Thermal lens electrodes for improved performance in thermoelectric generators

Abstract

Exemplary thermoelectric devices and methods are disclosed herein. Thermoelectric generator performance is improved by forming an isothermal field within the body of thermoelectric particles, thereby increasing the power output of a thermoelectric generator module. In one embodiment, a thermoelectric device includes particles including semiconductor material, a first metal layer surrounding a first portion of the particles, and a second metal layer surrounding a second portion of the particles. The first metal layer and the second metal layer are arranged in close proximity to each other around the perimeter of the particles. The particles are exposed at the perimeter. And the perimeter is arranged at the sidewall height around the particles to provide a nonlinear effect on the power output of the thermoelectric device by improving the isothermal surface curvature within the particles. The device also includes a metal container bonded to the particles thermally and electrically.

Description

[0001] Related Applications

[0002] This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 62 / 768,679, filed on November 16, 2018, entitled “Thermal Focusing Advantages in Thermoelectric Devices for Improved Performance,” the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments herein generally relate to thermoelectric devices made from semiconductor components. More specifically, these embodiments relate to design improvements regarding the nature of direct contact between electrodes and semiconductor particles, resulting in increased power output of thermoelectric generators. Background Art

[0004] Thermoelectric modules have been the subject of alternative power generation research for decades and within the field of thermoelectric generators there are several products for obtaining electrical power from waste heat. Thermoelectric modules can be used for alternative power generation in Seebeck mode to convert heat flux into electrical flux. Conversely, in Peltier mode, electrical flux can be used to drive heat flux to provide refrigeration. Thermoelectric devices for power generation are one of the key drivers of research, as waste heat that would otherwise be wasted to the environment can be recycled as electrical energy and can be used in remote areas or fed back into the grid via an inverter.

[0005] However, this method of generating electricity has encountered obstacles in the basic parameter of cost per watt compared to other alternative power generation methods such as solar technology. The main reasons for this cost barrier are the inherent thermoelectric properties of the semiconductors in the device and the manufacturing costs of the heat exchanger system that provides the hot and cold surfaces required to convert thermal energy into electrical energy. Therefore, if thermoelectric energy production methods are to be widely adopted in clean energy conversion production and at a larger power scale, especially in the megawatt power range and above, it is crucial to make progress in all aspects of manufacturing thermoelectric generators (TEGs). Summary of the invention

[0006] The systems and methods proposed herein provide a cost-effective method for mass production of clean energy by using a larger semiconductor surface area and particle volume of thermoelectric particles. In one embodiment, a new type of electronic component is proposed that uses favorable consistency of electrical and thermal properties to improve the performance of thermoelectric generators. One method of building thermoelectric modules (e.g., operating in Seebeck and / or Peltier mode) is based on sequential layered assembly using automated technology, such as using pick and place equipment to automatically place components. Thermoelectric modules can be manufactured in this way for mass production.

[0007] In one embodiment, the TEG is configured as a semiconductor that includes a shape that is typically a cube or cylinder, but the shape can have any form that allows for a thermal focusing effect, such as a rectangular parallelepiped, a sphere, a truncated cone, or other such polyhedron, where thermal energy can be directed by using the corners and vertices of adjacent sides of the semiconductor particles. Each particle can be electrically and thermally bonded to an electrical interconnect using two metal electrodes and forming a series circuit to conduct current generated by the thermoelectric effect in the presence of a thermal gradient. Thus, an array of particles arranged in this manner can be packaged to form a module, typically a flat package.

[0008] Typically, two flat metal electrodes of the particle are placed on directly opposing parallel surfaces of the particle and conveniently attached to the interconnect by printing solder paste on the interconnect. The solder can then be reflowed to complete the bonding process between the components. More specifically, the present embodiment relates to design improvements regarding the geometric properties of the electrodes tightly bonded to the particle, which improves the overall performance of the thermoelectric device by focusing thermal energy within the body of the particle. Due to the nature of the isotherm profile within the particle, the power output of the TEG may be significantly increased.

[0009] The components used for the thermoelectric effect are particles of semiconductor materials, wherein the material has suitable thermoelectric properties that match its dopant. Two materials are usually required to make thermoelectric devices, one is a material with electrons as the main charge carriers (N-type), and the other is a material with holes as the main charge carriers (P-type). Typically, each particle has a cubic shape and has two opposing planar electrodes, a hot electrode and a cold electrode, on parallel planes on two surfaces of the particle for heat injection and current injection on the hot side in a standard circuit layout. The isotherms generated in the particle volume between the hot and cold electrodes of the particle are therefore planar and parallel to the electrodes. Therefore, the thermal gradient vector perpendicular to the isotherms within the particle is parallel to the sidewall plane of each particle from the top to the bottom of the particle, and the current vector generated by the thermoelectric effect is usually parallel to the thermal gradient vector in the body of each particle. This geometric arrangement fixes the area of ​​the isotherms to the area of ​​the particle electrode.

[0010] In general, planar electrical interconnects are placed on the bottom and top halves of the package to connect the current between the particles in the module in series, providing heat transfer and electrical continuity. The electrical interconnects are typically copper and also provide the output electrodes of the module. As a result, the layout of the thermoelectric module has a device geometry that facilitates surface mount technology methods.

[0011] Furthermore, the particles are typically cubic in shape, as it is a space filling shape, whereas cylindrical particles are not. A higher packing density of effective thermoelectric particles generally allows for a larger effective volume in the module to convert heat to electricity in a generator and / or provide effective cooling in Peltier mode. Herein, a cube will be referred to as a square particle where the two sides are equal in length and the height or thickness has different values.

[0012] Heat transfer into the particle is typically limited to the top and bottom surfaces of the cubic (or cylindrical) particle. This article analyzes the modification of heat transfer to the bulk of the semiconductor particle and provides a method to increase the effective heat transfer area of ​​the thermoelectric effect through heat transfer by using the particle sidewall as a path for heat transfer from a larger area of ​​the sidewall. Increasing the module output power of the electrode of this new component can be achieved by modifying the isotherms inside the particle body to increase the effective area of ​​the thermoelectric effect. The power output generated by the thermoelectric effect has both linear and nonlinear effects due to the increased effective area. In the case of a thermoelectric generator, the thermoelectric conversion of focused thermal energy into electrical energy generally results in more output power per particle volume.

[0013] In one embodiment, a thermoelectric device includes a particle including a semiconductor material, a first metal layer surrounding a first portion of the particle, and a second metal layer surrounding a second portion of the particle. The first metal layer and the second metal layer are arranged in proximity to each other around a perimeter of the particle. The particle is exposed at the perimeter. The perimeter is arranged at a sidewall height around the particle to provide a nonlinear effect on the power output of the thermoelectric device by modifying the isothermal surface curvature within the particle. The device also includes a metal container thermally and electrically bonded to the particle.

[0014] In another embodiment, the isotherm surface curvature within the particle can be used to increase the effective surface area for the thermoelectric effect within the volume of the particle via heat injection through the sidewall. In another embodiment, the first metal layer and the second metal layer include a higher thermal conductivity than the particle. For example, at least one of the first metal layer and the second metal layer includes copper. In another embodiment, at least the particle and the second metal layer are configured into a shape (e.g., a cube and / or a cylinder) that can be used to increase the thermal lens effect of the thermoelectric device.

[0015] In one embodiment, the first metal layer and the second metal layer are electrically isolated from each other. In this regard, the first metal film and the particle may include a sloped edge proximate the perimeter of the particle to electrically isolate the first metal layer and the second metal layer from each other.

[0016] In one embodiment, a method of manufacturing a thermoelectric device includes: metalizing a plurality of semiconductor particles using one or more metal layers; and removing a portion of the metal layer around the perimeter of the semiconductor particles to form a gap with each of the semiconductor particles, the gap exposing the semiconductor particles. The method also includes: forming a plurality of cups from copper; electroplating the cups using nickel; and coating a portion of the cups using solder. The method also includes: placing one of the particles in each of the cups so that the sidewall height of each cup matches the gap position of each particle to provide a nonlinear effect on the power output of the thermoelectric device by modifying the isotherm surface curvature within the particles; curing the solder to adhere the particles to the cups; and mounting the cups to a substrate to form the thermoelectric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present disclosure will be readily understood by the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals denote like structural elements, and in which:

[0018] The use of cross-hatching or shading in the drawings is generally used to clarify boundaries between adjacent elements and also to aid in the legibility of the drawings. Thus, the presence or absence of cross-hatching or shading does not convey or indicate a preference or requirement for a particular material, material property, component proportions, component size, commonality of similar illustrated components, or any other feature, attribute, or characteristic of any element shown in the drawings.

[0019] Furthermore, it should be understood that the (relative or absolute) proportions and sizes of the various features and elements (and collections and groupings thereof) provided in the accompanying drawings, as well as the boundaries, separations, and positional relationships therebetween, are merely intended to facilitate understanding of the various embodiments described herein, and therefore, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for the illustrated embodiments to exclude the embodiments described with reference thereto.

[0020] Some embodiments will now be described, by way of example only, and with reference to the drawings. The same reference number represents the same element or the same type of element on all drawings.

[0021] Figure 1 An exemplary square semiconductor particle having four thermally conductive side walls (TEFP) is shown.

[0022] Figure 2An exemplary thermal lens electrode (TLE) component is shown.

[0023] Figure 3 An exemplary thermally enhanced thermoelectric component (TETC) component using square semiconductor particles having four thermally conductive sidewalls is shown.

[0024] Figure 4 An exemplary single thermocouple pair arrangement comprising two square semiconductor particles having four copper sidewalls is shown.

[0025] Figure 5 An exemplary single thermocouple pair arrangement is shown having four copper sidewalls.

[0026] Figure 6 An exemplary bottom component of a thermocouple arrangement is shown in transparent schematic form.

[0027] Figure 7 is an exemplary computational grid in a thermocouple pair circuit where the sidewall starts from the top of the particle.

[0028] Figure 8 The relationship between the device power of the thermocouple pair circuit and the particle thickness normalized to the power output of the particle device is shown.

[0029] Fig. 9 The normalized linear maximum power output is shown relative to a particle without metal sidewalls.

[0030] Fig.10 Shown is the normalized nonlinear maximum power output versus nickel metal sidewall coverage for a 1 mm thick particle relative to a particle without metal sidewalls.

[0031] Fig.11 An exemplary cross section of the thermal gradient through the center of a particle in the presence of sidewall metal is shown, causing a thermal lens with a sidewall thickness of a 0.05 mm hole centered at 0.5 mm of the particle height (e.g., the thermal lens exists symmetrically in the top and bottom halves of the particle).

[0032] Fig.12 An exemplary cross section of a 100°C thermal gradient through the center of a particle is shown without sidewall metal, resulting in a planar isotherm.

[0033] Fig.13 An exemplary thermal focusing is shown for the case of a 0.1 mm wide hole located at the top of a 1 mm sidewall thickness particle.

[0034] Fig.14 An exemplary thermal focusing is shown for the case of a 0.05 mm wide hole located at the bottom of a 0.2 mm nickel thickness particle.

[0035] Fig.15A Example resistive load losses for a thermocouple pair are shown as a function of the center of the metal hole.

[0036] Fig. 15B The device power output for the same thermocouple pair is shown.

[0037] Fig.16 An exemplary maximum device power output versus external resistive load factor is shown with nickel metal sidewall coverage as a parameter.

[0038] Fig.17 An exemplary parametric relationship between normalized maximum power output and metal sidewall coverage for a thermocouple pair with metal thickness as a parameter is shown.

[0039] Fig.18 Exemplary current-voltage load lines are shown for a three thermocouple pair arrangement with metal sidewall coverings on all four sidewalls.

[0040] Fig.19 Show Fig.18 An exemplary power-voltage relationship for a three-thermocouple pair arrangement.

[0041] Fig. 20 Exemplary current-voltage load lines at four temperatures (50° C., 100° C., 150° C., 200° C.) are shown for three 1 mm thick sidewall cases.

[0042] Fig.21 An exemplary thin metallization particle is shown ready for bonding to a TLE component.

[0043] Fig. 22 An exemplary subcomponent layer of a TETC is shown (eg, metallization particles, solder layer, and TLE that together comprise the TETC).

[0044] Fig.23 An exemplary approach showing component packaging geometry for TETC.

[0045] Fig.24 Another exemplary approach to component packaging geometry for TETC is shown.

[0046] Fig.25A and 25B An exemplary comparison of two visualizations of isotherms calculated using the Fourier method of separation of variables is shown. DETAILED DESCRIPTION

[0047] The accompanying drawings and the following description illustrate specific exemplary embodiments disclosed herein. It will therefore be appreciated that one skilled in the art will be able to design various arrangements that, although not explicitly described or illustrated herein, embody various principles and are included within the scope of the claims. Furthermore, any examples described herein are intended to aid in understanding the principles of the embodiments and are to be understood as not being limited to such specifically described examples and conditions. Therefore, the embodiments are not limited to the specific examples described below.

[0048] The exemplary thermoelectric devices and methods disclosed herein improve the performance of thermoelectric generators by forming an isothermal field within the body of thermoelectric particles, thereby increasing the power output of the thermoelectric generator module. In the following examples, it will be shown computationally that there is a significant advantage in power generation by the presence of a metal layer on the sidewalls of the particles, and the increase in power output generally depends on the thickness of the metal layer, the metal coverage on the sidewalls, and the number of sidewalls with metal coverage on the particles. The presence of thermally conductive metal on the sidewalls effectively increases the effective area of ​​the thermoelectric effect of the isotherm by inducing a three-dimensional curvature of the isotherm.

[0049] In one embodiment, a thermoelectric device includes a particle including a semiconductor material, a first metal film surrounding a first portion of the particle, and a second metal film surrounding a second portion of the particle. The first metal film and the second metal film are arranged in proximity to each other around the perimeter of the particle. The particle is exposed at the perimeter, and the perimeter is arranged at a sidewall height around the particle to provide a nonlinear effect on the power output of the thermoelectric device by modifying the isothermal surface curvature within the particle. The device also includes a metal container thermally and electrically bonded to the particle.

[0050] Geometric Effects in Thermoelectric Seebeck Effect

[0051] It has been shown analytically that the output power of the thermoelectric generator increases as the thickness of the thermoelectric particles decreases, up to the point where the thermal conductivity of the semiconductor particles cannot support the thermal gradient. Naturally, at this point, the output power decreases to zero as the particle thickness approaches zero. The same relationship has been shown computationally, and the results are verified in this paper as a confirmation of the computational model using ideal and basic thermocouples for the component model, without the inclusion of all bonding layers. More specifically, the maximum thermoelectric power can be generated for particle thicknesses between about 80-100 microns, depending on the physical properties of the semiconductor. The maximum current may occur at thickness values ​​slightly smaller than the maximum power, while the voltage increases monotonically with particle thickness. Therefore, the maximum power point is slightly larger than the particle thickness for maximum current.

[0052] The study of thermocouple pair devices is validated here by analytical methods and using computational models. Here, the temperature-dependent properties of the packaged components are used. Ideal conditions are used, such as no electrical contact resistance between the thin film metal electrode on the semiconductor and the semiconductor, and no contact heat transfer coefficient is used in the modeling. The model includes the temperature-dependent properties of the relevant packaging materials such as copper, aluminum, except for the solder layer between the TLE and the particles. The solder layer is not included because the layer is relatively thin and has a much higher thermal conductivity than the particles. In one embodiment, the modeling includes measured properties of the semiconductor. In one embodiment, measurements are performed on semiconductor rods of sintered semiconductors and data of the Seebeck coefficient, electrical conductivity and thermal conductivity as a function of temperature are collected.

[0053] The computational model used in this paper shows approximately the same maximum power point at about 100 microns, which is consistent with previous analytical and computational results. Figure 8 In thermoelectric theory, the power output of a particle is related to the thickness of the particle and the cross-sectional area of ​​the particle.

[0054] For the thickness range of maximum power for a given material, particles are considered thick films less than about 100 microns. For the case of hot or cold pressing and heat treatment, some semiconductor materials are brittle and tend to break after sintering, such as the bismuth and antimony telluride used here. Therefore, for thermoelectric thick films, the use of automated pick and place techniques may not be practical due to their fragility during handling. In general, thick films should be made by printing, dispensing or plating methods unless they are grown as single crystals and cut into small pieces in wafer form.

[0055] Based on the above results regarding optimal particle thickness, and the fact that such thermoelectric telluride-based particles are fragile, an alternative approach is suggested rather than making the particles thinner to obtain more electrical power per particle. This approach involves modifying the thermal gradient within thicker particles by using a metallic sidewall layer of the particles. Metals are typically extremely hot and electrically conductive compared to thermoelectric semiconductors. These physical properties are unique advantages for controlling the isothermal temperature field within the bulk of the semiconductor particle, which in turn increases the effective volume for the thermoelectric effect. It has been computationally shown that by injecting thermal and electrical energy through the sidewalls of the particles adjacent to the thick metal film, the thermoelectric power increases in both a linear and nonlinear manner.

[0056] Bonding metal to the sidewalls of thermoelectric particles with high thermal conductivity to improve the thermal gradient inside the particles is another alternative method to effectively increase the effective volume of the thermoelectric effect to obtain more electrical energy. The method involves improving the thermal gradient inside the particle by using a metal sidewall layer that provides thermal focusing. One reason for the increase in thermoelectric power generation within a given semiconductor volume is to control the thermal gradient. Specifically, controlling the shape of the thermal gradient is a reason for increasing the effective volume of the thermoelectric effect. By introducing three-dimensional curvature in the isotherms, it is computationally shown that by injecting heat and current through the sidewalls of particles coated with a thick metal layer, the thermoelectric power will increase as the effective thermoelectric volume of the particles increases. The thermal gradient curvature generated by the thermal lens effect (focusing) changes the shape of its isotherms within the internal volume of the particle.

[0057] A surface mount technology approach for assembling metallized thermoelectric semiconductor particles with other components in a thermoelectric module depends on the material, size and thickness of the particles and ease of handling. For example, automation in module assembly can produce a cost-effective method that can be automatically picked and placed for high-volume manufacturing. Metallized particles with edge sizes ranging from a few millimeters and thicknesses of approximately 0.5-1.5 mm are easily placed in trays where robots can easily build thermoelectric modules (or sleeves) consisting of hundreds of particles in a few minutes. Particles in this size range have a clear advantage in that they are easily handled and tracked by operators in certain process operations (for example, where the process is not fully automated).

[0058] Some metallization methods are also more cost-effective, especially if semi-automated within reasonable limits. Electroplating is one such method, where the thickness of the metal electrode layer can be easily controlled during electroplating or chemical plating.

[0059] Heat injection from the sidewall is achieved by a layer of a relatively high thermal conductivity material on the sidewall, such as a metal, into a material of low thermal conductivity, such as a thermoelectric semiconductor. The ratio of thermal conductivity is important in the heat injection of heat through the sidewall of the particle. Metals such as copper, nickel or silver can be electroplated to form such layers. The thicker the sidewall material, the higher the thermal conductivity can be produced, and more heat is transferred from the sidewall to the inside of the particle according to the conductivity. This heat injection can make the shape of the thermal gradient in the modified particle. Compared with the plane isotherms generated inside the particle when only using standard electrodes at the top and bottom of the particle, the spatial modification of the thermal gradient may cause the change in the spatial generation of the current provided by the thermoelectric effect.

[0060] The power generated by the thermoelectric effect can be directly dependent on the area of ​​the thermal gradient, and this area can be increased without changing the volume of the particle. The internal volume of the particle between the top and bottom electrode surfaces can also be used through the sidewalls of the particle. Once heat is injected through the electrodes on the sidewalls and the top and bottom electrodes, the isotherms within the particle defined by the thermal gradient are generally no longer parallel to the top and bottom surfaces (e.g., two-dimensional parallel isotherms) as in the absence of metal on the sidewalls.

[0061] Injecting heat into the sidewalls can change the shape of the isotherms to a curved surface (dome shape) within the particle, with a three-dimensional shape instead of a two-dimensional flat shape, thereby increasing the area of ​​the thermal gradient. This change in the shape of the 3D surface isotherms increases the effective area of ​​the thermoelectric effect within the particle volume, thereby increasing the thermoelectric power generated. Since there is also charge carrier injection through the sidewalls (e.g., due to the high conductivity of the metal), the thermoelectric current is also increased because it allows the enhanced thermal gradient to drive more charge carriers to the opposite electrode.

[0062] The thermoelectric current and thus the power generated by the thermoelectric effect is proportional to the effective surface area of ​​the thermal gradient formed by the parallel isotherms. This current is usually proportional to the second-order spatial derivative of the temperature gradient and is therefore usually parallel to the normal of the thermal gradient in the entire volume where the thermoelectric effect occurs. In steady state, the second-order spatial derivative of the temperature field is proportional to the Joule heating effect (~I 2 ) is proportional to the following equation:

[0063]

[0064] where I is the thermoelectric current and J neglects the contribution of the thermoelectric current when the Thomson contribution of the thermoelectric current is balanced to zero.

[0065] The second derivative of a variable describes its curvature, and the inverse of the curvature is the radius. Therefore, the thermal lens electrode effect reduces the radius of curvature of the isotherms within the particle volume and produces dome-shaped isotherms, thereby increasing the thermoelectric current and output power. By effectively increasing the surface area of ​​the isotherms without increasing the size or shape of the particles, more energy can be generated within the particle volume. Therefore, by guiding or focusing the heat transport per semiconductor volume, more thermal energy can be converted into electrical energy. When using thermally enhanced thermoelectric particles, the power output of thermoelectric modules can be increased by up to about 60%.

[0066] In summary, since the thermoelectric effect depends directly on the area of ​​the thermal gradient, modifying the thermal gradient within the particle through TLE can increase the output power. The power is usually increased by modifying the isotherms to give the particle a 3D curvature, increasing the effective area of ​​the thermoelectric effect inside the particle. Therefore, more isothermal area is generated per semiconductor volume. By increasing the surface area of ​​the isotherms, more current can be generated in the particle and therefore more power. Since the thermoelectric current is proportional to the effective surface area of ​​the isotherms within the particle, more electrical energy can be converted by enhancing heat transfer.

[0067] Computational analysis and related theory

[0068] The computational analysis was performed using the Comsol multiphysics program including the Multiphysics Thermoelectric Module. The modeling scale was chosen to facilitate meshing of small parts and high geometric aspect ratios. For these results, a particle size of 6x6x1 mm was chosen and all other parts were automatically geometrically scaled to match the size of the particles without changing the basic configuration of the thermocouple pairs. All calculations were based on steady-state conditions and were independent of time. That is, the boundary conditions at each interface were essentially constant in temperature and had no time dependence. Due to these fixed boundary conditions, the heat injection on each sidewall could be added in a linear manner.

[0069] In the computational analysis, some metal layers were omitted to make the meshing easier to align at the interfaces between parts and reduce the computational time. Alternatively, the part thickness was increased to accommodate the meshing, accompanied by appropriate reductions in physical properties to effectively maintain thermal and electrical conductivity. For example, Figure 1 A thin metal film that does not contain particles is required for soldering to the TLE 110 because both have relatively very high thermal and electrical conductivities compared to the particles. Figure 1 In FIG, a square semiconductor particle 100 is shown inserted into a TLE 110, the particle having four thermally conductive sidewalls 111 starting from the top electrode, with a 0.25 mm gap in the sidewall metallization at the bottom of the particle. The particle 100 and the TLE 110 can be bonded together with solder to provide a thermally enhanced thermoelectric component (TETC). In addition, convergence of the multi-physics solution is easier to achieve when components with high aspect ratio thickness are avoided. In most cases, the temperature difference from the hot side to the cold side is 100°C. Thermally induced stresses between components are neglected because the package through the mid-plane of the particle is symmetrical and is used to stress balance thermal stresses.

[0070] Figure 2 An exemplary TLE component 110 with a 1 mm wall 111 for a particle 100 is shown. The TLE component 110 is a subcomponent of the TETC used to attach the particle 100 using a solder layer within the TLE 100. This thickness was not exceeded for analysis. In one embodiment, Figure 2 The thermal lens electrodes shown are either copper or nickel, with different metal thicknesses and heights of this component used to determine the nature of the thermal lens effect.

[0071] exist Figure 3 , a square semiconductor particle 100 is shown within four thermally conductive sidewalls 111 of a TLE component 110. In one embodiment, the particle 110 starts with a top electrode, leaving a 0.25 mm metal gap 114 at the bottom of the particle. The semiconductor particle 100 is shown with a bevel geometry 112 to electrically isolate the top and bottom electrodes.

[0072] Figure 3 The components are exemplarily integrated into Comsol's geometry for a thermocouple pair with all ideal interfaces, i.e. no electrical or thermal barriers, as these vary widely in the industry depending on the materials used in the assembly of the thermoelectric device. Therefore, ideal devices are used to describe the results, with the expectation that lower performance can be expected under non-ideal conditions, and non-ideal results can be easily included by the methods explained above. Furthermore, the models use temperature-dependent materials that can be measured (semiconductors) and are also included in Comsol's material library.

[0073] Figure 4 An exemplary computational geometry of a single thermocouple pair device 120 is shown, which includes two semiconductor particles in a square shape, N-type and P-type particles with four copper sidewalls as thermocouple pairs. In this embodiment, a side view of the thermocouple pair device 120 is shown with two square semiconductor particles, each particle having four copper sidewalls, each copper sidewall starting at the bottom electrode interconnect on each particle. The sidewall thickness is 1 mm, and the metal gap at the top electrode interconnect is 0.15 mm.

[0074] The copper metal resistive load is shown above the particle, and the load line is generated by parameterizing the modified resistivity to simulate the varying load. Fig.18 and Fig. 20 The other parameters are the metal sidewall thickness and the temperature difference between the cold and hot sides. As expected, these are linear relationships.

[0075] Figure 5 is an isometric view of an exemplary single thermocouple pair device 120 having four copper sidewalls 0.65 mm in height and 0.2 mm thick from the top electrode of each particle, and a metal gap of 0.35 mm at the bottom electrode.

[0076] Figure 6 Another view of a thermocouple pair arrangement 120 with two particles 100 is shown. Figure 6Schematically shown from bottom to top components: anodized aluminum substrate, copper interconnects, N-type and P-type particles, and 1 mm thick copper sidewalls on three sides of each particle (transparent schematic) for hot injection and current injection. Fig.18 As shown in Figure 2, thicker sidewall metal thicknesses produce higher thermal and electrical conductivities, with 1mm sidewall thickness having the highest power output. In addition, for example, comparing the 0.05mm case at 0.85 and 0.65 coverage to the Fig.10 Higher sidewall coverage yields higher output as shown in comparison with the case of 0.2 mm thick nickel sidewall observed in Figure 5, where metal sidewall coverage is taken as a parameter.

[0077] Figure 7 is an exemplary computational mesh 140 for a thermocouple pair circuit in the case where the sidewall has a gap at the top of the sidewall. The limits of meshing are determined by the thickness aspect ratio of the adjacent components. As previously discussed, there are methods to compensate for these limits by adjusting the thickness and physical properties of the material.

[0078] Figure 8 An exemplary relationship 150 between device power for a thermocouple pair circuit and particle thickness normalized to the power output of a 1 mm thick particle device is shown. Calculations have been derived to provide an analytical solution for the thermocouple pair. These calculations herein confirm those results and provide motivation for increasing power output by an alternative approach, namely including sidewall metal coverage in the packaging of the thermoelectric module.

[0079] Fig. 9 An exemplary normalized maximum power output 160 for a 1 mm thick pellet without metal sidewalls is shown as a function of the amount of sidewalls covered by metal. That is, Fig. 9 The normalized linear maximum power output versus nickel metal sidewall coverage is shown for a 1 mm thick particle relative to a particle without metal sidewalls. In this example, a metal coverage of 0.8 mm (80%) per sidewall was used. The power output is linearly related to the number of sidewalls present on the particle (R 2=1). For the solution of the fixed heat equation, this relationship agrees with the analytical results with similar boundary conditions in a 2D rectangle. In the analytical case, uniform (or non-mixed boundary) conditions are used. Each sidewall can be treated independently of each other since this is a case of fixed heat transfer and the heat injection is linearly additive. Therefore, the power generated through the thermoelectric effect is additive for each sidewall, resulting in a linear relationship of the output power with the number of sidewalls present on the particle. It is worth noting that the computational model results agree with the analytical results even though the boundary conditions in the model are non-uniform because there are gaps in the sidewall metal to avoid shorting between the top and bottom of the particle electrodes. This means that the analytical solution for the temperature field can be solved by separating out the solution for each sidewall and the solution for each portion of the sidewall that is not coated with metal. These results are summarized in Fig.25A and 25B The isotherms from the analysis results are Fig.13 The isotherms are consistent with the calculated results. Note the similarity between the analytical and calculated results, confirming the curvature of the isotherms. The curvature of the isotherms increases the area of ​​the thermoelectric effect, and therefore the power output is linearly related to the number of sidewalls present.

[0080] Fig.10 An exemplary maximum device power output 170 normalized to the maximum power of a particle without metal sidewalls is shown versus nickel metal sidewall coverage for a 1 mm thick particle. Fig.10 An exemplary maximum power output for a thermocouple pair is shown with sidewall metal coverage normalized to the maximum power output without sidewalls, with sidewall metal coverage as a parameter. In this case, the metal thickness is 0.2 mm. This nonlinear behavior shows that the thermal lensing effect is nonlinear with respect to sidewall coverage, which was not shown previously because the previous analytical solution did not use the thermoelectric effect for the solution of the temperature field. The solution for the nonuniform boundary conditions is known. Note that the polynomial used to describe the nonlinear behavior is the sixth power of the sidewall coverage, R 2 is 1.

[0081] Fig.11 An exemplary cross section of the thermal gradient 180 through the center of the particle with sidewall metal is shown, causing a thermal lens with a sidewall thickness of a 0.05 mm hole centered at 0.5 mm of the particle height. The thermal lens exists symmetrically in the upper and lower halves of the particle and produces a dome-shaped isotherm, thereby increasing the effective area of ​​the thermoelectric effect.

[0082] Fig.12 An exemplary cross section of a 100° C. thermal gradient 190 through the center of a particle is shown without sidewall metal, resulting in a planar isotherm.

[0083] Fig.13 One exemplary thermal focus 200 is shown for the case of a 0.2 mm wide hole at the top of a 1 mm sidewall thickness particle. Note that the thermal lensing effect is very strong near the edges.

[0084] Fig.14 An exemplary thermal focus 210 is shown for the case of a 0.05 mm wide hole located at the bottom of a 0.2 mm nickel thickness particle. The isotherm curvature is Fig.13 The isotherm curvature of , in contrast, shows that the isotherm curvature is essentially independent of whether the metallic interstices appear to be located on the hot or cold side of the particle.

[0085] Fig.15A and 15B Exemplary advantages of metal gap locations are shown. For example, Fig.15A The resistive load loss 220 of the thermocouple is compared as a function of the center of a 0.05 mm wide hole on all four particle sidewalls. Fig. 15B Thermoelectric power output 222 is shown. In this example, the particle sidewalls are nickel metal with a thickness of 0.2 mm. The power output of the thermocouple device is a function of the center of the location of the 0.05 mm wide metal holes on all four sidewalls. Note that the maximum power occurs when the holes are located near the top or bottom of the particle, indicating that the thermal lensing effect is strongest when the metal gap is off-center relative to the particle height. In general, the load loss of the thermocouple varies with the center of the 0.05 mm wide holes on all four particle sidewalls.

[0086] Fig.15A Also shown is the variation in actual power output as the center of the 0.05 mm wide gap is located at different positions on the sidewalls on all four particle sidewalls. The power output increases when the metal gap is close to the bottom electrode or the top electrode relative to other locations of the gap. Note that the maximum power occurs when the hole is located near the top or bottom of the particle, indicating that the thermal lensing effect is strongest when the metal gap is off-center relative to the particle height. The resistive power load is positive, opposite to the power generated, while the power generated is negative because power generation is considered to be the opposite of power loss. The curvature of the temperature isotherms is greater for these locations and is very symmetrical in terms of performance at any location. Smaller gaps generally result in higher heat and current injection, resulting in higher power output. Obviously, the computational limits of the gap width are determined by meshing and are physically determined by the actual properties of making the gap on the side of the particle, most likely by laser ablation of the metal film on the particle prior to bonding the TLE.

[0087] Fig.16An exemplary maximum device power output versus external resistive load factor 230 is shown with nickel metal sidewall coverage as a parameter. The peak of each curve is where the resistive load matches the internal resistance of the thermocouple device, where the device includes the particle and the electrical interconnect as part of the internal resistance. The straight line 232 through the peak represents an inverse linear relationship between the maximum device power output and the external resistive load factor, because the internal device resistance decreases with increasing sidewall coverage. Since maximum power occurs when the load matches the internal resistance of the particle, a decrease in the internal device resistance requires that the external match also decrease.

[0088] Fig.17 An exemplary parametric relationship 240 between normalized maximum power output and metal sidewall coverage for a thermocouple pair with metal thickness as a parameter is shown. Copper metal sidewall coverage is located on all four sidewalls of each particle of the thermocouple pair, with metal sidewall thickness as a parameter ranging from 0.05 mm to 0.2 mm. The thermal lensing effect is strongest at a thickness of 0.20 mm. Increases in metal coverage and thickness are accompanied by increases in thermal conductivity through the metal sidewall layer, and therefore increase heat injection, which in turn increases thermal focusing. Therefore, increasing either metal coverage or metal thickness increases device power output.

[0089] Fig.18 Exemplary current-voltage load lines 250 are shown for three thermocouple pair devices 251, 252, and 253 with metal sidewall coverage on all four sidewalls, metal sidewall thicknesses of 0.05 mm and 1 mm, and metal sidewall coverage at 0.65 and 0.85 portions of the particle height. Compared to the 0.05 mm thick sidewall, the 1 mm thick sidewall is expected to produce more power due to increased thermal conductivity. Comparison between the 0.05 mm and 0.85 portions at the 0.05 mm load line shows that there is a crossover point at higher voltages because the increased metal coverage of the 0.85 mm housing reduces the open circuit voltage by shorting the device portion along the sidewalls. However, at higher currents, the thermal focusing effect causes more short circuit current, and the maximum power (which occurs at 1 / 2 short circuit current and 1 / 2 open circuit voltage) is slightly higher in the 0.85 case than in the 0.65 case. These two load lines indicate the sensitivity of the maximum power to metal coverage.

[0090] Fig.19 Show Fig.18An exemplary current-voltage load line 260 for three thermocouple pair devices 251, 252, and 253 in FIG. 2 with metal sidewall coverage on all four sidewalls, metal sidewall thickness of 0.05 mm and 1 mm, and metal sidewall coverage at 0.65 and 0.85 of the particle height. The relationship between device power and resistive load is a parameter in the case of metal sidewall coverage. The peak is where the resistive load matches the internal resistance of the thermocouple device. The output power indicates that the coverage of 0.85 is greater than the coverage of 0.5, and the crossover voltage is 0.25 volts.

[0091] Fig. 20 Exemplary current-voltage load lines 270 are shown at four temperatures (50° C., 100° C., 150° C., 200° C.) for three 1 mm thick sidewall cases. The trends are expected and further confirm the computational model.

[0092] Fig.21 An exemplary semiconductor particle subcomponent 280 of a TETC is shown. For example, Fig.21 An exemplary thin metallization (253) particle is shown ready for bonding to a TLE component. The four features are a thermoelectric semiconductor particle 281, a primary metal layer 282 for bonding and / or diffusion barrier (titanium, tungsten, Ni-P

[20] , chromium, active brazing alloy, etc.), a solderable and non-oxidizable metal layer 283 (gold, palladium, and Ni-P), and a gap 284 (e.g., discontinuity) in the metal layer 283 from the surface of the metal 282 to the semiconductor material of the particle 281. Any number of thin film metal layers, such as gold, silver, Ni-P, etc., may be used depending on the final layer that provides a solderable surface. Typically, the metal gap 284 is to interrupt the electrical continuity from the top electrode to the bottom electrode on the particle sidewall.

[0093] Fig. 22 An exemplary finished TETC component 290 is shown with details of the various layers. These features include an N-type or P-type semiconductor particle 281, material removed by multi-layer deposition to form a gap 284 (i.e., a discontinuity) in the metal surface 282 / 283 through the semiconductor surface of the particle 281, and a bonding material 291 such as solder (Sn-Ag-Cu, In-Ag

[21] , In-Sn) that thermally and electrically bonds the outer surface of the particle 281 to the inner surface of the subcomponent TLE 292, except where the discontinuous metal gap 284 is placed. Features 282 and 283 are Fig.21 The films discussed in , however any number of film layers may be used to meet the requirements.

[0094] Fig.23An exemplary detailed cross section of two TETC components mounted in a thermoelectric module 300 as an application example is shown. In this packaging option, there are two separate metal interconnects (submounts) bonded to the solder layer 291, which is also used to bond the particles 281 to the substrate 304. The upper metal substrate has square through holes to provide a thermal lens for the metallized semiconductor particle layer.

[0095] Fig.24 An exemplary detailed cross section of two TETC components installed in a thermoelectric module 300 as an application example is shown. This packaging option uses a stamped metal substrate to provide a thermal lens for the particles 281.

[0096] Fig.25A and 25B An exemplary comparison of two visualizations of isotherms calculated by Fourier method using separation of variables is shown, and the isotherms are identical to the isotherms determined by the computational method herein.

[0097] Manufacturing aspects of thermally enhanced thermoelectric components (TETCs)

[0098] This paper proposes a method to increase the output power of thermoelectric generator devices by a significant factor by improving the electrode geometry of the semiconductor particle components used for thermoelectric module assembly. This paper proposes to form the metal sidewall as a subcomponent in a separate manufacturing step and then join it to the pre-metallized semiconductor particles by solder bonding. The two subcomponents joined together form a new electronic component for high-speed packaging surface mount technology. This method is not suitable for the cooling mode of thermoelectric modules because the Peltier effect and the Seebeck effect are opposite (reverse) currents. The influence of the thermal lens electrode on the Peltier operation mode causes a slight decrease in the performance coefficient in the cooling mode.

[0099] In the case of using metal on the sidewalls, the sidewalls have holes or gaps 284 that interrupt the electrical continuity between the top and bottom electrodes of the particle 281 to prevent electrical shorting. Such holes can be formed by laser ablation along the sidewalls after the thin film of the particle 281 is metallized. The hole width can be as narrow as 50 microns or less, or to a practical limit. When using small holes in the sidewall metal, there may be two focusing effects depending on the location of the holes. The narrow holes around the particles located in the center of the sidewall and parallel to the top surface produce two thermal focusing effects, one near the top side of the particle and the other near the bottom side of the particle. The center of the hole near the top or bottom of the particle causes higher power output compared to other locations of the hole.

[0100] The interruption of the electrical continuity of the side wall can also be achieved by chamfering the four edges of the top or bottom of the particle.

[0101] The fabrication of a thermally enhanced particle (TEP) typically includes (1) a lens electrode (TLE) component, (2) a metallized particle (281, 282, 283) having an electrical continuity break (i.e., gap 284) on all sidewalls, and / or (3) solder for bonding the TLE and the particle. In a practical sense, fabrication can be accomplished in a two-step process. First, a solderable surface on each subcomponent can be used to form a bond by solder bonding. Thin film methods such as electroplating or chemical plating can be used to coat the particle with various metals to form an adhesion layer, diffusion barrier layer, and solderable layer in various methods. The final metal layer typically has a solderable metal to bond to the TLE, and the solderable metal is preferably made of copper, nickel, silver, or any metal with a solderable finish. An appropriate amount of solder is dispensed into the TLE or a flux-free preform of appropriate thickness is inserted into the bottom of the TLE, and then the particle is placed in the TLE. After the solder at the bottom and sidewalls of the particle 281 is reflowed, the particle and TLE are bonded together. Preferably a solder having a higher melting temperature than the solder used to join the remaining package components is used.In this way, an electronic component is manufactured for assembly, wherein high speed pick and place methods can be used.

[0102] This suggests that for a single thermocouple pair in power generation mode, an increase in device power output can be achieved by performing both thermal and electrical injection on the sidewalls of the particle. The following scenarios can be examined: (1) the effect of gradually increasing the metallized sidewalls to the same thickness until the sidewalls have the same thickness of metal (linearly related to the number of sidewalls), (2) varying the sidewall height from 0 height to about 0.95 of the particle thickness (a non-linear effect with increasing metal sidewall height), and / or (3) varying the position of the 0.050 mm gap in the sidewall metal. Each variation has a unique effect in increasing device power output via thermal focusing. In fact, this suggests that, contrary to common practice in the fabrication of thermoelectric generation devices (e.g., where partial electrical shorting along the sidewalls is expected to reduce device power output), it is advantageous to partially metallize the sidewalls of the semiconductor particle. Electrical shorting is avoided by leaving a narrow gap or gap in the metallization of all the sidewalls between the top and bottom metal electrodes. This may result in a significant increase in the number of cases where thermoelectric generation is achieved via thermal focusing or lensing. Results are also presented based on computational analysis of metallization gap width thickness of 50 microns and uniform metallization thickness of 0.05-1 mm on all four sidewalls (e.g., bismuth selenium telluride and bismuth antimony telluride thermoelectric particles), and measured physical properties. Gaps 284 that interrupt electrical continuity are symmetrically located around particle 281.

[0103] A method of increasing the output power of a thermoelectric generator by a significant factor comprises improving the electrode geometry of the semiconductor particles 281 used in the assembly of components of the thermoelectric module. It is suggested to use a new component that can be used in the surface mount component assembly of the thermoelectric module. The increase in power output is achieved by heat injection and electrical injection into the semiconductor particle body through the sidewall of the particle 281. In fact, in contrast to common manufacturing methods, it is advantageous to metallize the sidewalls of the semiconductor particles 281. In addition, leaving a small gap 284 or gap in the metallization of the sidewall between the top metal electrode and the bottom metal electrode allows the thermoelectric power generation significantly increased by the thermal lens electrode. The results are presented based on a computational analysis of the metallization gap width thickness of 50 microns on the sidewalls of all four telluride-based thermoelectric particles that are symmetrically positioned.

[0104] Fig.21 An exemplary cross-sectional view of a particle 281 subcomponent for TETC is shown. Typically, particles can be electroplated or electroless plating methods, because these methods can be easily carried out in large quantities in modern electroplating companies. Several layers (e.g., layers 282 and 283) can be electroplated in sequence to meet adhesion, diffusion barrier layers, and solderable layers to join to other components. As described in the previous section, the number of layers can generally be 3 to 4 layers. The method of depositing these layers has physical vapor deposition, explosive lamination, electroplating, electroless plating, high-pressure lamination or pressurization. Once the metal layer has been deposited on N-type and P-type particles, a gap 284 in the metal layer is generated on all four sidewalls of the semiconductor particle 281 to interrupt electrical continuity along the particle sidewall. This operation may include a grinder, a special saw, a laser, an abrasive wire, or an EDM technology. As described above, it is important to remove the sidewall metal at an appropriate height along the particle sidewall, and the gap 284 is continuous along all sidewalls and is preferably at the same height on all four sidewalls.

[0105] As discussed above, Fig. 22 An exemplary completed TETC component is shown with details of the various layers and using the Fig.21The same aspects of the semiconductor particles just described in . The method of manufacturing the metal TLE 292 (for example, shaped like a square metal cup) can be embodied by a variety of techniques. Techniques such as stamping, forming, electroforming, template printing, molding and casting can be used. The TLE is attached to the N-type particles and the P-type particles by the conventional or special solder described in the previous section, and the solder is reflowed at different temperatures, which is different from the temperature of the solder that attaches the TLE to the metal substrate (electrical interconnect). The difference in reflow temperature is usually required to allow multi-level assembly. Candidate solders include transient liquid phase alloys. These alloys contain pure metals (In, Sn) that melt at low temperatures and metals (Ag, Cu) that melt at high temperatures. Once melting begins, intermediates are formed in the process and the solder begins to freeze. Once the intermediate compound is formed, the next melting temperature is relatively high (650°C for In-Ag). Therefore, more conventional alloys such as Sn-Ag-Cu (SAC) can be used in the rest of the assembly to join the components. For these types of in-situ alloys, one embodiment includes using Ag-Sn to keep material costs low. Additionally, more conventional solders may be used, preferably lead-free solder alloys.

[0106] exist Fig. 22 In the embodiment, an N or P type semiconductor particle subcomponent has material 283 / 284 removed by multi-layer deposition to create a discontinuity in the metal surface through the semiconductor surface. The solder layer 291 (Sn-Ag-Cu, In-Ag

[21] , In-Sn, Ag-Sn) discussed above is used to bond the metalized particle and the TLE 292 surrounding the particle surface on all four sidewalls (e.g., up to the height of the discontinuous metal gap or slightly below the height) and the bonding material thermally and electrically bonded to the particle outer surface and the TLE subcomponent inner surface. The metal layer 282 / 283 is again shown in the TLE 292, except where the discontinuous metal gap 284 is placed. In this embodiment, the metal layer 282 / 283 is Fig.21 The films discussed in , however any number of film layers may be used to meet the requirements.

[0107] Fig.23A cross section of one type of application of a TETC 300 is shown using a two-piece assembly (i.e., TETC-2L) in which the two substrates are matched in lateral dimensions so that one substrate can be mounted on top of the other with matching substrate perimeters. In other words, the substrates are typically the same part and when stacked vertically, the two substrates are intended to be a single unit for TETC component placement. The bottom substrate 304 is solid, while the top substrate 306 has two square holes (vias) that pass through the thickness of the substrate. The square holes in the top substrate can be manufactured by processes such as laser cutting, stamping, casting, molding, machining, and hand cutting. These square holes provide heat to the thermal lenses of the N-type and P-type particles 281 after being bonded to the substrate by solder 291. As Fig.21 and 22 The previous features described in have been improved to provide a dual TLE component that provides a thermal lens for two semiconductor particles 281. The lower component 304 of the two-piece TLE supports the upper portion of the TLE component. Therefore, for component 306, the improved substrate has a dual thermal lens electrode component or TETC-2L with two substrate layers.

[0108] Fig.24 Yet another method of applying thermal lensing to particles 281 is shown. As with the TECT-2L, the TLE subassembly is modified to contain two particles 281. For this packaging option, the TLE is modified in the same manner as the TLEC-2L through processes such as laser cutting, stamping, casting, molding, machining, and hand cutting. Fig.23 As shown, in Fig.24 Use as Fig.21 and 22 The previous features described. Fig.24 In FIG. 1 , portions of features 306 and 304 have been modified to provide a dual TLE component that uses a metal substrate to provide thermal lenses for two semiconductor particles. Thus, in this component, the modified substrate is a dual thermal lens electrode component with one substrate layer, or TETC-1L.

[0109] In any or all of the above examples, the metal subcomponents of the TETC have relatively high thermal and electrical conductivity (eg, nickel-plated copper).

[0110] Fig.23 Several exemplary features that can be used in manufacturing are shown. For example, in one embodiment, particle 281 is a thermoelectric semiconductor component that has been metallized using multiple layers including feature 282, a diffusion barrier layer, and layer 283 (e.g., a noble metal on top of the particle 281 substrate to prevent oxidation). The manufacturing methods used to make this multi-layer deposition on the particle can include physical vapor deposition (PVD), explosive lamination, spraying, electroplating, chemical plating, and high temperature lamination.

[0111] Gap 284 includes a gap in which metal removal is performed to generate heat and electrical interruptions in the peripheral edge of the particle to avoid short circuits. This interruption provides a thermal lens effect to increase power output. Some manufacturing methods for creating features in gap 284 include wire discharge machining (EDM), abrasive wire cutting, metallization process masking, abrasive saw cutting and laser etching. Then, the metallized particle 281 can be placed in a two-piece thermal lens device consisting of a solid component 304 and a double cavity implemented by component 306. Components 304 and 306 can be manufactured by stamping, 3D printing, laser cutting, water jet cutting, wire EDM, CNC machining or casting. Components 304 and 306 can also be manufactured into an integral piece by 3D printing, stamping and CNC machining. Components 304 and 306 can include copper and be electroplated with nickel to prevent oxidation. The cavity in component 306 usually matches the shape of particle 281 (for example, the cavity is slightly larger than particle 281 to provide space for bonding material 291). Component 304 may include a cavity that is attached to solid piece component 306 by heat welding, ultrasonic welding, explosive lamination, high temperature pressurization, and thermally and electrically compatible adhesives. Thus, components 304 and 306 become a unitary component with two cavities so that finished metallization particles 281 with gaps 284 can be placed and attached to components 304 and 306 by a curing process specific to the bonding method of the solder bonding material.

[0112] The inner square cavities formed by the holes in component 306 can be coated with solder (e.g., by dispensing, stencil printing, and mask spraying) so that particles 281 (and layers 282 and 283) can be attached to the component. Any or all of the components can be placed in tape and reel, vibrating bowls, tubes, or Joint Electron Device Engineering Council (JEDEC) trays for high-speed placement by a robotic system. A suitable thermal adhesive can be printed using a stencil to clamp components 304 and 306 during high-speed robotic pick and place. This process can be repeated many times to fill the package board and build large industrial modules or sleeves. Then, P-type and N-type particles 281 can be placed in these cavities using a high-speed robotic system, where the sidewall height of component 306 matches the height of the gap 284 gap. The thermal lens assembly 300 can be repeated many times on a module package board (e.g., copper-clad alumina, anodized aluminum, or other suitable flat substrate) so that the elements of the lower half of the sleeve (or module) surround the particles 281. The top plate with metal interconnects (e.g., layer 304) installed can be positioned and bonded in the appropriate position and number to complete the series circuit between the components on the bottom plate. Solder can be printed on the top of the particles 281 on the bottom plate to bond the particles to the package plate. This flip-top assembly can then be installed in an aluminum holder that applies slight pressure to the assembled module. The assembly can then be heat treated by an intermittent furnace, a conveyor reflow oven, ultraviolet (UV) curing, and / or an ultrasonic welding system to complete the process of material curing and solder reflow.

Claims

1. A thermoelectric device, comprising: a particle having a sidewall comprising a semiconductor material; as well as a first metal layer surrounding a first portion of the particle; a second metal layer surrounding a second portion of the particle, wherein the first metal layer and the second metal layer are disposed proximate to each other around a perimeter of the particle, wherein the particle is exposed at a gap formed between the first metal layer and the second metal layer, wherein the gap is continuously formed around the perimeter, and wherein the gap is disposed at a sidewall height around the particle to provide a nonlinear effect on a power output of the thermoelectric device by modifying an isotherm surface curvature within the particle; as well as A metal container thermally and electrically bonded to the particle, wherein the metal container provides a structure with a thermal lens effect, wherein the first metal layer and the particle include inclined edges near the perimeter of the particle to electrically isolate the first metal layer and the second metal layer from each other.

2. The thermoelectric device according to claim 1, wherein: The isothermal surface curvature within the particle can be used to increase the effective surface area for thermoelectric effects within the volume of the particle via heat injection through the sidewalls.

3. The thermoelectric device according to claim 1, wherein: The first metal layer and the second metal layer include a higher thermal conductivity than the particles.

4. The thermoelectric device according to claim 3, wherein: At least one of the first metal layer and the second metal layer includes copper.

5. The thermoelectric device according to claim 1, wherein: At least the particles and the second metal layer are configured into a shape that can be used to increase a thermal lens effect of the thermoelectric device.

6. The thermoelectric device according to claim 5, wherein: The shape is a cube.

7. The thermoelectric device according to claim 5, wherein: The shape is a cylinder.

8. The thermoelectric device according to claim 1, wherein: The first metal layer and the second metal layer are electrically isolated from each other.

9. A method for manufacturing the thermoelectric device according to claim 1, comprising: metallizing the plurality of semiconductor particles using one or more metal layers; removing a portion of the metal layer around a perimeter of each of the plurality of semiconductor particles to form a gap in the one or more metal layers on each of the plurality of semiconductor particles, the gap exposing the semiconductor particle; forming a substrate with a plurality of cups formed of copper; electroplating the cup with nickel; coating a portion of the cup with solder; placing a semiconductor grain of the plurality of semiconductor grains in each of the cups such that a sidewall height of each cup matches a gap position of each semiconductor grain to provide a nonlinear effect on power output of the thermoelectric device by modifying isothermal surface curvature within each of the plurality of semiconductor grains; The solder is cured to adhere the plurality of semiconductor particles to the cup to form the thermoelectric device.

10. The method according to claim 9, further comprising: The isotherm surface curvature within each of the plurality of semiconductor grains is configured to increase an effective surface area for thermoelectric effect within a volume of each of the plurality of semiconductor grains through thermal implantation of the sidewalls of each of the plurality of semiconductor grains.

11. The method according to claim 9, further comprising: The metal layer is configured to have a higher thermal conductivity than each of the plurality of semiconductor particles.

12. The method according to claim 11, further comprising: At least one of the metal layers is configured as copper.

13. The method according to claim 9, further comprising: Each of the plurality of semiconductor particles is configured into a shape that can be used to increase a thermal lens effect of the thermoelectric device. The method of claim 13 , wherein the shape is a cube.

15. The method of claim 13, wherein the shape is a cylinder.

16. The method of claim 9, further comprising: Remaining portions of the metal layer of each of the plurality of semiconductor particles are electrically isolated from each other by removing a portion of the metal layer surrounding a perimeter of each of the plurality of semiconductor particles.

17. The method of claim 9, further comprising: Each of the plurality of semiconductor particles is configured to include a sloped edge proximate the perimeter of the particle so that remaining portions of the metal layer of each of the plurality of semiconductor particles produced by removing a portion of the metal layer around the perimeter of each of the plurality of semiconductor particles are electrically isolated from each other.

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