A multi-stage thermoelectric refrigeration device life evaluation system and method
By evaluating the lifespan of multi-stage thermoelectric refrigeration devices through accelerated life testing and degradation models, the problem of difficult lifespan assessment in existing technologies is solved, enabling rapid and accurate lifespan prediction. This method is applicable to various environments and reduces resource consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 709TH RESEARCH INSTITUTE CHINA STATE SHIPBUILDING CORP LTD
- Filing Date
- 2026-04-14
- Publication Date
- 2026-07-28
AI Technical Summary
Existing technologies lack an effective way to assess the lifespan of multi-stage thermoelectric cooling components, making their aging process difficult to predict and affecting the reliability and safety of the equipment.
By employing accelerated life testing, parameter measurement and extraction, and life prediction and evaluation modules, a degradation model is established by monitoring the maximum temperature difference and AC internal resistance changes of multi-stage thermoelectric refrigeration devices, calculating pseudo-failure lifetimes, and obtaining a lifetime distribution model for lifetime prediction.
It enables rapid and accurate assessment of the lifespan of multi-stage thermoelectric refrigeration devices, reduces the need for long-term testing, improves assessment efficiency and prediction accuracy, is applicable to various working environments, and reduces resource consumption.
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Figure CN122469124A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of device lifetime assessment technology, and more specifically, relates to a multi-stage thermoelectric refrigeration device lifetime assessment system and method. Background Technology
[0002] The main function of a multi-stage thermoelectric cooling system is to achieve more efficient heat extraction and lower temperature output by connecting multiple thermoelectric cooling units in series. This design effectively improves cooling efficiency and is suitable for applications requiring large temperature differences or low-temperature environments. Multi-stage thermoelectric cooling systems have become an indispensable temperature control element for the highly reliable and stable operation of laser and infrared detectors.
[0003] However, multi-stage thermoelectric cooling components inevitably age during use due to the influence of current and the external environment. Aging of multi-stage thermoelectric cooling components mainly includes chip aging and package aging. Chip aging mechanisms include increased thermomechanical stress due to heat accumulation, expansion of chip cracks, and complete detachment of the chip adhesive layer from the bonding surface due to poor manufacturing processes. Package aging mechanisms are mainly due to material degradation caused by high-temperature operation. Aging multi-stage thermoelectric cooling components experience a decline in temperature control, leading to the burnout of other components.
[0004] However, the aging of multi-stage thermoelectric refrigeration components is not easily observed or judged directly, and due to the large number of applications, it is also difficult to determine the aging through comprehensive testing. As precision temperature control components, once aging or burnout occurs, the circuit will lose its function, causing a significant impact on equipment operation. This phenomenon poses a major hidden danger for certain critical circuits.
[0005] Although we now have a new understanding of the aging state of multi-stage thermoelectric cooling components, the aging process for these components is very lengthy, and there is currently no good way to assess the actual lifespan of such long-life devices. Summary of the Invention
[0006] In view of the deficiencies of the prior art, the purpose of this application is to provide a life assessment system and method for multi-stage thermoelectric refrigeration devices, aiming to solve the problem that the prior art lacks the ability to assess the actual life of multi-stage thermoelectric refrigeration devices.
[0007] The first aspect of this application relates to a multi-stage thermoelectric refrigeration device life assessment system, comprising: an accelerated life test module, a parameter measurement and extraction module, and a life prediction and assessment module connected in sequence. The accelerated life test module is used to complete the accelerated life test of the multi-stage thermoelectric refrigeration device by providing hot-end temperature and cold-end temperature to the multi-stage thermoelectric refrigeration device. The parameter measurement and extraction module is used to monitor the maximum temperature difference and AC internal resistance of multi-stage thermoelectric refrigeration devices during accelerated life testing; The lifetime prediction and assessment module is used to calculate the maximum temperature difference change and AC internal resistance change rate, calculate the pseudo-failure lifetime under different stress levels through the degradation model, and obtain the lifetime distribution model corresponding to the multi-stage thermoelectric refrigeration device for lifetime prediction.
[0008] In some implementations, the lifetime prediction and assessment module includes: The judgment unit is used to determine the failure of the multi-stage thermoelectric refrigeration device when it fails to reach the preset cold end temperature, the AC internal resistance change rate of the device is greater than 5%, or the maximum temperature difference change is greater than 10℃; the accelerated life test is terminated when the test time reaches the preset test time or all the devices under test fail. The lifetime calculation unit is used to calculate the pseudo-failure lifetime at different hot-end temperatures by establishing a degradation model based on the AC internal resistance and maximum temperature difference of the multi-stage thermoelectric refrigeration device. The fitting calculation unit is used to fit the pseudo-failure lifetime under different hot end temperature levels and obtain the lifetime distribution model to predict the lifetime of multi-stage thermoelectric refrigeration devices.
[0009] In some implementations, the parameter measurement and extraction module is used to set intervals to monitor the maximum temperature difference and AC internal resistance of the multi-stage thermoelectric refrigeration device.
[0010] The second aspect of this application relates to a method for evaluating the lifespan of a multi-stage thermoelectric refrigeration device, comprising the following steps: Step S1: Conduct accelerated life tests on the multi-stage thermoelectric refrigeration device and monitor the maximum temperature difference change and the rate of change of AC internal resistance; Step S2: When the multi-stage thermoelectric refrigeration device fails to reach the preset cold junction temperature, the AC internal resistance change rate is greater than 5%, or the maximum temperature difference decreases by more than 10°C, the multi-stage thermoelectric refrigeration device is deemed to have failed; the test is terminated when the test time reaches the preset test time or all the tested devices fail. Step S3: By establishing a degradation model, the pseudo-failure lifetime at different hot-end temperatures is calculated based on the AC internal resistance change rate and maximum temperature difference change of the multi-stage thermoelectric refrigeration device. Step S4: Fit pseudo-failure lifetimes at different hot-end temperature levels to obtain lifetime distribution models for lifetime prediction of multi-stage thermoelectric refrigeration devices.
[0011] In some implementations, step S1 specifically includes the following steps: Step S1.1: Extract the initial maximum temperature difference and AC internal resistance of the tested multi-stage thermoelectric refrigeration device; Step S1.2: Perform accelerated life testing on the nth cooling segment of the multi-stage thermoelectric refrigeration device; Step S1.3: After the power is cut off in the nth cooling segment of the accelerated life test process, monitor the maximum temperature difference and AC internal resistance of the multi-stage thermoelectric refrigeration device, compare them with the initial maximum temperature difference and AC internal resistance, calculate the change rate of the maximum temperature difference and the change rate of the AC internal resistance of the multi-stage thermoelectric refrigeration device, and determine whether the test should be terminated. If it is not terminated, proceed to step S1.4. Step S1.4: After the multi-stage thermoelectric refrigeration device recovers to the initial cold end temperature, n = n + 1, and proceed to step S1.2 until the test is terminated; where n is an integer greater than or equal to 1.
[0012] In some implementations, step S1.2 specifically includes the following steps: A resistance temperature detector (RTD) load is set at the hot end of the multi-stage thermoelectric cooling device, and the temperature of the hot end is monitored. Through PID feedback control, the temperature of the hot end is kept at the preset temperature, and the temperature of the hot end remains constant throughout the accelerated life test. A constant voltage and current are provided to the multi-stage thermoelectric cooling device to start cooling. The time taken for the multi-stage thermoelectric cooling device to reach the preset cold end temperature is recorded. When the preset cold end temperature is detected, the power to the multi-stage thermoelectric cooling device is cut off.
[0013] In some implementations, step S3 specifically includes the following steps: A degradation model is selected, and the estimated values of the model parameters are calculated based on the AC internal resistance change rate and the maximum temperature difference change of the multi-stage thermoelectric refrigeration device to construct the degradation model. Based on the degradation model, degradation curves are plotted. If the maximum temperature difference change of the multi-stage thermoelectric refrigeration device does not reach more than 10℃ or the change rate of AC internal resistance is less than 5% at the end of the test, the corresponding maximum temperature difference failure pseudo-life time and AC internal resistance failure pseudo-life time are calculated. The degradation curves include the working time relationship curve of refrigeration segment - reaching the preset cold end time, the degradation curve of cumulative refrigeration time - maximum temperature difference change, and the degradation curve of cumulative refrigeration time - AC internal resistance change rate.
[0014] In some implementations, step S4 specifically includes the following steps: Step S4.1: Conduct accelerated life tests on multiple sets of multi-stage thermoelectric refrigeration devices under different hot-end temperature levels, obtain degradation curves under different hot-end temperature levels, and calculate the pseudo-failure lifetime of all multi-stage thermoelectric refrigeration devices. Step S4.2: Fit the pseudo-lifetime of maximum temperature difference failure and the pseudo-lifetime of AC internal resistance failure for each group using a log-normal distribution to obtain the distribution function of the relationship between pseudo-failure lifetime and hot-end temperature stress. Step S4.3: Based on the distribution function of the relationship between pseudo-failure lifetime and hot-end temperature stress, assuming that the accelerated stress test satisfies the Arrhenius model, the relationship between lifetime and hot-end temperature is obtained by fitting, and the lifetime distribution model is completed for lifetime prediction of multi-stage thermoelectric refrigeration devices.
[0015] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: This application provides a method for assessing the lifespan of multi-stage thermoelectric cooling devices. Based on the output voltage and test parameters of the multi-stage thermoelectric cooling component sample during the aging process, a degradation model is used to calculate the pseudo-failure lifetime under different stress levels. This allows for the acquisition of a lifespan distribution model for the multi-stage thermoelectric cooling component. For the same model of multi-stage thermoelectric cooling component, the lifespan distribution model can be directly used for lifespan prediction without repeated aging processes. This facilitates the prediction of the lifespan of multi-stage thermoelectric cooling component samples under actual usage conditions, addressing the problem in existing technologies where long-term testing is required to determine the lifespan of multi-stage thermoelectric cooling devices, making lifespan prediction impossible. Attached Figure Description Figure 1 This is a diagram of a multi-stage thermoelectric refrigeration device life assessment system provided in the embodiments of this application.
[0016] Figure 2 This is the structure of the multi-stage thermoelectric refrigeration device life assessment system provided in the embodiments of this application.
[0017] Figure 3 This is a flowchart of the life assessment method for multi-stage thermoelectric refrigeration devices provided in the embodiments of this application. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0019] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. In this application, the symbol " / " indicates that the related objects are in an "or" relationship, for example, A / B means A or B.
[0020] In this application, the terms “first” and “second” are used to distinguish different objects, rather than to describe a specific order of objects.
[0021] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.
[0022] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more.
[0023] The embodiments of this application are described below with reference to the accompanying drawings.
[0024] The principle of accelerated life testing for multi-stage thermoelectric cooling devices is an intermittent life test. During the test, a fixed hot-end temperature is set for the device, while the cold-end temperature is monitored via thermocouples. The multi-stage thermoelectric cooling device begins cooling, and the time taken to reach the preset temperature at the cold end is recorded. Subsequently, the device is powered off and stops working, allowing the cold end temperature to return to its initial state. This process is repeated, and the time taken for the device to reach the preset cold end temperature each time is recorded. During the test, the changes in the maximum temperature difference and AC internal resistance of the multi-stage thermoelectric cooling device are also recorded.
[0025] Firstly, such as Figure 1 and Figure 2 As shown, this application provides a multi-stage thermoelectric refrigeration device life assessment system, including: an accelerated life test module, a parameter measurement and extraction module, and a life prediction and assessment module; The accelerated life test module is used to provide an accelerated life test platform for multi-stage thermoelectric refrigeration devices, and provides hot junction temperature, cold junction temperature and ambient temperature to the multi-stage thermoelectric refrigeration devices through a power supply. The parameter measurement and extraction module is used to monitor key performance parameters of multi-stage thermoelectric refrigeration devices, including maximum temperature difference and AC internal resistance, during accelerated life testing of multi-stage thermoelectric refrigeration devices. The lifetime prediction and assessment module is used to calculate the pseudo-failure lifetime under different stress levels based on key performance parameters including maximum temperature difference and AC internal resistance through a degradation model, thereby obtaining the lifetime distribution model corresponding to the multi-stage thermoelectric refrigeration device for lifetime prediction.
[0026] In some implementations, the lifetime prediction and assessment module includes: The judgment unit is used to determine the failure of the multi-stage thermoelectric refrigeration device when it fails to reach the preset cold end temperature, the AC internal resistance change rate of the device is greater than 5%, or the maximum temperature difference decreases by 10℃; the test is terminated when the test time reaches the preset test time or all the devices under test fail. The lifetime calculation unit is used to calculate the pseudo-failure lifetime at different hot-end temperatures by establishing a degradation model based on the AC internal resistance and maximum temperature difference of the multi-stage thermoelectric refrigeration device. The fitting calculation unit is used to fit the pseudo-failure lifetime under different hot end temperature levels and obtain the lifetime distribution model to predict the lifetime of multi-stage thermoelectric refrigeration devices.
[0027] In some implementations, the parameter measurement and extraction module is used to monitor the maximum temperature difference and AC internal resistance changes of the multi-stage thermoelectric refrigeration device at set intervals.
[0028] Secondly, such as Figure 3 As shown, this application provides a method for evaluating the lifespan of a multi-stage thermoelectric refrigeration device, including the following steps: Step S1: Conduct accelerated life tests on the multi-stage thermoelectric refrigeration device and monitor the maximum temperature difference and AC internal resistance change rate in real time; Step S2: When the multi-stage thermoelectric refrigeration device fails to reach the preset cold junction temperature, the AC internal resistance change rate is greater than 5%, or the maximum temperature difference decreases by 10℃, the multi-stage thermoelectric refrigeration device is deemed to have failed; the test is terminated when the test time reaches the preset test time or all the tested devices fail. Step S3: By establishing a degradation model, the pseudo-failure lifetime at different hot-end temperatures is calculated based on the AC internal resistance change rate and maximum temperature difference of the multi-stage thermoelectric refrigeration device. Step S4: Fit pseudo-failure lifetimes at different hot-end temperature levels to obtain lifetime distribution models for lifetime prediction of multi-stage thermoelectric refrigeration devices.
[0029] More specifically, this application provides a life assessment method based on a multi-stage thermoelectric refrigeration device life assessment system, comprising the following steps: Step 1: Use the parameter measurement and extraction module to obtain the initial maximum temperature difference of the m-th subject's multi-stage thermoelectric refrigeration device. and communication barriers .
[0030] Step 2: Place the multi-stage thermoelectric refrigeration device into the accelerated life test module for testing; More specifically, the multi-stage thermoelectric cooling device is placed in an accelerated life test module for accelerated degradation testing. The accelerated life test module provides the operating voltage and current input to the multi-stage thermoelectric cooling device. More specifically, through the accelerated life test module, a resistance temperature detector (RTD) load is set at the hot end, and the temperature of the hot end is monitored. PID feedback control is used to maintain the temperature of the hot end at a preset temperature (e.g., Th0) throughout the entire test. Simultaneously, the accelerated life test module provides the multi-stage thermoelectric cooling device with a preset constant voltage and current, maintaining these voltages and currents throughout the cooling process, thereby controlling the cooling power to remain constant.
[0031] More specifically, the entire test is conducted in a vacuum environment, eliminating the influence of external gas convection heat transfer and maintaining a stable ambient temperature. The accelerated life test module divides the entire test into n cooling segments. For the m-th device under test, within each i-th segment, the hot-end temperature Thi is first controlled within a preset initial temperature Th0, keeping the hot-end temperature constant. The system measures and records the initial cold-end temperature Tc0 at this time. Power is supplied to the multi-stage thermoelectric cooling device, enabling the device to start cooling operation, and the time tmi taken for the device to reach the preset cold-end temperature is recorded. When the preset cold-end temperature is detected, the multi-stage thermoelectric cooling device is de-energized.
[0032] Step 3: After power failure, use the parameter measurement and extraction module to monitor the maximum temperature difference of the multi-stage thermoelectric refrigeration device. and communication barriers ; and the initial maximum temperature difference and communication barriers The maximum temperature difference was obtained through comparison and calculation. and the rate of change of AC internal resistance : ; ; Step 4: After power failure, restore the cold junction to its initial cold junction temperature Tc0; and repeat steps 2 and 3 above; if the multi-stage thermoelectric cooling device fails to reach the preset cold junction temperature, the AC internal resistance change rate of the sample is greater than 5%, or the maximum temperature difference decreases by 10℃, the multi-stage thermoelectric cooling device is deemed to have failed; when the test time reaches the preset test time or all the tested devices fail, the test is terminated, and the life prediction and evaluation module is activated. Specifically, after a power outage, the cold junction temperature is restored to its initial temperature Tc0, achieving a temperature equilibrium state. This process of cooling, power outage, restoration, and parameter detection is repeated. If the cold junction temperature of the multi-stage thermoelectric refrigeration device fails to reach the preset initial cold junction temperature Tc0, or if the maximum temperature difference deviation of the multi-stage thermoelectric refrigeration device exceeds 10℃ after parameter detection... (mi>10K) or above, or the rate of change of AC internal resistance >5% ( If mi > 5%, the device is deemed to have failed, and the test is stopped. When the total cooling time (Tm) reaches the preset test time or all the tested devices fail, the test is terminated, and the life prediction and evaluation module is activated.
[0033] Step 5: The parameter measurement and extraction module analyzes the data to obtain the maximum temperature difference change of the multi-stage thermoelectric refrigeration device. and the rate of change of AC internal resistance The degradation data are shown in Table 1.
[0034] Table 1
[0035] Step Six: Use the lifetime prediction and assessment module to select different degradation models to calculate parameter estimates. More specifically, the degradation model can be selected from the following statistical models: (1); (2); (3); (4); (5); (6); in, and For the parameters to be determined in the model; In is a mathematical symbol, taken as the natural logarithm; The cumulative cooling time T - maximum temperature difference change for each sample can be obtained. Degradation curve, cumulative cooling time T - rate of change of AC internal resistance Model parameters for the degradation curve.
[0036] Step 7: Use the life prediction and assessment module to plot the working time relationship curves of the cooling segments and the time to reach the preset cold end, as well as the cumulative cooling time T and the maximum temperature difference change. Degradation curve, cumulative cooling time T - rate of change of AC internal resistance Degradation curve; If the maximum temperature difference deviation of the multi-stage thermoelectric refrigeration device does not reach more than 10℃ or the change rate of AC internal resistance is less than 5% at the end of the test, calculate the corresponding maximum temperature difference failure pseudo-life time and AC internal resistance failure pseudo-life time. Step 8: Test multiple groups of multi-stage thermoelectric cooling devices under different hot end temperature levels (Th1, Th2, ... Thn) to obtain degradation curves under different hot end temperature levels. Then calculate the pseudo lifetime L_k-m of the m-th device in the k-th group. Summarize all the pseudo lifetime data obtained, as shown in Table 2. Table 2
[0037] Step 9: Fit the pseudo-lifetime of maximum temperature difference failure and pseudo-lifetime of AC internal resistance failure for each group using a log-normal distribution; construct the likelihood function. for: ; ; in, It is the probability density function (PDF) of the normal logarithmic distribution. Maximum likelihood estimation is used to iteratively solve for the parameters of the log-normal distribution, including the mean. and standard deviation The distribution function of the relationship between pseudo-failure lifetime and hot-end temperature stress is obtained by fitting.
[0038] in, This allows us to obtain the average pseudo-lifetime at the Thk hot-end temperature. As shown in Table 3; Table 3
[0039] Step 10: Assume the accelerated stress test satisfies the Arrhenius model: By fitting the data, the relationship between lifetime and hot-end temperature can be obtained.
[0040] ; ; By substituting the hot-end temperature Tho used during component operation into the relationship between lifetime and hot-end temperature, we can obtain the operating lifetime LTo of the multi-stage thermoelectric cooling assembly at maximum temperature difference failure and the operating lifetime LRo at AC internal resistance failure. Comparing the two operating lifetime values, the smaller value is selected as the operating lifetime L.
[0041] In summary, the multi-stage thermoelectric refrigeration device life assessment system and method provided in this application facilitate the prediction of the life of multi-stage thermoelectric refrigeration devices under actual use conditions, thereby solving the problem that the existing technology requires long-term testing to determine the life of multi-stage thermoelectric refrigeration devices, making it impossible to predict the life of multi-stage thermoelectric refrigeration devices.
[0042] Example This application provides a method for evaluating the lifespan of a multi-stage thermoelectric refrigeration device, including the following steps: Step S1: Use the parameter measurement and extraction module to obtain the initial maximum temperature difference of 28 tested multi-stage thermoelectric cooling components (three groups of hot-end temperature stress, 9 tested components in each group). and communication barriers .
[0043] Step S2: Place the multi-stage thermoelectric refrigeration device into the accelerated life test module for testing; More specifically, the multi-stage thermoelectric cooling device is placed in an accelerated life test module for accelerated degradation testing. The accelerated life test module provides the operating voltage and current input to the multi-stage thermoelectric cooling device; that is, through the accelerated life test module, a resistance temperature detector (RTD) load is set at the hot end, and the temperature of the hot end is monitored. Through PID feedback control, the temperature of the hot end is kept at a preset temperature (e.g., Th0) and remains constant throughout the test. At the same time, the accelerated life test module provides the multi-stage thermoelectric cooling device with a preset constant voltage and current, and maintains the voltage and current throughout the cooling process, thereby controlling the cooling power to remain constant. More specifically, the entire experiment was conducted in a vacuum environment to eliminate the influence of external gas convection heat transfer and maintain a stable ambient temperature. The accelerated life test module consisted of 200 cooling segments. For the m-th device under test, within each i-th segment, the hot-end temperature Thi was first controlled within a preset initial temperature Th0, keeping the hot-end temperature constant, and the initial cold-end temperature Tc0 was recorded. Power was supplied to the multi-stage thermoelectric cooling device to start cooling operation, and the time tmi required for the device to reach the preset cold-end temperature was recorded. When the preset cold-end temperature was detected, the multi-stage thermoelectric cooling device was de-energized.
[0044] Step S3: After power failure, use the parameter measurement and extraction module to monitor the maximum temperature difference of the multi-stage thermoelectric refrigeration device. and communication barriers The maximum temperature difference change is obtained by comparing and calculating the initial maximum temperature difference ΔTm0 and AC internal resistance Rm0. and the rate of change of AC internal resistance : ; ; Step S4: After power failure, restore the cold junction to the initial cold junction temperature Tc0; and repeat steps S2 and S3; if the multi-stage thermoelectric cooling component fails to reach the preset cold junction temperature, the AC internal resistance change rate of the sample is greater than 5%, or the maximum temperature difference decreases by more than 10℃, the multi-stage thermoelectric cooling device is deemed to have failed; when the test time reaches the preset test time or all the tested devices fail, the test is terminated, and the life prediction and evaluation module is activated. Specifically, after a power outage, the cold junction temperature is restored to its initial temperature Tc0, achieving a temperature equilibrium state. This process of cooling, power outage, restoration, and parameter detection is repeated. If the cold junction temperature of the multi-stage thermoelectric refrigeration device fails to reach the preset initial cold junction temperature Tc0, or if the maximum temperature difference deviation of the multi-stage thermoelectric refrigeration device exceeds 10℃ after parameter detection... (mi>10K) or above, or the rate of change of AC internal resistance >5% ( If mi > 5%, the device is deemed to have failed, and the test is stopped. When the total cooling time (Tm) reaches the preset test time or all the tested devices fail, the test is terminated, and the life prediction and evaluation module is activated.
[0045] Step S5: Analyze the data using the life prediction and evaluation module to obtain the maximum temperature difference change of the multi-stage thermoelectric refrigeration device. and the rate of change of AC internal resistance Degraded data.
[0046] Step S6: Use the lifetime prediction and assessment module to select different degradation models to calculate parameter estimates; more specifically, degradation model selection: (1) in, and For the parameters to be determined in the model; In is a mathematical symbol, taken as the natural logarithm; The cumulative cooling time T - maximum temperature difference change for each device can be obtained. Degradation curve, cumulative cooling time T - rate of change of AC internal resistance Model parameters for the degradation curve.
[0047] Step S7: The life prediction and assessment module plots the working time relationship curves of the cooling segments and the time to reach the preset cold end, as well as the cumulative cooling time T and the maximum temperature difference change. Degradation curve, cumulative cooling time T - rate of change of AC internal resistance Degradation curve; If the maximum temperature difference deviation of the multi-stage thermoelectric refrigeration device does not reach more than 10℃ or the change rate of AC internal resistance is less than 5% at the end of the test, calculate the corresponding maximum temperature difference failure pseudo-life time and AC internal resistance failure pseudo-life time.
[0048] Step S8: Test multiple groups of multi-stage thermoelectric cooling devices under three different hot end temperature levels (125, 100, 75) to obtain degradation curves at different hot end temperature levels, and then calculate the pseudo lifetime L_k-m of the m-th device in the k-th group. Summarize all the obtained pseudo lifetime data as shown in Table 4. Table 4
[0049] Step S9: Fit the pseudo-lifetime data of each group using a log-normal distribution to construct a likelihood function. for: ; in, It is the probability density function (PDF) of the normal logarithmic distribution. Maximum likelihood estimation is used to iteratively solve for the parameters of the log-normal distribution, including the mean. and standard deviation The distribution function relating pseudo-lifetime to hot-end temperature stress was obtained by fitting the data. ; This allows us to obtain the average pseudo-lifetime at the Thk hot-end temperature. As shown in Table 5; Table 5
[0050] Step S10: Assume the accelerated stress test satisfies the Arrhenius model: By fitting the data, the relationship between lifetime and hot-end temperature can be obtained.
[0051] ; ; By substituting the hot-end temperature Tho used by the component during operation into the relationship between lifespan and hot-end temperature, the actual working life of the multi-stage thermoelectric refrigeration device can be predicted to be 592,416 hours (10 years).
[0052] In summary, this application provides a multi-stage thermoelectric refrigeration device lifetime assessment system and method, which calculates the lifetime under normal stress levels using a lifetime model; compared with the prior art, it has the following advantages: Improved efficiency of lifetime assessment: By using intermittent testing and periodic monitoring of key parameters, the time required for continuous testing is reduced, thereby shortening the overall assessment cycle; at the same time, by using degradation models to analyze changes in performance parameters, the actual degradation of the device can be more accurately reflected, providing reliable lifetime prediction results and enhancing prediction accuracy.
[0053] Expanded applicability: This method can predict lifespan based on different hot-end temperature conditions, and is applicable to the evaluation of multi-stage thermoelectric refrigeration devices under various working environments. It provides flexibility, and by adjusting test parameters and models, it can adapt to different types of devices or application requirements, increasing the system's versatility.
[0054] Reduced resource consumption: Intermittent testing reduces system uptime and energy consumption, saves manpower and material costs, reduces redundant testing, and the more efficient evaluation process reduces unnecessary repetitive work and optimizes resource allocation.
[0055] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A life assessment system for multi-stage thermoelectric refrigeration devices, characterized in that, include: The accelerated life testing module, parameter measurement and extraction module, and life prediction and assessment module are connected in sequence. The accelerated life test module is used to complete the accelerated life test of the multi-stage thermoelectric refrigeration device by providing hot-end temperature and cold-end temperature to the multi-stage thermoelectric refrigeration device. The parameter measurement and extraction module is used to monitor the maximum temperature difference and AC internal resistance of multi-stage thermoelectric refrigeration devices during accelerated life testing; The lifetime prediction and assessment module is used to calculate the maximum temperature difference change and AC internal resistance change rate, calculate the pseudo-failure lifetime under different stress levels through the degradation model, and obtain the lifetime distribution model corresponding to the multi-stage thermoelectric refrigeration device for lifetime prediction.
2. The life assessment system for thermoelectric refrigeration devices according to claim 1, characterized in that, The lifespan prediction and assessment module includes: The judgment unit is used to determine the failure of the multi-stage thermoelectric refrigeration device when it fails to reach the preset cold end temperature, the AC internal resistance change rate of the device is greater than 5%, or the maximum temperature difference change is greater than 10℃; the accelerated life test is terminated when the test time reaches the preset test time or all the devices under test fail. The lifetime calculation unit is used to calculate the pseudo-failure lifetime at different hot-end temperatures by establishing a degradation model based on the AC internal resistance and maximum temperature difference of the multi-stage thermoelectric refrigeration device. The fitting calculation unit is used to fit the pseudo-failure lifetime under different hot end temperature levels and obtain the lifetime distribution model to predict the lifetime of multi-stage thermoelectric refrigeration devices.
3. The life assessment system for thermoelectric refrigeration devices according to claim 1, characterized in that, The parameter measurement and extraction module is used to set intervals to monitor the maximum temperature difference and AC internal resistance of multi-stage thermoelectric refrigeration devices.
4. A method for evaluating the lifespan of a multi-stage thermoelectric refrigeration device, characterized in that, Includes the following steps: Step S1: Conduct accelerated life tests on the multi-stage thermoelectric refrigeration device and monitor the maximum temperature difference change and the rate of change of AC internal resistance; Step S2: When the multi-stage thermoelectric refrigeration device fails to reach the preset cold junction temperature, the AC internal resistance change rate is greater than 5%, or the maximum temperature difference decreases by more than 10°C, the multi-stage thermoelectric refrigeration device is deemed to have failed; the test is terminated when the test time reaches the preset test time or all the tested devices fail. Step S3: By establishing a degradation model, the pseudo-failure lifetime at different hot-end temperatures is calculated based on the AC internal resistance change rate and maximum temperature difference change of the multi-stage thermoelectric refrigeration device. Step S4: Fit pseudo-failure lifetimes at different hot-end temperature levels to obtain lifetime distribution models for lifetime prediction of multi-stage thermoelectric refrigeration devices.
5. The lifespan assessment method for multi-stage thermoelectric refrigeration devices according to claim 4, characterized in that, Step S1 specifically includes the following steps: Step S1.1: Extract the initial maximum temperature difference and AC internal resistance of the tested multi-stage thermoelectric refrigeration device; Step S1.2: Perform accelerated life testing on the nth cooling segment of the multi-stage thermoelectric refrigeration device; Step S1.3: After the power is cut off in the nth cooling segment of the accelerated life test process, monitor the maximum temperature difference and AC internal resistance of the multi-stage thermoelectric refrigeration device, compare them with the initial maximum temperature difference and AC internal resistance, calculate the change rate of the maximum temperature difference and the change rate of the AC internal resistance of the multi-stage thermoelectric refrigeration device, and determine whether the test should be terminated. If it is not terminated, proceed to step S1.
4. Step S1.4: After the multi-stage thermoelectric refrigeration device recovers to the initial cold end temperature, n = n + 1, and proceed to step S1.2 until the test is terminated; where n is an integer greater than or equal to 1.
6. The lifespan assessment method for multi-stage thermoelectric refrigeration devices according to claim 5, characterized in that, Step S1.2 specifically includes the following steps: A resistance temperature detector (RTD) load is set at the hot end of the multi-stage thermoelectric cooling device, and the temperature of the hot end is monitored. Through PID feedback control, the temperature of the hot end is kept at the preset temperature, and the temperature of the hot end remains constant throughout the accelerated life test. A constant voltage and current are provided to the multi-stage thermoelectric cooling device to start cooling. The time taken for the multi-stage thermoelectric cooling device to reach the preset cold end temperature is recorded. When the preset cold end temperature is detected, the power to the multi-stage thermoelectric cooling device is cut off.
7. The method for evaluating the lifespan of a multi-stage thermoelectric refrigeration device according to any one of claims 4 to 6, characterized in that, Step S3 specifically includes the following steps: A degradation model is selected, and the estimated values of the model parameters are calculated based on the AC internal resistance change rate and the maximum temperature difference change of the multi-stage thermoelectric refrigeration device to construct the degradation model. Based on the degradation model, degradation curves are plotted. If the maximum temperature difference change of the multi-stage thermoelectric refrigeration device does not reach more than 10℃ or the change rate of AC internal resistance is less than 5% at the end of the test, the corresponding maximum temperature difference failure pseudo-life time and AC internal resistance failure pseudo-life time are calculated. The degradation curves include the working time relationship curve of refrigeration segment - reaching the preset cold end time, the degradation curve of cumulative refrigeration time - maximum temperature difference change, and the degradation curve of cumulative refrigeration time - AC internal resistance change rate.
8. The lifespan assessment method for multi-stage thermoelectric refrigeration devices according to claim 7, characterized in that, Step S4 specifically includes the following steps: Step S4.1: Conduct accelerated life tests on multiple groups of multi-stage thermoelectric refrigeration devices under different hot-end temperature levels, obtain degradation curves under different hot-end temperature levels, and calculate the pseudo-failure lifetime time of all multi-stage thermoelectric refrigeration devices. Step S4.1: Conduct accelerated life tests on multiple sets of multi-stage thermoelectric refrigeration devices under different hot-end temperature levels, obtain degradation curves under different hot-end temperature levels, and calculate the pseudo-failure lifetime of all multi-stage thermoelectric refrigeration devices. Step S4.2: Fit the pseudo-lifetime of maximum temperature difference failure and the pseudo-lifetime of AC internal resistance failure for each group using a log-normal distribution to obtain the distribution function of the relationship between pseudo-failure lifetime and hot-end temperature stress. Step S4.3: Based on the distribution function of the relationship between pseudo-failure lifetime and hot-end temperature stress, assuming that the accelerated stress test satisfies the Arrhenius model, the relationship between lifetime and hot-end temperature is obtained by fitting, and the lifetime distribution model is completed for lifetime prediction of multi-stage thermoelectric refrigeration devices.