JPH0337246Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermoelectric device, and particularly to the structure of a heat exchange board thereof.

[Prior art and its problems] A P-type semiconductor and an N-type semiconductor are bonded via metal to form a PN element pair, and one of the bonded portions generates heat depending on the direction of current flowing through this bonded portion. Thermoelectric cooling elements that utilize the so-called Peltier effect, in which one joint is heated at the same time as the other joint is cooled, and thermoelectric power generating elements that utilize the so-called Seebeck effect, in which one joint is heated and the heat is dissipated from the other joint, are small. Due to its simple structure, it is widely used in various devices such as portable coolers and local power sources.

A thermoelectric device formed by collecting a large number of such thermoelectric elements is, for example, as shown in FIG. 112 to have good thermal contact with it.
A pair of PN elements 113 are sandwiched between each other, and each element pair 113 is connected in series by first and second electrodes 114 and 115 made of copper plates or the like.

By the way, these first and second electrodes are usually made of copper plates as shown in FIG. 4 so that they can withstand large currents, and heat exchange substrates 111 and 112 are made of insulating substrates with good heat dissipation such as alumina ceramic substrates.
Metallized layer pattern 116 formed on the surface
(Two-layer structure consisting of a metallized layer and a plating layer) is fixed onto the solder layer 117 via a solder layer 117.

Two P-type thermoelectric elements or two N-type thermoelectric elements are alternately fixed onto the first and second electrodes via solder layers 118 to form a PN element pair 113 and each element pair. are connected in series.

If such a structure is subjected to severe temperature changes during the soldering process during assembly or during use, the difference in thermal expansion coefficients between copper and alumina ceramic will cause the board to warp (due to thermal strain). . As a result, the soldered parts, the thermoelectric elements, or the board itself are subjected to stress, which may cause damage and reduce reliability.

Therefore, a method has been proposed in which a copper plate is bonded to the back side of the alumina ceramic substrate in the same way as the front side.

However, when copper plates are bonded with the same pattern on the front and back in this manner, the exposed portions of the alumina ceramic between the patterns have the disadvantage that they are mechanically brittle and easily break.

This invention was made in view of the above-mentioned circumstances,
The purpose of the present invention is to increase the mechanical strength of a heat exchange board and provide a highly reliable thermoelectric device.

[Means for Solving the Problems] Therefore, in the present invention, the electrode patterns formed on the front surface side of the heat exchange substrate of the thermoelectric device are arranged so that the grooves between the electrode patterns, that is, the portions without patterns do not coincide with each other. A pattern made of conductors is also placed on the back side.

[Function] According to the heat exchange board having such a structure, stress is applied to the same degree from both sides and is canceled out, so that warping does not occur, and the grooves between the patterns on both sides are configured so that they do not match. This eliminates the occurrence of cracks in the grooves, increases mechanical strength, and improves reliability.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a view showing the appearance of a thermoelectric device according to an embodiment of the present invention, and FIGS. 2a and 2b are views showing a heat exchange board of the same device.

In this thermoelectric device, a plurality of low-temperature side bonding electrode patterns 1 and a plurality of high-temperature side bonding electrode patterns 2 are formed on opposing surfaces, and similar first and second back patterns are formed on the back surface, respectively. 10
17 P-type thermoelectric elements 5 and 17 N-type thermoelectric elements 6 are arranged alternately by first and second heat exchange substrates 3 and 4 made of alumina ceramic substrates on which 0.0,200 is formed. By sandwiching and fixing via the solder layer 7, the adjacent P-type thermoelectric element and N-type thermoelectric element are connected by the low-temperature side bonding electrode pattern and the high-temperature side bonding electrode pattern to form a PN element pair. 8 and this PN
The element pair 8 is configured to be connected in series with each other, and the first electrode lead 9 and the second electrode lead are connected to the high temperature side bonding electrode patterns located at both ends of the circuit.
Electrode leads 10 are disposed, and electricity is supplied thereby, so that the first heat exchange board side becomes a low temperature part and the second heat exchange board side becomes a high temperature part.

Here, the first and second heat exchange substrates are
Although they have the same structure, for example, the first heat exchange substrate is made of an alumina ceramic substrate as shown in FIGS. A low-temperature side bonding electrode pattern 1 consisting of a large number of copper plates 1d fixed in an aligned manner via a solder layer 1c is disposed on a metallized pattern consisting of a fired layer) 1a and a nickel plating layer 1b. Similarly, on the back side, the grooves m between the patterns, that is, the exposed parts of the alumina ceramic substrate are arranged so that they do not match on the front and back sides,
Metallized layer 100a and nickel plating layer 100
A metallized pattern consisting of b and a solder layer 100
A first back pattern 100 consisting of a copper plate 100d and a large number of copper plates 100d is disposed.

In this thermoelectric device, each of the first and second heat exchange substrates has a pattern made of the same material as the electrode pattern on the front side not only on the front side but also on the back side. When subjected to stress, these are canceled out and no warping occurs. In addition, since the patterns on both sides are staggered so that the grooves do not coincide with each other, cracks do not occur in the grooves, and the pattern on the back side also acts as a reinforcing material, increasing mechanical strength. Improved reliability.

In the examples, the low-temperature side bonding electrode pattern, the high-temperature side bonding electrode pattern, and the back surface pattern are formed on a metallized pattern consisting of a metalized layer and a plating layer formed on an alumina ceramic substrate through a solder layer. Although it is constructed by fixing copper plates, the structure can be appropriately selected as necessary, such as by patterning the copper layer on the DBC substrate using a photolithography method.

[Effect] As explained above, according to the present invention, a pattern made of the same material as the electrode pattern on the front side is also formed on the back side of the heat exchange board, but the positions are shifted so that the grooves do not match. Therefore, even in the face of rapid temperature changes, the heat exchange substrate does not warp or crack, making it possible to provide a highly reliable thermoelectric device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a thermoelectric device according to an embodiment of the present invention;
FIGS. 2a and 2b are a plan view and a side view, respectively, of a heat exchange board of the same device, FIG. 3 is a conventional thermoelectric device, and FIG. 4 is a partially enlarged view of the heat exchange board of the same device. 111...first heat exchange board, 112...second
heat exchange board, 113...PN element pair, 114...
...First electrode, 115... Second electrode, 116...
...Metallization layer pattern, 117...Solder layer, 1
18... Solder layer, 1... Electrode pattern for low temperature side bonding, 2... Electrode pattern for high temperature side bonding, 100...
...First back pattern, 200... Second back pattern, 3... First heat exchange board, 4... Second heat exchange board, 5... P type thermoelectric element, 6... N type thermoelectric element Element, 7...Solder layer, 8 ...PN element pair, 9...
...First electrode lead, 10... Second electrode lead, 1a, 100a... Metallized layer, 1b, 1
00b...Nickelmetsuki layer, 1c, 100c...
...Solder layer, 1d, 100d...Copper plate, m...Groove portion.

Claims (1)

[Claims for Utility Model Registration] (1) A thermoelectric device comprising an element portion consisting of at least one thermoelectric element pair connected via an electrode pattern disposed on the surface of a heat exchange substrate, A thermoelectric device characterized in that the heat exchange substrate is provided with a back pattern on the back side that is substantially the same as the electrode pattern and is arranged in a shifted arrangement so that the grooves do not match. (2) The electrode pattern and the back pattern are comprised of a plurality of copper plates fixed in an aligned manner via a metallized layer formed on a heat exchange substrate. Thermoelectric device described in item 1). (3) The heat exchange board is made of a DBC board, and the electrode pattern and back pattern are
2. The thermoelectric device according to claim (1), wherein the thermoelectric device is a copper pattern formed by patterning a copper layer on the surface of a DBC substrate.