| Since the beginning of the new century,our country has been increasing input in space exploration field gradually.China has carried out 921 manned space flight,lunar exploration,mapping,meteorology,reconnaissance,earth observation and communications satellites,spacecraft and target aircraft and other key national special research in national level.To carry out special research based on high precision,high reliability of space using star sensor,calibration blackbody,CCD devices,infrared focal plane,ultraviolet sensor,loop heat pipe,research on the key technology of space laser.The common point of all these key technologies is the temperature control problem.Therefore,Selecting a suitable temperature controlling method is a key problem to ensure the success of space exploration projects.The thermoelectric cooling module(TEC)has been widely in the space temperature controlling field in recent years because its unique advantage.Considering the characteristics of without maintainability in space applications,the TEC system should have the the same lifetime as satellite,spacecraft and target spacecraft.At present the in orbit lifetime of low earth orbit spacecrafts is about 5 to 8 years,while that of high earth orbit is equal or more than 15 years.This paper is aimed on the design,manufacturing technology research and reliability verification of highly reliable TEC products applied in spacecrafts on orbit flight.In this work,we established the transition layer by introducing chemical nickel-plating technology,improving the soldering performance and blocking of heavy metal ions;improvement of soldering process,improve the TEC soldering uniformity and firmness;optimization of aging screening system,removing the early failure TEC;put forward the concept of vacuum deposition,the TEC is deposited on the surface of film,effectively prevent the high humidity,salt fog,acid erosion and other harmful gases;finally,we carried out the space environment adaptability and life test,the results can satisfy the requirement of more than 15 years lifetime in orbit and reliablility.Innovation of this paper lies in:(1)overcoming the chemical nickel-plating technology on thermoelectric material surface,improved the thermoelectric materials of infiltration and a strong degree of soldering;(2)adopting down drawing module for the first time,avoid the damage of the thermoelectric element,achieve no stress drawing module;(3)in the first use of "electrical aging and temperature cycling" ageing and screening method,solve the early failure of TEC;(4)by ultrasonic cleaning process improving cleanliness on TEC,introducing into the vacuum deposition process effectively prevent external moisture for TEC.In this paper,on the theoretical foundation and experimental research based,completed the space with high reliable thermoelectric refrigerator product design,key technological research and reliability verification.Provided in the paper of the design,process,reliability method will for future space with other TEC,expand the application lay theoretical basis,provide support on research ideas and methods. |
