DE6605931U - THERMOELECTRIC GENERATOR - Google Patents

Description

«.Π. vj II Ji. I - J. /. (J /

Heat

.54 / 67 Sta-wy

Aktiengesellschaft Brown, Boveri * Cie., Baden (Switzerland)

Thermoelectric generator

The invention relates to a thermoelectric generator with thermoelectric elements, each with two cylindric views, paräV IeI arranged semiconducting thermocouple legs, whose plane-parallel band surfaces at the cold leg ends each with soldered to a power shoe and over the bite ends of the legs Pressure contacts and an electrically conductive bridge with each other are connected.

By using appropriately doped semiconductors as thermocouple legs, thermoelectric generators have in solving specific power supply problems has for the first time gained greater importance in recent years. From the special

- 2 - 34/67

Material properties of the semiconductors used for this result sieve, but special, partly contradicting one another Requirements for construction. In general, these semiconductors have a strongly non-linear thermal expansion that makes it difficult to contact them. Further problems arise from the usually high oxidizing capacity of these semiconductors and by mass transport, which occurs with temperature gradients occurs due to the non-existent atmosphere.

In some known thermoelectric generators, such as those according to the French. In patent specification 1,389,896 _Ä , a consistently good contact is established between the hot ends of the thermocouple legs of a thermocouple and the bridge that connects these hot ends with one another with the help of pressure contacts, the necessary for this

Housing is housed. This solution is relatively expensive, and also has the disadvantage that when. a relatively large number of elements in one generator Space is claimed.

The aim of the invention is a thermoelectric generator, which does not have these specialist parts and which, thanks to a particularly simple and inexpensive construction, provides a secure end to the

860593134 7.70

34/67

Thermocouple legs guaranteed against the coding atmosphere and also, in connection with a suitable thermal insulation, the semiconductor mass transport largely prevented.

The thermoelectric generator according to the invention is characterized in that a thermally and electrically insulating tube is pushed onto each thermocouple leg, which in turn is encased by a metallic protective tube with a side with the bridge, in particular by soldering , is connected in a gas-tight manner, -which there is a gap between each other end vail learning current shoe, which is thermally and electrically insulating by a plastically deformable

: Abdiehisaß is filled out.

The invention is explained by an example of the iriguren example

1 shows an element used to build the thermoelectric generator in section. Two cylindrical, parallel thermocouple legs 1 and 2 made of ρ or η conductive lead telluride are hard-soldered at their cold ends 3 depending on the age of contact plates 4, which in turn are also brazed with axles Silver-plated power shoes 5 are connected to the yerbinching of the hot ends. 6 & gv thermocouple leg serves a

- 4 - 34/67

Bridge 7t consisting of a cover plate 8, a centering plate 9 and two contact pieces 10. In making the Bridge 7, the contact pieces 10 next to the plates 8 ^ and 9 soldered and the contact surfaces ground flat together. The protective tubes U are finally soldered to the bridge 7. The plates 8 and 9 ″ and the protective tubes 11 exist made of a corrosion-resistant steel. Bisen or a chroafraie type of steel is used to manufacture the TO contact pieces. This way it is avoided that by superficial Formation of chromium oxide reduces the quality of the electrical contact.

In this context, it can be regarded as a general rule that SS solCuv 5j »t BTi 51 1.8« fujf di? BautslEtsitucke IC used may. whose oxides are reduced at the operating temperature of the semiconductor material of the thermocouple legs »

For electrical and thermal insulation of the Ihereoeleaentschenkel Bind between them and the Schutsrohren U Isolier = tubes 12 inserted, which also serve as spacer sleeves. The length of these insulating tubes 12 is dimensioned so that after the introduction of the thermocouple legs between the ends of the Schutztfohre 11 and the contact shoes

- 5 - 34/67

a Dehungsfuge a width of Q, 5 1 bid remains free on. This expansion joint is filled with old silicone rubber 13 to form a gas-tight, flexible closure. The play between Therttoeleaentechenkeln 1 or 2 and the insulating tube 12 or between these and the protective tube 11 is as small as possible and boU only the free thermal expansion of this part * im

Ensure operation.

Pig. 2 geigt a thermoelectric generator in which several thermocouples 14 are arranged between two pressure plates 15 and 16, which help "? & tr bolt 1? and the compression springs 18, the thermocouples 14 under a uniform. Maintain the axial compressive stress. 15 with a ^ r suitable heat source and 41e pressure plate I ^ over iiihlrippeijt '

· ■ * '· ■ -' ■ ■ '...- >'>'■ , · "» 19 in connection with a KJihlmittoi. ^! :

■ "■. ■ ■. · '·>*' The mode of operation of the described Änordniuag.J.et'ntm is as follows.

To enfewhrnen Vm from the generator at thermoelektriechen aEgasessenea We * ciency electric current mim "sririschen the helssen and cold bottom of the thermocouple legs to maintain an appropriate temperature difference * SS in the use of lead telluride as the semiconductor material

- 6 - 34 / ^ 7

is between 300 ° - 5GO ⁰ G. The hot ends of the thermocouple legs have temperatures of 400 ° - 700 ° C and the cold ends, depending on the type of cooling, 150 ° - 200 ° C. For example, water cooling can easily reach a temperature of 150 °, while air cooling hardly ever drops below 20O ⁰ G the thermocouple legs (1,2) without the occurrence of significant thermal stresses and a good transfer of the contact pressure to the contact pieces (10). The contact pressure is selected to be sufficiently high that, at the operating temperature, surface pitting of the semiconductor material occurs at the hot leg ends, and excellent electrical contact is achieved as a result. In addition, the silicone rubber provides good thermal insulation between the cold and hot areas of the elements, thereby avoiding unnecessary heat losses. As a result of the special construction, the volume of gas associated with the semiconductor material is also kept very small, so that practically no mass transport of the semiconductor material occurs.

Claims (1)

! ■ EÄ.371321 * -5-7.67 - 7 - 34/67 D pfn sayings 1. Thermoelectric generator with thermoelectric elements each with two cylindrical semiconducting thermocouple legs arranged in parallel, their plane-parallel end faces at the cold leg ends each soldered to a power shoe and attached the hot leg ends via pressure contact and one electrically conductive bridge are interconnected, characterized ^ that on each thermocouple leg (1,2) a thermally and electrically insulating tube (12) is pushed, which in turn is encased by a metallic protective tube (11), which with one end to the bridge (7), in particular through Soldering, is connected gas-tight, with a gap between its other end and the current shoe (5), which is through a plastically deformable, thermally and electrically insulating sealing compound (13) has precipitated. 2. Thermal electric generator according to claim 1, characterized in that that the contact pressure of the pressure contacts is large enough to allow the semiconductor material to flow over the surface to ensure at the hot leg ends (6). - 8 - 34/6? D. 3 ο Shersoeiektrischer Generator gosass A ^ gprseh 1 * characterized in that the contact pieces (10) of the pressure contact · consist of a metal whose oxide is at operating temperature is reduced by the semiconductor material. 4. Thermoelectric generator according to claim 3, characterized characterized in that the contact pieces (10) of the pressure contacts made of steel without chrome yellow, and the Sheraoelenintschenkel (1,2) made of lead uride. 5. Thermoelectric generator according to claim 1, characterized! that silicone rubber (1?) is used as a sealing compound is. Corporation BROWH, BOVERI & CI3.