Thermoelectric modules from Laird now provide one million temperature cycles
Laird has improved its Power Cycle (PC) series thermoelectric modules (TEMs). They have been tested to more than one million temperature cycles, offering a significantly longer operating life and lower overall cost of ownership compared to standard TEMs, says the company.
The Power Cycling thermoelectric module is designed for applications that require high reliability and high volume thermal cycling between multiple temperature set points. The enhanced PC series is now proven to perform more than one million temperature cycles, extending the mean time between failure (MTBF) in molecular diagnostics, clinical diagnostics and analytical instrumentation, says Laird.
Thermal cycling exposes TEMs to mechanical stresses, due to the module contracting and expanding from repeated cooling and heating cycles. Standard TEMs are traditionally designed for refrigeration applications only. The high-temperature diffusion of impurities and mechanical stresses over time can significantly reduce the operational life of a standard TEM.
The Power Cycling thermoelectric modules are constructed to reduce the amount of stress induced on the thermoelectric elements during operation. This enables the high number of temperature cycles. Combined with an operating temperature up to 120 degree C, the PC series exceeds the requirements for high volume power cycling applications. Laird also says that the thermoelectric modules provide a lower total cost of ownership, while increasing throughput of diagnostic equipment.
The new PC Series TEM is constructed with multiple layers between the ceramic substrates, copper bus bars and semiconductor couples. To reduce thermally induced stress, a flexible and thermally conductive soft layer is inserted between the cold side ceramic substrate and copper bus bars. The integration of the polymer into the thermoelectric modules absorbs the mechanically induced stresses caused by rapid temperature cycling. As a result, the stress induced on the semiconductor couples and solder joints are significantly reduced, extending the overall operational life of TEM.