The reliability of thermoelectric modules (TEM) is consistently prioritized. TEMs have no moving parts, which contributes to their high reliability.
THE MAIN PROBLEMATIC ELEMENTS OF A TEM'S DESIGN ARE:
Electrical contacts of the thermocouple legs
Thermal contacts of the heat spreaders
DESTRUCTIVE FACTORS FOR TEMs INCLUDE:
Improper operation
Thermal diffusion
Thermal cycling
A significant number of TEM failures are associated with violations of installation and operating rules. We have developed an installation guide and operating recommendations for TEMs. Familiarizing oneself with this document is mandatory for every TEM user.
During long-term operation, TEMs experience an increase in electrical resistance and a decrease in efficiency. The main cause of this process is thermal diffusion of the interconnecting conductor material into the the thermocouple leg material. As a result, an intermediate layer forms at the contact point over time, which has low strength for semiconductor materials based on Bi2Te3. Research has shown that microcracks form in this layer, leading to an increase in the electrical resistance of the contact.
To ensure the reliability of the thermocouple contacts, a method of electrochemical deposition of a multi-component anti-diffusion layer is used. Experimentally selected layer parameters, application, and processing modes ensure the high reliability of the thermocouple contacts.
THERMAL CYCLING
The second destructive factor is thermal cycling. Temperature changes in the contact zone of materials with different coefficients of linear expansion lead to mechanical stresses. These stresses cause cracks and delaminations in the thermal and electrical contacts of TEMs.
TEM RESISTANCE TO THERMAL CYCLING IS ENSURED BY:
Optimal selection of materials
Application of measures to increase adhesion
A special accelerated testing methodology for modules' reliability and specialized equipment, developed and manufactured by our specialists, allow for continuous monitoring of this important parameter. The modules we produce undergo periodic testing for resistance to mechanical factors: shocks, linear acceleration, and vibration.
Mechanical shocks of up to 2000 cycles with a maximum acceleration of up to 15g and a shock pulse duration of 2-4ms in three directions. Linear acceleration up to 20g for up to 4ms in three directions. Sinusoidal vibration at a frequency of up to 55 Hz and an acceleration amplitude of 2g in three directions for 30 minutes.
The probability of TEM's failure-free operation is not less than 0.98 with a confidence probability of 0.8. The mean time between failures (MTBF) for our modules is not less than 200,000 hours.
