RU2575614C2 - Thermoelectric generator with high gradient of temperatures between soldered joints - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: all branches of p-type are located in a single plane, and all branches of n-type - in another parallel plane. Semiconductor branches are made in the form of thin films of different thickness for p- and n-type. Metal soldered joints for contact with semiconductor branches are selected so that in the metal the electrons have lower energy than in the semiconductor. And on the second soldered joint the metal is selected with the energy of electrons, which is higher than in the semiconductor, therefore the result will be similar. Also heat exchange surfaces are used inside the thermoelectric device.

EFFECT: increased efficiency due to reduction of conductive stray losses between hot and cold soldered joints, reduction of stray joule heat emissions and use of contact phenomena between metal soldered joints and semiconductor branches.

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Description

The invention relates to the field of thermoelectricity and can be used in thermoelectric generators.

Known thermoelectric module containing semiconductor branches of p- and n-conductivity, connected by switching buses with the formation of an electrical circuit [1].

To increase the efficiency of the thermoelectric generator and reduce the level of conductive heat transfer, it is advisable to spatially place p- and n-branches in different planes, making it difficult to conduct heat transfer between them, reduce the electrical resistance of semiconductor branches by reducing their thickness, select materials for metal junctions for the semiconductor-metal boundary individually for incoming and outgoing currents, as well as to supplement the system of heat removal to the environment with new heat exchange surfaces .

The purpose of the invention is the creation of a highly efficient thermoelectric generator with a high temperature gradient.

This is achieved by the fact that p- and n-type semiconductor branches, in order to reduce Joule losses, are made in the form of thin films with minimal resistance to the flowing current. The smaller the film thickness with respect to its cross section, the less is the resistance to the flowing current. For p- and n-type branches, the film thickness will be individual and will depend on the thermophysical properties of the material. In existing thermoelectric generators, the height of p- and n-type semiconductor branches is the same [2]. This limitation is imposed by design and technological requirements in production. However, p- and n-type semiconductor branches have different resistance to electric current, voltage drop, thermal conductivity and other parameters, which limits the optimization of the operating conditions of the thermoelectric generator as a whole. The placement of semiconductor branches of p- and n-type at different levels allows you to independently change the height of the branches of p- and n-type. This allows you to achieve the same voltage drops and currents in semiconductor branches of various types.

In existing thermoelectric generators, hot and cold junctions are made of one metal [2]. However, between the junction and the semiconductor when current flows, thermoelectric phenomena occur with the release or absorption of heat. Depending on the electron energy in the metal and p-type and n-type semiconductors, as well as the direction of electron motion, the mode of converting the temperature difference into current changes. Electrons in various metals can have more or less energy compared to the energy of electrons in p- and n-type semiconductors [3].

It is advisable to select metal junctions for contact with the semiconductor in such a way that, at a temperature difference between the metal and the semiconductor, the maximum current from the Seebeck effect is obtained due to the fact that the electrons in the metal have lower energy than in the semiconductor. And at the second joint, a metal with an electron energy greater than that in the semiconductor is selected, so the result will be similar. Thus, a rational choice of materials for metal junctions, taking into account the contact phenomena between the metal and the semiconductor, allows us to obtain a large current value (Seebeck effect) in both cases. The greater the difference in electron energies in metal junctions, the greater the effect on both junctions and the less stray conductive heat transfer.

Since metal junctions are in contact with p- and n-type semiconductor branches, it is impossible to simultaneously provide optimal conditions for the thermal effect for both types of branches. But this is not necessary when using the design of a thermoelectric generator with topologically separate placement in space at different levels of p- and n-type branches. It is enough to arrange p-type semiconductor branches at a considerable distance from the objects of cooling and heating (by reducing spurious conductive heat transfer back to the cooling object) and to ensure heat removal not only from one external surface of the p-type branches, but also from the opposite inner side of these p- branches type. It is also possible to carry out heat removal from the inside of the cooling n-type semiconductor branches and from the connecting metal conductors, which can be made in the form of flat plates. In this case, in comparison with traditional schemes of thermoelectric generators, the surface of heat removal increases at least three times. In addition to one external surface of p-type branches, internal surfaces of p- and n-type branches are added, as well as the effective surface of the connecting metal conductors.

In FIG. 1 shows the structure of a thermoelectric generator with a high temperature gradient.

The structure of the thermoelectric generator is a thin-film semiconductor branch of p-type (2, 4, 6, 8, 10, 12, 14, 16, 18) and n-type (1, 3, 5, 7, 9, 11, 13, 15 17) located in different planes so that when a temperature difference is applied to the hot and cold junctions, current generation will begin, and in addition to the main current generation circuit between p- and n-type semiconductors, an additional effect will be obtained when current is generated at the contact p- and n-type semiconductors and junctions consisting of dissimilar metals, and the electron energy in meta Allah should be more or less, depending on the type of semiconductor (p and n) and on the direction of electron motion (from metal to semiconductor or vice versa). Heat is supplied to the semiconductor thermoelectric generator from the side of the upper junction (Q ₁ - input heat). Heat removal can be intensified by fan blowing of the lower junctions and air blowing of the internal junctions and conductors (Q ₂ is the heat removed). The connecting conductors between p- and n-type semiconductors must freely pass current and be of such a length that the conductive heat transfer between the hot and cold junctions of the thermoelectric generator practically ceases. If necessary, they can be made in the form of flexible electrically insulated metal conductors in order to arbitrarily change the distance and location in space of heat-generating and heat-absorbing surfaces.

Using the presented device will allow you to create more efficient thermoelectric generators by reducing the conductive spurious losses between hot and cold junctions, reducing spurious joule heat and using contact phenomena between metal junctions and semiconductor branches.

Literature

1. Thermoelectric module: US Pat. 2425298 Ros. Federation: IPC F25B 21/02, H01L 35/32 / Sidorenko N.A., Grishin V.I. - Declared. 03/22/2010, publ. 07/27/2011.

2. Ismailov T.A. Thermoelectric semiconductor devices and heat transfer intensifiers. - St. Petersburg: Polytechnic, 2005.

3. Anatychuk L.I. Thermoelectricity T2. - Kiev: Bukrek, 2003 .-- 386 p.

Claims (1)

A thermoelectric generator with a high temperature gradient between junctions made of p- and n-type semiconductor branches in such a way that all p-type branches are located in one plane, and all n-type branches are in another parallel plane, characterized in that the semiconductor the branches are made in the form of thin films of various thicknesses for p- and n-type, as well as the use of various materials of metal junctions for incoming and outgoing current between junctions and semiconductor branches and the use of an additional heat sink from Cored oil surfaces of the thermoelectric device.

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