of an electrically insulating material,

[0018] - depositing a first series of metal connectors on the base of the heat sink in a predetermined pattern, and

[0019] - depositing, by additive manufacturing, a first series of pillars made of semiconductor material with a given type of doping, such that the semiconductor pillars are deposited on one and only one of the two ends of each of the first series of metal connectors,

[0020] B) producing a second part of the thermoelectric device in the following sub-steps:

[0021] - providing a plate made of an electrically insulating material,

[0022] - depositing a second series of metal connectors on the plate in the same pattern as the first series of metal connectors, and

[0023] - depositing, by additive manufacturing, a second series of pillars made of a semiconductor material having another type of doping, such that the semiconductor pillars are deposited on one and only one of the two ends of a metal connector of the second series of metal connectors,

[0024] C) assembling the second part of the device to the first part of the device in the following sub-steps:

[0025] - arranging the free ends of the semiconductor pillars of the first part of the device against the free ends of each metal connection of the second part of the device, and at the same time arranging the free ends of the semiconductor pillars of the second part of the device against the free ends of each metal connection of the first part of the device, and

[0026] - Perform heat pressing.

[0027] The method according to the invention may comprise at least one of the following additional steps, taken alone or in combination:

[0028] The heat sink provided in step A) is entirely made of an electrically insulating material, such as ceramic;

[0029] - the plate provided in step B) is made of the same material as the heat sink provided in step A);

[0030] The heat sink provided in step A) comprises a heat dissipation structure extending from a base of the heat sink, the heat dissipation structure being made of a material selected from steel, aluminum (Al), titanium (Ti), copper zirconium alloy (CuZr) or graphite, the steel being, for example, 316L steel;

[0031] - The base of the heat sink is made of a material selected from mica, polymer or ceramic, such as

[0032] - the plate provided in step B) is configured to form a further heat sink, for example by the presence of channels in the plate;

[0033] - the heat sink provided in step A) is selected from a fin heat sink, a cylindrical heat sink or a channel heat sink, the cylindrical heat sink being formed, for example, by a solid cylinder;

[0034] - during step A), at least one series of additional pillars made of semiconductor material having the same type of doping as the semiconductor pillars of the first series of pillars is deposited, such that an additional semiconductor pillar is deposited at the end of each metal connection of the first series, parallel to the semiconductor pillars already present in the first series of pillars; and during step B), at least one other series of additional pillars made of semiconductor material having the same type of doping as the pillars of the second series of pillars is deposited, such that an additional semiconductor pillar is deposited at the end of each metal connection of the second series, parallel to the semiconductor pillars already present in the second series of pillars;

[0035] - the material forming the semiconductor pillar is selected from silicon (Si), silicon germanium (SiGe), bismuth telluride (Bi2Te3), or selected from the skutterudite family;

[0036] - The additive manufacturing technique is selected from: laser melting on a powder bed, such as selective laser melting or selective laser sintering; or direct energy deposition. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Further objects and features of the present invention will become more apparent from the following description made with reference to the accompanying drawings, in which:

[0038] Figure 1 A thermoelectric device without a heat sink is shown;

[0039] Figure 2 Shows Figure 1 An enlarged, partially exploded view of the thermoelectric device shown;

[0040] Figure 3 A heat sink configured to be mounted against one face of a thermoelectric device is shown;

[0041] Figure 4 shows how to assemble a thermoelectric device and a heat sink using thermal paste;

[0042] Figure 5 Schematically represents the main manufacturing steps of the method according to the present invention;

[0043] Figure 6a , Figure 6b and Figure 6c In the context of an example according to an embodiment of the present invention, Figure 5 The various sub-steps of the first main step of the manufacturing method shown;

[0044] Figure 7a , Figure 7b and Figure 7c In the context of the same example of an embodiment, Figure 5 The various sub-steps of the second main step of the manufacturing method shown;

[0045] Figure 8 Shown in the same example of the embodiment, in the embodiment Figure 5 Thermoelectric device obtained after the third and last main step of the manufacturing method shown;

[0046] Fig. 9 shows semiconductor pillars of different shapes obtainable using the additive manufacturing techniques employed in the context of the present invention;

[0047] Fig.10 represents another type of thermoelectric device obtainable using the manufacturing method according to the present invention;

[0048] Fig.11 represents another type of thermoelectric device obtainable using the manufacturing method according to the present invention;

[0049] Fig.12 Indicates a type of heat sink that can be used;

[0050] Fig.13 is another type of heat sink that can be used. DETAILED DESCRIPTION

[0051] like Figure 5 As schematically shown in FIG. , the present invention relates to a method for manufacturing a thermoelectric device DTE equipped with a heat sink DT, the method comprising the following steps:

[0052] A) manufacturing 100 a first part PP of a thermoelectric device DTE, the first part being equipped with a heat sink;

[0053] B) making 200 second parts DP of thermoelectric devices DTE; and

[0054] C) Assembling 300 the second part DP of the device DTE to the first part PP of the device DTE.

[0055] A more practical example is used to illustrate the manufacture of a thermoelectric device DTE through each of the main manufacturing steps A), B) and C).

[0056] Step A) is performed in the following sub-steps.

[0057] Firstly, a heat sink DT is provided which is equipped with a base BSE which is flat and made of an electrically insulating material.

[0058] turn out Figure 6a The portion shown.

[0059] Then, a first series of metal electrical connections PSCM1 is deposited on the base BSE of the heat sink DT in a predetermined pattern. This can be done by chemical vapor deposition (CVD) or physical vapor deposition (PVD), but is not limited thereto.

[0060] turn out Figure 6b The portion shown.

[0061] The base BSE of the heat sink DT serves as a substrate for depositing the metal connections. This simplifies production and saves time. It also makes it possible to reduce the thickness of the device at this point, thus reducing the overall thermal resistance.

[0062] Then, a first series of pillars PSPLT1 made of semiconductor material with a given type of doping (for example n-doping) is deposited so that the semiconductor pillars PLT1 are deposited on one and only one of the two ends of each metal connector CM1 in the first series of metal connectors PSCM1.

[0063] This produces Figure 6c The portion shown forms a first portion PP of the thermoelectric device DTE.

[0064] It should be noted that in the present invention, the semiconductor pillars are deposited by additive manufacturing.

[0065] There are several additive manufacturing techniques that may be suitable for the purposes of the present invention.

[0066] A technique called laser melting on a powder bed can be used. In this case, the powder is deposited in the form of a powder bed and then densified using a laser beam. This can be selective laser melting (SLM) or selective laser sintering (SLS).

[0067] Alternatively, direct energy deposition (DED) techniques can be used. In this case, the powder is deposited and densified directly by a laser or electron beam.

[0068] Step B) is performed in the following sub-steps.

[0069] Provide a plate PLQ made of an electrically insulating material, which Figure 7a Shown in.

[0070] Then, a second series of metal connections DSCM2 is deposited on the plate PLQ. This is done in the same pattern as the first series of metal connections PSCM1.

[0071] turn out Figure 7b The portion shown.

[0072] Then, a second series of pillars DSPLT2 made of semiconductor material with another type of doping (for example p-type) is deposited so that the semiconductor pillars PLT2 are deposited on one and only one of the two ends of the metal connector CM2 in the second series of metal connectors DSCM2.

[0073] Here too, the deposit is deposited using an additive manufacturing technique (eg one of those listed above). Advantageously, the same additive manufacturing technique is chosen here as used in step A).

[0074] This produces Figure 7c The portion shown forms the second portion DP of the thermoelectric device DTE.

[0075] Finally, a step C) for assembling the second part DP to the first part PP of the thermoelectric device DTE is carried out according to the following sub-steps.

[0076] First, the free end of the semiconductor column PLT1 of the first part PP of the thermoelectric device DTE is arranged against the free end of each metal connector CM2 of the second part DP of the thermoelectric device DTE. At the same time, the free end of the semiconductor column PLT2 of the second part DP of the thermoelectric device DTE is arranged against the free end of each metal connector CM1 of the first part PP of the thermoelectric device DTE.

[0077] In practice, this means, for example, turning the second portion DP of the thermoelectric device DTE against the first portion PP of the device. Of course, as a variant, it is possible to turn the first portion PP of the thermoelectric device DTE against the second portion DP of the device - it is the same thing.

[0078] This is followed by a heat pressing step. This makes it possible to ensure that the two parts PP, DP remain together.

[0079] The thermoelectric device DTE equipped with a heat sink DT is finally obtained. Figure 8 Shown in.

[0080] The heat sink DT provided in step A) may be made entirely of an electrically insulating material which is advantageously also a good thermal conductor. This makes it possible to avoid the risk of short circuits between the metal connections CM1 while ensuring a suitable thermal behavior.

[0081] For example, a ceramic material may be selected for this purpose. In this case, it should be understood that there is no need to add thermal conductive paste or other materials as in the prior art to assemble the heat sink to the thermoelectric module. Therefore, the thermal contact is improved by reducing the contact resistance.

[0082] The plate PLQ provided in step B) may then be made of the same material as the heat sink DT provided in step A).

[0083] Alternatively, the heat sink DT provided in step A) comprises a heat dissipation structure SDT extending from a base BSE of the heat sink DT, the heat dissipation structure being made of a material selected from steel (e.g. 316L steel), aluminum (Al), titanium (Ti), copper zirconium alloy (CuZr) or graphite. In this case, the base BSE of the heat sink DT is in a material selected from mica, polymer or ceramic (e.g. The purpose is to ensure good heat dissipation while avoiding the risk of short circuits between the various metal connectors CM1.

[0084] It should be noted that the plate PLQ provided in step B) may contain an enhanced heat dissipation function. In this way, the plate PLQ may be configured to form another heat sink. This may be achieved, for example, by the presence of channels within the plate PLQ. This may be achieved, for example, in Fig.10 The variation shown is shown. Fig.12 An example of a heat sink in the form of a plate equipped with channels is shown. A fluid can then be circulated to increase the heat transfer. The channels can also be configured to increase the exchange surface and / or the heat exchange coefficient.

[0085] The heat sink DT provided in step A) can be designed in various ways. In practice, the heat sink may include a heat dissipation structure in the form of fins arranged in parallel, but may also include a heat dissipation structure in the form of columns arranged in parallel, such as Fig.13 The heat dissipation structure shown in the form of a solid cylinder may also include Fig.12 The heat dissipation structure with channels is shown.

[0086] Fig.11 Another thermoelectric device obtainable using the invention is shown, in which at least two semiconductor columns arranged in parallel are present at each metal connection.

[0087] This makes it possible to optimize the electrical output performance of the thermoelectric device DTE. In the prior art, all semiconductor columns are electrically connected in series. In the prior art, all semiconductor columns are electrically connected in series. This can lead to high output voltages (several volts), which are sometimes incompatible with the associated electronic equipment. The possibility of connecting certain semiconductor columns in parallel makes it possible to reduce this output voltage while maintaining the generated power.

[0088] To achieve this, during step A), at least one series of additional pillars SAPLT1' made of semiconductor material with the same type of doping as the semiconductor pillars PLT1 in the first series of pillars PSPLT1 is deposited, so that at the end of each metal connector CM1 in the first series of metal connectors PSCM1, the additional semiconductor pillars PLT1' are deposited in a manner parallel to the semiconductor pillars PLT1 already present in the first series of pillars PSPLT1. Similarly, during step B), at least one other series of additional pillars SAPLT2' made of semiconductor material with the same type of doping as the pillars PLT2 in the second series of pillars PSPLT2 is deposited, so that at the end of each metal connector CM2 in the second series of metal connectors DSCM2, additional semiconductor pillars PLT2' are added, parallel to the semiconductor pillars PLT2 already present in the second series of pillars DSPLT2.

[0089] Where appropriate, Fig.11 In the embodiment of the present invention, the plate PLQ is functionalized to include a heat dissipation function, in this case by means of channels. Whatever variant is chosen, the material forming the semiconductor pillars can be chosen from silicon (Si), silicon germanium (SiGe), bismuth telluride (Bi2Te3), or from the skutterudite family. These materials can take the form of powders that can be used for additive manufacturing.

[0090] Example of embodiment: Thermoelectric device equipped with a heat sink

[0091] The purpose is to produce Figure 8 Thermoelectric device shown.

[0092] For step A), a fin-type heat sink DT made entirely of ceramic is provided. The metal connector CM1 is made by physical vapor deposition (PVD) on the base BSE of the heat sink DT. Each cylindrical metal connector is composed as follows: Cu (thickness = 200nm) + Ni (thickness = 5μm) + Au (thickness = 10nm). The semiconductor column PLT1 is obtained by powder bed melting, the powder is silicon germanium (SiGe), in this example it is n-doped powder, the laser power is between 5W and 200W.

[0093] For step B), we start with a solid plate PLQ made of the same ceramic as the heat sink provided in step A). ​​The metal connections CM2 deposited on the plate PLQ are identical to those deposited on the base BSE of the heat sink DT (same dimensions, same material, same deposition technique, same pattern, etc.). The semiconductor pillars PLT2 are identical to the pillars obtained in step A), the only difference being that they are p-doped and obtained using the same method under the same conditions.

[0094] Finally, the assembly in step C) is subjected to hot pressing, which can be performed at a temperature between 100° C. and 1000° C. for a period between 1 minute and 10 hours.

[0095] End of example.

[0096] Thermoelectric devices manufactured in this way can be used in all applications where a thermal gradient is available (e.g. transportation, industry, etc.), in RTG (Radioisotope Thermoelectric Generator) applications for SiGe, in Peltier type applications, or for making thermal sensors.

Claims

1. A method for manufacturing a thermoelectric device (DTE) equipped with a heat sink (DT), comprising the following steps: A) manufacturing (100) a first part (PP) of the thermoelectric device (DTE), the first part (PP) being provided with a heat sink, according to the following sub-steps: - providing a heat sink (DT) equipped with a base (BSE), said base (BSE) being flat and made of an electrically insulating material, - depositing a first series of metal connections (PSCM1) in a predetermined pattern on said base (BSE) of said heat sink (DT), and - depositing, by additive manufacturing, a first series of pillars (PSPLT1) made of semiconductor material with a given type of doping, such that the semiconductor pillars (PLT1) are deposited on one and only one of the two ends of each metallic connection (CM1) of said first series of metallic connections (PSCM1), B) producing (200) the second part (DP) of the thermoelectric device (DTE) according to the following sub-steps: - providing a plate (PLQ) made of an electrically insulating material, - depositing on said plate (PLQ) a second series of metallic connections (DSCM2) in a pattern identical to that of said first series of metallic connections (PSCM1), and - depositing, by additive manufacturing, a second series of pillars (DSPLT2) made of a semiconductor material having another type of doping, such that the semiconductor pillars (PLT2) are deposited on one and only one of the two ends of a metal connection (CM2) of said second series of metal connections (DSCM2), C) assembling (300) said second part (DP) of said device to said first part (PP) of said device according to the following sub-steps: - arranging the free end of the semiconductor pillar (PLT1) of the first part (PP) of the device against the free end of each metal connection (CM1) of the second part (DP) of the device, and at the same time arranging the free end of the semiconductor pillar (PLT2) of the second part (DP) of the device against the free end of each metal connection (CM1) of the first part (PP) of the device, and - Perform heat pressing.

2. The method according to claim 1, wherein: The heat sink (DT) provided in step A) is entirely made of an electrically insulating material, such as ceramic.

3. The method according to the preceding claim, wherein: Said plate (PLQ) provided in step B) is made of the same material as said heat sink (DT) provided in step A).

4. The method according to claim 1, wherein: The heat sink (DT) provided in step A) includes a heat dissipation structure (SDT) extending from the base of the heat sink (DT), and the heat dissipation structure is made of a material selected from steel, aluminum (Al), titanium (Ti), copper zirconium alloy (CuZr) or graphite, and the steel is, for example, 316L steel.

5. The method according to the preceding claim, wherein: The base (BSE) of the heat sink (DT) is made of a material selected from mica, polymer or ceramic, such as 6. A method according to any one of the preceding claims, wherein: Said plate (PLQ) provided in step B) is configured to form a further heat sink, for example by the presence of channels within said plate.

7. A method according to any one of the preceding claims, wherein: The heat sink provided in step A) is selected from a fin-type heat sink, a column-type heat sink or a channel-type heat sink. The column-type heat sink is formed of, for example, a solid cylinder.

8. A method according to any one of the preceding claims, wherein: - during step A), at least one series of additional pillars (SAPLT1') made of semiconductor material having the same type of doping as said semiconductor pillars (PLT1) of said first series of pillars (PSPLT1) is deposited, so that at said end of each metal connection (CM1) of said first series of metal connections (PSCM1) an additional semiconductor pillar (PLT1') is deposited, said additional semiconductor pillar being parallel to said semiconductor pillars (PLT1) already present in said first series of pillars (PSPLT1); - During step B), at least one other series of additional columns (SAPLT2') made of semiconductor material having the same type of doping as the columns (PLT2) in the second series of columns (PSPLT2) is deposited, so that additional semiconductor columns (PLT2') are deposited at the ends of each metal connection (CM2) in the second series of metal connections (DSCM2), and the additional semiconductor columns are parallel to the semiconductor columns (PLT2) already existing in the second series of columns (DSPLT2).

9. A method according to any one of the preceding claims, wherein: The material forming the semiconductor pillars (PLT1, PLT1', PLT2, PLT2') is selected from silicon (Si), silicon germanium (SiGe), bismuth telluride (Bi2Te3), or selected from the skutterudite family.

10. A method according to any one of the preceding claims, wherein: The additive manufacturing technology is selected from: - Laser melting on a powder bed, such as Selective Laser Melting (SLM) or Selective Laser Sintering (SLS), or -Direct Energy Deposition (DED).

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