A thermoelectric module (thermo-module) consists of P and N semiconductor elements and ceramic substrates. In appearance, it is a unit in which pairs of elements are sandwiched between ceramic substrates, and the elements are electrically series-connected, P-N, P-N. Its size is generally 10-40 mm square and 3-6 mm thick. Heat is absorbed from one side of the module and pumped to the other side while applying direct current, so that the temperature is precisely controlled.
Demand for thermo-modules is growing significantly - one factor is the growth of fiber-optic networks accompanied by development of IT utilization.
Laser diodes for fiber-optic networks need temperature control so that the light wavelength stays constant in order to make a stable signal transduction. The light wavelength strongly correlates to the diode temperature. That's why thermo-modules are needed.
KELK leads an industry of small and precise thermo-modules for this purpose.
Basic principal of "Heat to electricity" "Electricity to heat"
1. Peltier effect
The Peltier effect is a creation of temperature difference from electric current. When direct current is passed across the different materials (metal or semiconductor) that are connected at two junctions, one junction absorbs heat and the other diffuses it. If the current direction is reversed, hot and cold junction is reversed.
Our thermo-modules are based on this effect.
2. Seebeck effect
The Seebeck effect is transduction of temperature difference to electricity. It is the reverse of the Peltier effect. When applying a temperature difference between two junctions, it produces electricity.
This effect can be used for electric generation, but there are fewer applications than peltier effect as the efficiency is still not enough.
1. High performance material
Generally, element material of thermo-modules is made by a crystalline growth method. KELK has developed a hot-forged method and is the first in the world to have commercially produced thermo-modules using this method.
The advantages of hot forged material are:
(2)higher mechanical strength
(3)uniformity of the performance and strength.
Higher performance provides higher temperature delta, larger heat pump or lower power consumption of the thermo-module. We continue our efforts in material R&D towards much higher performance.
2. Robotic assembly
KELK assembles thermo-modules using automatic robots. These place pairs of elements with precise positioning, so that the quality of the thermo-module is consistent.
Robotic assembly affords not only consistent mass-volume quality, but also excellent cost-performance and flexibility for new designs.
3. Total inspection
Our thermo-modules undergo 100% inspection and screening after assembly, so that high reliability is guaranteed.