Principle of cooling plate

Schematic diagram of refrigeration slice

Schematic explanation

● In 1834, French Partier discovered that when the current flows through the contact point formed by two different conductors, the electronic energy level will jump, which is called the Partier effect. The Peltier effect is the theoretical prototype of semiconductor refrigeration chips.

● When electrons flow from low-energy P-type materials to high-energy N-type materials, they will jump from low-energy level to high-energy level, which means that electrons need to absorb heat, thus forming a cold surface at this node (the cold surface of the cooling fin);

● On the contrary, when electrons flow from high-energy N-type materials to low-energy P-type materials, they will jump from the high-energy level to the low-energy level, which means that the electrons need to release heat, thus forming a hot surface (the hot surface of the refrigeration chip) at this node;

● In fact, most closed loops formed by different metals have this phenomenon; At present, commercial bismuth telluride based thermoelectric materials have more obvious Peltier effect, that is, the electronic energy level jumps higher, and the corresponding cooling efficiency is higher. At present, in the world, the generally commercialized semiconductor refrigeration chips are mainly bismuth telluride based (taking bismuth telluride as the base material, and making different doping to form P and N grades);

● As shown in the schematic diagram, the cooling plate is a circuit composed of PN thermoelectric materials (generally a series circuit).

● The semiconductor refrigeration chip is a device without moving parts, but because the thermal expansion coefficient of the materials used is different, the device will generate internal stress when the temperature changes; Especially when the temperature change rate (such as cold and hot cycle) is large, the internal stress will be large, so it is necessary to select high reliability devices.