JP2006294935A - High efficiency low loss thermoelectric module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a Joule's heat loss to achieve high efficiency and a low loss in a thermoelectric module constructed of a thermoelectric semiconductor element exhibiting a Seebeck effect and a Peltier effect and electrodes at both ends thereof. <P>SOLUTION: In the thermoelectric semiconductor element, the electrodes sandwiches or surrounds it from its ends to its side face to increase the contact area between the electrodes and the thermoelectric semiconductor element unit. Namely, the middle portion of the element is constricted like a bobbin to reduce heat transmission, and a heat shielding sheet is provided as needed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a high-efficiency, low-loss thermoelectric module that uses the thermoelectric effect in a range from a relatively low temperature (normal temperature range) to a high temperature close to about 800 ° C. The thermoelectric effect is a general term for the Seebeck effect, the Peltier effect, or the Thomson effect of a thermoelectric semiconductor. Therefore, the present invention belongs to the technical field of a thermoelectric semiconductor module or a power generation device or a cooling / heating device using the thermoelectric semiconductor module. .

FIG. 10 shows an existing thermoelectric device. When a temperature difference is given between both ends of the N-type thermoelectric semiconductor element, majority carriers diffuse to the low temperature side, and an electric field is generated from the high temperature side to the low temperature side. When the carrier moves, equilibrium is maintained and a potential difference is generated between both ends of the element. Here, when a load is connected to both ends of the thermoelectric semiconductor element, a current flows through the load, and a potential difference is created between both ends of the load. On the other hand, the heat that has entered the connection point on the high temperature side travels along the lead wire and escapes. In a P-type thermoelectric semiconductor element, the thermal activation power is opposite to the majority carrier movement of the N-type thermoelectric semiconductor element. The P-type and N-type thermoelectric semiconductors can be connected so as to be electrically connected in series and thermally connected in parallel by configuring them in a π structure.

The fact that the Seebeck effect model of a thermoelectric semiconductor element is basically a π structure will be described with reference to FIG. As shown in the figure, as a basic form, a “π structure” is formed from a P-type thermoelectric semiconductor element, an N-type thermoelectric semiconductor element, and electrodes joined to them. A thermoelectric semiconductor module having a π structure generates thermoelectric power by the Seebeck effect when a temperature difference (ΔT) is applied between the electrodes at both ends, and electrons are generated by the Peltier effect when current is passed through the thermoelectric semiconductor element. It moves to create an endothermic (low temperature) side and a heat dissipation (high temperature) side. According to the π structure, a P-type thermoelectric semiconductor element, an N-type thermoelectric semiconductor element, and an electrode are connected in pairs or alternately in pairs, electrically in series, and the low temperature side and the high temperature side are heated up and down. Are formed in parallel. If thermal energy (temperature difference ΔT) is supplied to the low temperature side and the high temperature side, a power generator is obtained as shown in FIG. 9A due to the Seebeck effect. If power is supplied to an electrically serial circuit, a cooling (heat absorption) device or a heating (heat radiation) device is obtained by the Peltier effect as shown in FIG. 9B.

In a circuit where a pair of P-type and N-type thermoelectric semiconductors are joined, when the π structure is formed via a dissimilar metal (copper electrode) having low electrical resistance and high thermal conductivity, the temperature of the electrodes is determined by the thermoelectric semiconductor element. The moving direction of majority carriers generated in the P-type and N-type thermoelectric semiconductors is the same as the junction. This means that when a π structure is formed so that it is electrically in series and thermally parallel, the heat transfer related to Joule heat and heat conduction is minimized, and loss due to heat dissipation is eliminated. Means.

The π structure constituting the thermoelectric device includes a standard product in which 127 pairs of P / N thermoelectric semiconductor elements (dice type, cylinder, etc.) are arranged as a π structure unit between 4 cm square plates.

Various studies have been made to improve the performance of thermoelectric elements. However, the results are not ridiculous, and it is said that there is no choice but to improve the Z value, which is a factor representing the characteristics of thermoelectric materials. In fact, proposals for thermoelectric semiconductor materials have also been made. However, the Z value is proportional to the electrical conductivity and inversely proportional to the thermal conductivity. In general, materials with high electrical conductivity have the property of high thermal conductivity. This makes it difficult to set the Z value to a desired value, and no significant improvement has been observed so far.

At present, there are few Seebeck thermoelectric generators for low temperature regions. Many researches have been conducted for the purpose of using the steel under heat in the steelworks and power plants under extremely high heat.

In order to improve the efficiency of the thermoelectric effect while taking advantage of the characteristics of the thermoelectric semiconductor, the present applicant has previously developed an improved technology that improves the total power generation by folding a thin layer thermoelectric element into a spiral or zigzag and integrating it into a three-dimensional structure. Proposed (Patent Document 1). The improved technique is not limited to a high density integrated thin layer element, but can be generalized. On the other hand, the point which should be improved also to each thermoelectric element was discovered. The first is the bonding structure of the electrode or the electrode and the thermoelectric element, and the second is the structure of the thermoelectric semiconductor itself. The present invention has a problem in that the junction area between the thermoelectric semiconductor element and the electrode is widened to increase the current density, and the thermoelectric semiconductor element structure is a structure with low Joule loss, specifically Provide a structure that prevents loss of heat flow.
Application for Japanese Patent Application No. 2004-160886 Japanese Patent Laid-Open No. 08-228027 2001-156343

An object of the present invention is to provide a high-efficiency, low-loss thermoelectric module that can be used from a relatively low temperature range to a high temperature range close to about 800 ° C.

In order to maximize the power generation efficiency of the length, width, and shape of a thermoelectric element, for example, a π-structure thermoelectric element, a direction in which the internal resistance of the module is set low can be considered. If the internal resistance of the module is set low, the power generation appears to improve, but at the same time, losses due to Joule heat and heat conduction must be considered. Joule heat is generated when an electric current is passed through a substance having electrical resistance, and heat conduction is caused to flow through the element when there is a temperature gradient in the thermoelectric element. Seebeck effect, Peltier effect and Thomson effect are reversible phenomena, but Joule heat and heat conduction are irreversible phenomena. The heat balance relationship as a thermoelectric module is a combined action of a reversible phenomenon and an irreversible phenomenon, and the portion of the irreversible phenomenon tends to be a factor that reduces the Seebeck effect and the Peltier effect.

The main object of the present invention is to provide an improved electrode configuration, thermoelectric semiconductor device configuration, and contact relationship with the electrode.

Still another object of the present invention is to provide a thermoelectric semiconductor element having a structure for preventing loss due to heat flow, particularly a module having a π structure.

The present invention relates to a high-efficiency low-loss thermoelectric module that solves the above-described problems. The semiconductor may be a prism (dice shape) or a cylinder, or may be a thin layer element. A single thermoelectric element can achieve a predetermined effect, but in particular, the effect can be expected by constituting a plurality of π structures.

In the present invention, as a main problem, the contact area between the thermoelectric semiconductor element and the electrode is substantially increased. Specifically, the electrode area is increased from the end face of the thermoelectric semiconductor element to the side face of the element, and is provided so as to be overlapped or surrounded by a cover, so that the electrode area is substantially increased. Corresponding free carriers are formed by the Seebeck effect, resulting in a larger thermoelectromotive force. Moreover, the substantial contact area between the thermoelectric semiconductor element and the electrode can be widened by forming the surface of the thermoelectric semiconductor to which the electrode is bonded into a corrugated or perforated structure instead of a flat surface.

When the electrode is surrounded to the side surface of the semiconductor element, if heat easily moves from the hot high temperature side to the low temperature side around the thermoelectric semiconductor element, the efficiency may be lowered in both the power generation device and the heating / cooling device. . Therefore, each thermoelectric semiconductor element is particularly required to have a structure that insulates the low temperature side and the high temperature side. Although a vacuum structure around the module is effective, the vacuum structure increases costs. Therefore, in the present invention, a heat-flow blocking sheet is attached to the central portion of the thermoelectric semiconductor, the intermediate portion between the high temperature side and the low temperature side. A vacuum structure is not required, heat flow between the electrodes can be prevented, and heat transfer can be limited. There is a prior art provided with a partition plate (Patent Documents 2 and 3). Although these and the present invention look similar in structure, in the prior art, the partition plate is provided to mechanically support the semiconductor element. On the other hand, the present invention is characterized in that the heat transfer when the electrode in the thermoelectric semiconductor element is enclosed is further blocked by the heat insulating action of the partition plate. Of course, it can also be used as a mechanical support.

Next, taking a popular 4040 size thermoelectric module as an example, Joule loss is determined when the electrode is formed so as to surround the end surface from the high temperature side or the low temperature side of the cylindrical thermoelectric semiconductor element.

The amount of power generated when the electrodes are extended and joined so as to cover the side surfaces of the thermoelectric element and the electrode area = (element cross-sectional area S ₁ + side electrode area S ₂ ) will be considered.
Seebeck coefficient (electromotive voltage per degree of temperature difference) α = 2.25 × 10 ⁻⁴ V / K
Electrical resistivity ρ = 1.12 × 10 ⁻⁵ Ωm
Number of thermoelectric semiconductor element pairs: P / N = 127
Element cross-sectional area S ₁ = (1.8 × 10 ⁻³ / 2) ² π = 2.54 × 10 ⁻⁶ m ²
Side electrode area S ₂ = 0.5 × 10 ⁻³ × 1.8 × 10 ⁻³ π
= 2.83 × 10 ⁻⁶ m ²
Element length L = 1.8mm
Element length L ₂ = 1.8− (0.5 / 2) × 2 = 1.3 mm
When the effective element length L ₂ = 1.3 mm, the total resistance of the module is R _{em (S1 + S2)} = ρ × 127 × 2 × 1.3 / (S ₁ + S ₂ )
= 1.12 × 10 ⁻⁵ × 127 × 2 × (1.3 × 10 ⁻³ ) / (5.37 × 10 ⁻⁶ )
= 0.69Ω
Therefore, when the temperature difference ΔTj = 30K and L = 1.3 mm, the power generation amount of the module is
P _em = (α × 127 × 2 × 30) ² /0.69×(1/4)
= 1.058W (A)
Is obtained.

On the other hand, when the temperature difference ΔTj = 30K, and L = 1.8 mm,
The total resistance of the module is R _em = 2.84 × 10 ⁻⁵ × (1.8 × 10 ⁻³ ) / (5.37 × 10 ⁻⁶ )
= 0.952Ω
Therefore, the power generation amount of the module is P _em = 2.92 / (0.952 × 4)
= 0.77W (B)

On the other hand, if the electrode area = element cross-sectional area (conventional form in which no electrode is covered), the total resistance of the module is
R _em = 1.12 × 10 ⁻⁵ × 127 × 2 × (1.8 × 10 ⁻³ ) / (2.54 × 10 ⁻⁶ )
= 2.10Ω
When ΔTj = 30K, the power generation amount is
P _em = 292 / (2.10 × 4) = 0.35W (C)
Therefore, it can be seen that the power generation amount can be improved as shown in FIGS.

The high-efficiency low-loss thermoelectric module of the present invention preferably has a structure having a dot hole at an arbitrary position of the thermoelectric semiconductor element, so that the resistance of the thermoelectric semiconductor element unit can be adjusted.

Another major feature of the high-efficiency low-loss thermoelectric module of the present invention is that the surface of the thermoelectric semiconductor element is non-planar, that is, has a corrugated, comb-shaped, or dot-hole structure at the interface between the thermoelectric semiconductor element and the electrode. Thus, the contact area can be substantially enlarged and the current density can be increased. Furthermore, the resistance value of the thermoelectric semiconductor element can be arbitrarily adjusted by changing a non-planar shape such as a dot hole or a slit in the manufacturing process.

In the high-efficiency low-loss thermoelectric module of the present invention, it is further proposed to form a constricted structure at the intermediate portion between the high temperature side and the low temperature side of the thermoelectric semiconductor element. At this time, the effect of the heat transfer generated according to the temperature difference between both sides will be considered approximately.

In the present invention, a case where a constriction is formed at the center of the thermoelectric module will be considered. The constriction creates a temperature gradient in the lengthwise direction. Find the passage of heat against the temperature gradient. Heat flows through the thermoelectric semiconductor element. The amount of heat αk that passes through the unit cross-sectional area perpendicular to the temperature gradient at this time within the unit time is expressed by the following equation (1).
ακ = κ × dT / dL (1)
κ: Thermal conductivity (w / mK)
The amount of heat Kω that flows through per unit time per 1 K (Kelvin), where L is the length in a direction with a temperature gradient, is expressed by Equation (2).
Kω = κ × S / L (2)
S: total cross-sectional area, κ: thermal conductivity (w / mK), L: heat transfer distance At this time, the thermal resistance W is represented by the reciprocal of Kω.
W = 1 / Kω (3)

As a model, a central portion of a thermoelectric semiconductor element having a circular cross section having a length L is formed as a conical constriction structure having a predetermined size. The amount of heat that flows per unit time per 1 K (Kelvin) with respect to the diameter Φn of the constricted portion and the electric resistance with respect to the average constricted diameter r are obtained, and the amount of power generation of 4040 size (127 pairs) is obtained. Since the volume at the constriction diameter Φn is twice that of the truncated cone V (base D, upper side δ, height h),
2V = [(π / 12) × h (D ² + δ ² + δ × D)] × 2 (4)
From the volume of the above equation (4), when L = 1.8 mm, the average radius r of the constriction Φn is
From r ² πL = 2V r = SQRT (2V / πL) (mm) (5)
(SQRT: √)
From equation (2), the heat flow rate per unit time per 1K is Wф _n = κ × π / L (W / K) (6)

When the temperature difference ΔT = 30 ° C., the heat-transfer flow rate is as follows: W × _n × 30 = 30 × (κ × r ² π / L) (w) (7)
The electric resistance of the thermoelectric semiconductor element is obtained from the average radius, and the power generation amount of 127 pairs is obtained.
The electrical resistance R of one element is R = ρ × L / S (8)
ρ (electric resistivity) = 1.15 × 10 ⁻⁵ (Ωm)
The electrical resistance R _em of the 127 pair module is
R _em = R × 127 × 2 (Ω) (9)
The power generation amount P _w ф _n as a 127-pair module is
P _w ф _n = (127 × 2 × ΔT) ² / R _em × (1/4) (10)
It is represented by here,
α (Seebeck coefficient) = 1.25 × 10 ⁻⁴ (V / K)
ΔT (temperature difference) = 30 ° C.
R _em (Electric resistance of 127 pairs of modules)

From the above calculation, the temperature difference ΔT = 30 ° C. and the value for 127 pairs of modules are shown in [Table 1]. Further, from Equation (7), Equation (9), and Equation (10), the heat flow rate and power generation amount with respect to the temperature difference (ΔT) of the 127 pairs of modules are expressed by the constriction diameter Φn = 1.3 mm, 1.5 mm, 1 .8 mm is shown in [Table 2].

When the constriction is formed from 1.8 mm to 1.5 mm, a reduction of about 15% in heat flow can be expected, but at the same time, the amount of power generation is also reduced. Thus, if a heat-through prevention sheet is provided in the middle part of the thermoelectric semiconductor, an intermediate part between the high-temperature side and the low-temperature side, the transfer of heat can be considerably limited without using a vacuum structure. The same partition plate is used in the above-mentioned Patent Document 2 and the like, and there is a place similar in structure at first glance. However, in Patent Document 2, the partition plate mechanically supports the semiconductor element. In this invention, the thermal disadvantage in the electrode of a covering structure can be improved with the heat insulation effect | action of a partition plate. In other words, the synergistic effect of the decrease in heat flow due to the constriction structure and the decrease in heat flow due to the sheet can be expected to have a greater effect of reducing the loss of heat flow.

The fact that the contact area with the thermoelectric semiconductor element is substantially enlarged by covering the electrodes has the effect of increasing the current density. Further, the resistance value of the thermoelectric semiconductor element can be arbitrarily adjusted by changing the size of the bonding surface between the electrode and the semiconductor element by providing a non-planar shape, for example, a dot hole or a slit.

In the high-efficiency low-loss thermoelectric module of the present invention, the constriction structure of the thermoelectric semiconductor element makes it difficult for an undesired heat flow to occur between the high temperature side and the low temperature side. This effectively solves the problem of reducing the heat flow especially.

Providing a heat-through prevention sheet between the high-temperature side and the low-temperature side improves loss due to wasteful flow of heat. In addition, a vacuum structure is not necessary, and costs can be reduced.

The best mode for carrying out the high-efficiency low-loss thermoelectric semiconductor module of the present invention is a unit formed by a thermoelectric semiconductor element and electrodes bonded to the low-temperature side and the high-temperature side at both ends thereof, preferably P-type In the thermoelectric semiconductor module having one or a plurality of π-structure units composed of N-type thermoelectric semiconductor elements, the electrodes are formed from the end faces of the thermoelectric semiconductor elements to the side surfaces in order to substantially increase the contact area between the thermoelectric semiconductor elements and the electrodes. To sandwich or surround the thermoelectric semiconductor element. That is, the current density is increased by substantially widening the area where the thermoelectric semiconductor element and the electrode are in contact with each other. The thermoelectric semiconductor element may be a cylinder or a prism (dice type), but may be a thin layer (thin film or thick film).

The size of the cross section of the low temperature side and the high temperature side of both ends of the thermoelectric semiconductor element is larger, and the size of the cross section between the low temperature side and the high temperature side of the thermoelectric semiconductor element is smaller, and the pinned neck structure is formed as a whole. A high-efficiency, low-loss thermoelectric semiconductor module is desirable. The constriction structure can reduce the heat flow between the low temperature side and the high temperature side of the thermoelectric semiconductor element.

Furthermore, a part or all of the periphery of the module can be sealed with a heat insulating, electrically insulating, and moisture proof material to further reduce the heat flow loss. The thermoelectric semiconductor element is located between the low temperature side and the high temperature side, especially in the constricted part, by arranging a heat insulating and electrically insulating plate-like member that blocks the heat flow. In order to prevent this, it is possible to further reduce the efficiency and loss.

FIG. 1 shows the simplest configuration as Embodiment 1 of the present invention. (A) is an example in which an electrode is joined to a prismatic thermoelectric semiconductor element, (b) is an example in which an electrode is joined to a cylindrical thermoelectric semiconductor element, and (c) is a constricted shape at the central part of the prismatic thermoelectric semiconductor element. And (d) is an embodiment in which the central portion of the cylindrical thermoelectric semiconductor element is constricted. Reference numeral 1 denotes a P-type thermoelectric semiconductor element or N-type thermoelectric semiconductor element, and 2 denotes an electrode. When the electrode 2 is bonded to the thermoelectric semiconductor element 1, the electrodes are not simply bonded at the upper and lower ends of the thermoelectric semiconductor element, but are sandwiched or surrounded by the electrodes from the end surface to the side surface of the thermoelectric semiconductor element, thereby reducing the current density. The feature is that it is made larger. The electrode is preferably in the form of a dish having a recess for joining the thermoelectric semiconductor elements. This substantially increases the contact area between the thermoelectric semiconductor element and the electrode. Furthermore, the loss caused by the heat flow between the end faces is reduced by adopting a structure with a constriction in the center.

The material of the thermoelectric semiconductor element 1 is BiTePb (low temperature to 200 ° C.), iron silicide (300 to 700 ° C.), or the like. The electrode 2 is bonded or vapor-deposited with a material having high conductivity such as copper. It is desirable to use nickel plating together.

FIG. 2 shows, as Example 2, process schematic diagrams (A) to (D) and a cross section (E) for joining a thermoelectric semiconductor element so as to surround an electrode. In the embodiment, the thermoelectric semiconductor element is joined so as to surround the electrode. The thickness of the electrode 2 and the solder joint are drawn somewhat exaggerated. The above is a case where the module has a single thermoelectric semiconductor element. FIG. 2b shows an example of an electrode suitable for a π-type structure module. The left is for a prism and the right is for a cylinder. Both are made in a dish shape having a pair of (two) recesses in accordance with the thermoelectric module having a π structure to be joined.

FIG. 3 is a third embodiment showing a schematic diagram of an assembling process constituting the π structure module. Place a plurality of electrodes 2 on a jig that also serves as a hot plate (not shown), put solder paste 3 in the portion indicated by the wavy line in the figure, and (a) → (b) → (c) → (d) in this order. The electrode 2 and the thermoelectric semiconductor element 1 are joined. The electrode is the same as in FIG. 2b. In the figure, the solder 3 is indicated by a wavy line so as to fill the concave portion, but the amount is appropriate so that the solder does not overflow excessively. The solder electrode covers the thermoelectric semiconductor element so as to surround a part of the side surface to widen the contact area between the thermoelectric semiconductor element and the electrode.

Many π structures are aligned with the upper and lower sides sandwiched between the heat sink and the heat receiving plate 4. The heat radiating plate and the heat receiving plate are made of a heat conductive and electrically insulating material. For example, a sheet-like ceramic substrate can be used.

Depending on the pattern, the module may be a thermoelectric element composed of hundreds to thousands of pairs. When used as a power generation device, lead wires are drawn out from both ends to the electrode and connected to a battery (not shown) for storage or electrically connected to the device used.

FIG. 4 is Example 4 in which an N-type thermoelectric semiconductor element and a P-type thermoelectric semiconductor element are modules having a π structure, and FIG. 4A is an example in which a columnar thermoelectric semiconductor is a π structure. These are examples of a π structure in which a constriction 73 is added to the central portion of the thermoelectric semiconductor. For example, the electrode shown in FIG. 2b is used. The reason for providing the constriction in the thermoelectric semiconductor element is to reduce the loss due to the heat flow as described with reference to FIG. 1, but the examples of FIGS. 4C and 4D further reduce the loss due to the heat flow. In order to reduce, it is a longitudinal cross-sectional view of what attached the thermal-flow prevention sheet 5 to the module. In (c), a single sheet type heat-flow blocking sheet was provided at the center of the module. Moreover, in (d), the thermoelectric semiconductor which provided the constriction in the middle was equipped with the type | mold heat-through-flow interruption | blocking sheet | seat divided | segmented for every row | line | column. As the material for the sheet, organic urea and phenolic paper are optimal. A polyimide resin, an aramid resin, a fluorine resin, a sheet-like ceramic, or the like can be used as long as it has electrical insulation, heat insulation, and moisture resistance.

FIG. 5 shows an example of the heat-flow blocking sheet 5. (A) and (b) are single sheet type thermal-flow interruption | blocking sheets for thermal-flow interruption | blocking in a prismatic or cylindrical type thermoelectric semiconductor element. Further, (c) and (d) are split-type thermal flow-through blocking sheets for blocking thermal flow-through in prismatic and cylindrical thermoelectric semiconductor elements.

When the flow-through prevention sheet 5 is provided in a unit including a large number of thermoelectric semiconductor elements, the pattern-pressed paper (paper-like member) as shown in FIGS. 5A and 5B is slightly bent before joining the electrodes. Then I spread it between the elements in a fixed position. It is preferable to provide a binder that sandwiches the ear portion of the paper over the entire circumference of the unit, and to form the frame 6 on the outer periphery of the unit and give up.

FIG. 6 is a top view (cross-sectional view immediately below the electrode) of Example 6 in which the heat-flow blocking sheet 5 is mounted on a prismatic thermoelectric semiconductor element, and the heat release / heat absorption plate 4 is not shown. (A) is the Example which attached | subjected the single sheet | seat type heat-flow interruption | blocking sheet | seat to the module, (b) is the Example which attached | subjected the division | segmentation type heat-flow interruption | blocking sheet | seat to the module.

As long as the heat-flow blocking sheet 5 is a flexible and stretchable material, it can be formed of a single sheet. However, not only a flexible material but also a hard material may be used for the heat-flow blocking sheet. In that case, if the sheet | seat divided | segmented separately for every row | line | column is applied, a heat insulation effect can be exhibited more advantageously. Before or after attaching the heat radiating (endothermic) plate 4, the heat-flow blocking sheet 5 can be attached. The heat-flow blocking sheet 5 can be fixed by providing an outer frame 6.

In Example 7 shown in FIGS. 7A, 7B, 7C, 7D, and 7E, when the electrode is bonded to the thermoelectric semiconductor element, the surface of the portion of the thermoelectric semiconductor element that is in contact with the electrode is an uneven surface. The current density is increased by making the contact area between the thermoelectric semiconductor element and the electrode substantially non-planar. That is, the shape of the joint portion of the thermoelectric semiconductor element is not only uneven as shown in FIGS. 7B, 7C, 7D, 7E, but also comb-shaped, corrugated, or perforated as shown in FIG. 7D. The electrodes are joined in conformity with these non-planar surfaces. In the embodiments of FIGS. 7B to 7E, a plurality of them can be arbitrarily combined. Moreover, you may combine with the heat-flow interruption | blocking sheet | seat 5 of FIG. 5 (FIG. 6).

FIG. 8 shows an example 8 in which a constriction structure 73, a slit 71, and the like are provided at the center of the thermoelectric element 1. FIG. The constriction structure can have various shapes such as FIGS. Further, in order to efficiently extract electric power from the thermoelectric module, the slit 71 is formed at an arbitrary location of the thermoelectric semiconductor element as shown in FIG. 8C in order to optimize the resistance value of the thermoelectric semiconductor element in the thermoelectric unit. Alternatively, the dot hole 72 can be provided to adjust the resistance value to a desired value.

In the thermoelectric module, a structure surrounded by electrodes to the side surface is applied, and in order to insulate the low temperature side and the high temperature side of each thermoelectric semiconductor element, a constricted structure 73 is formed between both the high temperature and low temperature sides like a bobbin. . Since there is a space in the center, the heat flow can be reduced.

The high-efficiency low-loss thermoelectric module of the present invention can be applied as an efficient Peltier effect cooling device. Even if the Z value of the thermoelectric semiconductor element is the current capacity, the power generation capacity by the Seebeck effect per unit area or the cooling capacity by the Peltier effect is improved.

The high-efficiency low-loss thermoelectric module of the present invention is applied as described in Patent Document 1 (particularly, FIGS. 10 to 12 of the same document) and added to a power generation system using waste heat. It can be used for easy thermoelectric generation.

(Embodiment 1) Simple embodiment of the present invention (a) is an example in which an electrode is joined so as to cover a prismatic thermoelectric semiconductor element to the side surface. (B) is an electrode so that a cylindrical thermoelectric semiconductor element is covered to the side surface. Example of joining (c) An example in which the central part of a prismatic thermoelectric semiconductor element is constricted. (D) An example in which the central part of a cylindrical thermoelectric semiconductor element is constricted. (Example 2) Process schematic diagrams (a) to (d) and a cross-sectional view (e) for joining so as to cover the thermoelectric semiconductor element with electrodes. Electrode for applying the present invention to a π-type structure module (for prisms and cylinders) (Embodiment 3) Schematic diagram of assembly process for forming a π-type structure module (i) to (d) (Example 4) Example in which N-type thermoelectric semiconductor element and P-type thermoelectric semiconductor element are modules of π structure (a) Example in which columnar thermoelectric semiconductor is formed in π structure (b) In central part of thermoelectric semiconductor Example of π structure with constriction (c) Example in which one type of heat-flow blocking sheet is mounted on module (a) (d) Split type heat-flow blocking sheet in module (b) Wearing example (Example 5) Examples of thermal flow-through blocking sheet (a) Single sheet type thermal flow-through blocking sheet for prismatic thermoelectric semiconductor element (b) Single-sheet type thermal flow-through blocking sheet for cylindrical thermoelectric semiconductor element (c) Rectangular column Split type thermal flow breaker sheet for thermoelectric semiconductor element (d) Split type thermal flow breaker sheet for cylindrical thermoelectric semiconductor element (Example 6) Top view of mounting a heat-flow blocking sheet on a prismatic thermoelectric semiconductor element (a) Example of mounting a single sheet type heat-flow blocking sheet on a module (b) Module with a split-type heat flow blocking sheet Example attached to (Example 7) Various examples in which the junction surface between the thermoelectric semiconductor element and the electrode is substantially enlarged (a) A longitudinal sectional view of a basic example in which the junction surface of the thermoelectric semiconductor element is surrounded by the electrode (b) ) An example in which the junction surface between the thermoelectric semiconductor element and the electrode is made into a fine waveform (c) An example in which the junction surface is made into a rough waveform (d) An example in which a dot hole is provided in the vicinity of the junction surface (e) The junction Example of comb-shaped surface (Example 8) Vertical sectional view of an example in which the side surface of the thermoelectric semiconductor element has various structures (a) Example in which the center part of the side surface of the thermoelectric semiconductor element has a constriction structure 73 (b) (a) with a constriction structure Another example (c) Example provided with slits or dot holes Explanatory drawing of existing basic π structure (a) Principle diagram of power generation by the Seebeck effect of π structure (b) Principle diagram of heating (heat radiation) / cooling (heat absorption) device by Peltier effect of π structure Explanatory drawing of electron transfer in existing thermoelectric device (N-type thermoelectric semiconductor element)

Explanation of symbols

1 P-type thermoelectric semiconductor element or N-type thermoelectric semiconductor element 2 Electrode 3 Solder (solder paste)
4 Heat transfer plate (heat radiating plate or heat absorbing plate)
5 Heat-flow blocking sheet 6 Outer frame 71 Slit 72 Perforated (dot hole) structure 73 Necked structure

Claims (3)

In a thermoelectric semiconductor module having one or a plurality of units formed of thermoelectric semiconductor elements and electrodes bonded to the low temperature side and the high temperature side at both ends, the electrodes sandwich the thermoelectric semiconductor elements from the end surface to the side surface of the thermoelectric semiconductor element. A high-efficiency, low-loss thermoelectric semiconductor module characterized in that the area where the thermoelectric semiconductor element and the electrode are in contact with each other is substantially increased.
The cross-sectional areas of the low-temperature side and the high-temperature side of both ends of the thermoelectric semiconductor element are larger, and the intermediate cross-sectional area between the low-temperature side and the high-temperature side of the thermoelectric semiconductor element is smaller, so that a pinned neck structure is formed as a whole. The high-efficiency low-loss thermoelectric semiconductor module according to claim 1
3. A heat insulating and electrically insulating plate-like member is disposed in an intermediate portion between the low temperature side and the high temperature side of the thermoelectric semiconductor element to block the heat flow around the module. High efficiency low loss thermoelectric module

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