A multi-station thermoelectric device thermal cycle test method

Abstract

The present disclosure provides a kind of multi-station thermoelectric device thermal cycle test experimental method, the method first uses compaction device to provide total compaction force to all thermoelectric devices simultaneously before thermal cycle, total compaction force starts from 0 and is loaded in segments;Then a low temperature cycle is applied to all thermoelectric devices to be tested, so that the thermoelectric device is activated from normal temperature state;After that, the thermal cycle test begins;In the thermal cycle test, by analyzing the maximum power growth rate of each thermoelectric device in the first few cycles, it is determined whether the thermoelectric device has completely entered the working state after the low temperature activation step, if so, the thermal cycle test continues;Otherwise, it needs to be activated again;After the thermal cycle, the thermal cycle test is completed according to the parameter value change of the thermoelectric device. Using the present application can maintain the consistency of the environmental parameter change of the thermal cycle test, improve the accuracy and precision of the experiment, and at the same time improve the safety of the experiment.

Description

Technical Field

[0001] This invention belongs to the field of thermoelectric power generation technology, specifically relating to an experimental method for thermal cycling testing of multi-station thermoelectric devices. Background Technology

[0002] In the current energy system, more than half of the energy is wasted as waste heat emitted into the environment. Thermoelectric devices rely on semiconductor thermoelectric materials to convert the temperature difference between materials into a potential difference, thus realizing the conversion from heat energy to electrical energy. Thermoelectric devices can not only recover and reuse waste heat from production and daily life, but also convert clean energy sources such as geothermal energy and ocean thermal energy into heat energy, thereby improving energy utilization efficiency.

[0003] Thermal cycling experiments are used to investigate the operational capabilities and failure modes of thermoelectric devices under different maximum operating temperatures. These experiments involve conducting thermal cycling tests on thermoelectric devices under varying temperature conditions and measuring the performance changes during the thermal cycling process. Using multi-thermoelectric device thermal cycling experimental equipment allows for simultaneous cycling of multiple thermoelectric devices under the same conditions, improving testing efficiency. Furthermore, the changes between different thermoelectric devices can be compared and referenced, enhancing experimental accuracy.

[0004] However, the thermal cycling equipment applies initial downward pressure to multiple heating modules to compress the thermoelectric device through a clamping module, thereby simulating the compression situation of the thermoelectric device during actual use. Besides the initial pressure, the thermal stress generated by the thermal expansion of the heating modules and the thermoelectric device during thermal cycling is also a significant factor affecting the cycling performance of the thermoelectric device. Due to potential parameter differences between different heating modules and differences in the contact thermal resistance between the thermoelectric device and the heating module, the temperature change is inconsistent in each cycle of the thermal cycle, leading to inconsistent pressure changes in the clamping module, resulting in irregular changes in the experimental environment and reduced experimental accuracy and consistency. Summary of the Invention

[0005] In view of this, the present invention provides an experimental method for thermal cycling testing of multi-station thermoelectric devices, which can maintain the consistency of changes in thermal cycling experimental environmental parameters, improve experimental accuracy and precision, and enhance experimental safety.

[0006] To solve the above-mentioned technical problems, the present invention is implemented as follows.

[0007] An experimental method for thermal cycling testing of multi-station thermoelectric devices, the method comprising:

[0008] Step 1: Multi-stage pressurization: Place multiple thermoelectric devices to be tested on the experimental apparatus, and use a clamping device to simultaneously apply a total clamping force to all thermoelectric devices. The total clamping force is applied segment by segment starting from 0. Step 2: Low-temperature activation: Apply a low-temperature cycle to all thermoelectric devices to be tested to activate them from room temperature; the highest temperature of the low-temperature cycle is lower than the highest temperature of the thermal cycling experiment. Step 3: Thermal Cycling Experiment: Begin the thermal cycling experiment, and test the previous... The maximum power growth rate of each thermoelectric device in each cycle is analyzed. If the maximum power growth rate of any thermoelectric device is continuously greater than the set growth rate threshold, it is determined that the thermoelectric device has not fully entered the working state after the low temperature activation step and needs to be activated at low temperature again, and return to step 2; otherwise, continue the thermal cycling experiment. The value range is 2-4; During the thermal cycling experiment, the heating modules of all thermoelectric devices are controlled to rise and fall synchronously, and the heating modules and water cooling modules are protected against overheating. Step 4: Thermal cycling ends. The thermal cycling test is completed based on the changes in the thermoelectric device parameter values.

[0009] Preferably, in step 1, the total clamping force is applied segment by segment starting from 0 as follows: The total clamping force target of the thermoelectric device is The number of pressurization stages is Number of pressurization stages With total clamping force As the value increases, it increases; The value ranges from 0.12 MPa to 0.61 MPa; The value ranges from 2 to 5.

[0010] Preferably, the step-by-step loading process involves steadily increasing the total clamping force from 0 to... When the pressure change stabilizes, the total clamping force continues to increase. Repeat this process several times until the total clamping force stabilizes. .

[0011] Preferably, in step 2, the highest temperature of the low-temperature cycle is 30°C to 50°C lower than the highest temperature of the thermal cycling experiment, and the highest temperature of the low-temperature cycle is maintained for 10 to 30 minutes.

[0012] Preferably, in step 3, the maximum power growth rate of each thermoelectric device in the first three cycles is analyzed, specifically including: in each of the three cycles, the maximum power of a single thermoelectric device is recorded. , , Calculate the power growth rate from the first cycle to the second cycle using the maximum power. The power growth rate from the second cycle to the third cycle If the growth rate of any thermoelectric device and If all values ​​exceed the set growth rate threshold, it is determined that the thermoelectric device has not fully entered the working state after the low-temperature activation step, and the cycle experiment is stopped. Step 2 is repeated after cooling; otherwise, the cycle experiment continues.

[0013] Preferably, in step 3, the synchronous control of heating and cooling is as follows: During the heating process of each thermoelectric device, the reference heating rate is used. To achieve this goal, while also taking into account the temperature differences with other thermoelectric heating devices, the temperature change rate of its own heating module is adjusted in real time. This ensures that the temperature of the hot end of each thermoelectric device changes synchronously, allowing the overall clamping device to maintain stable thermal expansion and keep the pressure load on the thermoelectric device changing regularly.

[0014] Preferably, in step 3, the overheat protection control is: the temperature change rate The adjustment method is as follows:

[0015] in, The adjusted rate of temperature change, The rate of temperature change is calculated based on the actual temperature of the hot end of the thermoelectric device. The set reference temperature change rate; This refers to the actual temperature of the hot end of the thermoelectric device. It is the minimum value among all thermoelectric device hot-junction temperatures. and This refers to the sensitivity parameter.

[0016] Preferably, in step 3, the overheat protection control involves: monitoring the temperature of the heating module at the hot end of the thermoelectric device and the temperature of the water-cooling module at the cold end; when the temperature of the heating module exceeds the heating protection temperature threshold, the overheating count of the heating module is activated. Increment by 1; when the water-cooling module temperature exceeds the water-cooling protection temperature threshold, the water-cooling module overheat counter is activated. Increment by 1; if either the heating module or the water-cooling module exceeds its corresponding threshold, immediately stop the heating module and activate cooling to bring it back to its starting temperature; further determine the total overheat count. Is it greater than the set number of overheat protection cycles? If yes, stop the loop and output the fault information; otherwise, restart the loop.

[0017] Preferably, the heating protection temperature threshold is set to be 20°C to 30°C higher than the heating module temperature when the thermoelectric device reaches its maximum temperature; the water cooling protection temperature threshold is set to be 20°C to 30°C higher than the water cooling module temperature when the thermoelectric device reaches its maximum temperature.

[0018] Preferably, in step 4, the thermal cycle assessment based on changes in thermoelectric device parameter values ​​is as follows: Before the thermal cycling experiment In each cycle, the parameter values ​​of all thermoelectric devices are measured to obtain the initial measurement results; The parameter values ​​of the thermoelectric device in the last cycle are measured to obtain the measurement results after the cycle; The initial measurement results are compared with the measurement results after the cycle, and the parameter values ​​before and after the cycle are calculated as the attenuation amount, attenuation ratio and change rate.

[0019] Beneficial effects: (1) The present invention applies the clamping force segment by segment before the experiment, which can reduce the gaps caused by the expansion of the flexible thermal grease under pressure during the experiment, thus reducing the changes in the system measurement environment and improving the stability of the test.

[0020] (2) The present invention activates the thermoelectric device at low temperature before the experiment begins, so that the thermoelectric device reaches the working state at the beginning of the cycle and the maximum power value measured at the beginning of the cycle is closer to the optimal state.

[0021] (3) The synchronous temperature control of the cyclic process of the present invention makes the pressure change stable, taking into account the difference between the actual temperature change rate and the reference temperature change rate and the temperature difference between each heating module, so that the temperature change of the heating block with a higher temperature is slower than that of the heating block with a lower temperature, thus reducing the temperature inconsistency between each heating block.

[0022] (4) The overheat protection function during the cycle of this invention avoids abnormal temperature rise caused by overheating of the thermocouple in the heating block during the experiment, and prevents the temperature of the thermoelectric device from rising abnormally due to the failure of the water-cooling module to be discharged in time. This prevents the performance of the thermoelectric device from being affected by excessive temperature and ensures experimental safety when the experiment is unattended for a long time. Attached Figure Description

[0023] Figure 1 This is a flowchart of the experimental method for thermal cycling testing of the multi-station thermoelectric device of the present invention.

[0024] Figure 2 for Figure 1 Flowchart of overheat protection control.

[0025] Figure 3 for Figure 1 Schematic diagram of synchronous temperature rise and fall control.

[0026] Figure 4 This is a schematic diagram of the experimental system structure for thermal cycling testing of the multi-station thermoelectric device of the present invention. Detailed Implementation

[0027] This invention provides an experimental method for thermal cycling testing of multi-station thermoelectric devices. Figure 4 The system structure shown includes a clamping module, a heating module, an experimental setup, a water-cooling module, and a measurement and control module. The experimental setup has multiple workstations, each holding a thermoelectric device to be tested. The parameters of the thermoelectric devices are measured in real time and transmitted to the measurement and control module. The number of heating and water-cooling modules is the same as the number of thermoelectric devices, providing hot-end heating and cold-end water cooling, respectively. The heating module provides the hot-end temperature for the thermoelectric devices during thermal cycling and is controlled by the measurement and control module during operation. The water-cooling module provides the cold-end temperature for the thermoelectric devices during thermal cycling and cools the heating module during cooling; it is also controlled by the measurement and control module during operation. The clamping module provides clamping force to all thermoelectric devices through a central clamping device. During pressurization, the measurement and control module controls the stable pressurization. An initial clamping force is applied before the experiment to ensure that the clamping force does not fall below this value during the experiment. During the cyclic experiment, the clamping force value changes periodically with the thermal expansion of the thermoelectric devices, simulating the pressure environment of the thermoelectric devices in actual use. The measurement and control module is used to control the clamping module, heating module and water cooling module, and record the parameters of each thermoelectric device during the experiment.

[0028] The core idea of ​​this invention is to fully consider the changes in environmental parameters during simultaneous thermal cycling of multiple thermoelectric devices and design a test method that ensures stable changes in experimental environmental parameters. The design for stable changes in environmental parameters includes the following aspects: (1) The flexible thermally conductive silicone grease between the thermoelectric device and the water-cooling module can cause gaps when pressure is applied by the compression module, leading to changes in the system's measurement environment. Furthermore, the flexible thermally conductive silicone grease may have slight differences between different thermoelectric devices, resulting in varying gaps and different measurement environments for each device. These differences in gaps also lead to variations in heat conduction channels and force transmission channels after thermal expansion, thus reducing experimental stability. Therefore, this invention gradually pressurizes the thermoelectric device under test before the start of the cyclic experiment, ensuring a stable pressure gradient. This reduces the gaps caused by the expansion of the flexible thermally conductive silicone grease during the experiment, thereby improving experimental stability.

[0029] (2) In the first few cycles of the cyclic experiment, the maximum power value of the thermoelectric device gradually increases and does not stabilize at the optimal state. If the parameter values ​​under this state are used for evaluation data calculation and comparison, it may lead to increased errors in power generation capacity and lifespan prediction, thus reducing the accuracy of the experiment. To this end, the present invention adds a low-temperature cycle activation step for the thermoelectric device before the start of the cyclic experiment, so that the thermoelectric device reaches the working state at the beginning of the cycle, and the maximum power value measured at the beginning of the cycle is closer to the optimal state, thereby improving the accuracy of the experiment.

[0030] (3) Considering that the inconsistent heating process of each heating module during the cyclic experiment leads to inconsistent and unstable environmental parameters, this invention, in controlling the heating of each thermoelectric device, takes the reference heating rate as the target while also taking into account the temperature differences with other thermoelectric devices, and adjusts its own heating rate in real time to ensure that the hot end temperature of each thermoelectric device changes synchronously. This invention, through the heating and cooling control of the heating modules, ensures that the hot end temperature of each thermoelectric device changes stably and synchronously. Simultaneously, the thermal stress generated by the thermal expansion of the heating modules changes regularly and synchronously, thereby ensuring stable thermal expansion of the clamping device and maintaining a regular change in the pressure load on the thermoelectric devices. This avoids irregular pressure rises and falls caused by parameter differences between different heating modules and differences in contact between the heating module and the thermoelectric devices, improving the accuracy and consistency of the test results.

[0031] (4) The present invention also implements overheat protection during the cycle. By counting faults, the influence of accidental temperature overshoot on the monitoring program can be reduced. If the fault occurs repeatedly, the experiment will be stopped immediately. The overheat protection process proposed in the present invention can effectively avoid the local temperature rise caused by the overheating of thermocouples in the heating module or the failure of the water cooling module during the experiment, which prevents heat from being dissipated in time. At the same time, it avoids the influence of short-term overshoot that may occur in temperature control on overheat protection.

[0032] The above improvements enable the present invention to maintain consistency in the variation of experimental environment parameters and improve experimental accuracy and precision.

[0033] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] Figure 2 This is a flowchart of the experimental method for thermal cycling testing of the multi-station thermoelectric device in this invention. As shown in the figure, the experimental method includes: Step 101: Multi-stage pressurization: Place multiple thermoelectric devices to be tested on the experimental apparatus, and use a total clamping device to simultaneously provide a total clamping force to all thermoelectric devices. The total clamping force is applied segment by segment starting from 0.

[0035] In this embodiment, the target total clamping force of the thermoelectric device is set as follows: The number of pressurization stages is Number of pressurization stages With total clamping force The value of increases as it increases. The amount of pressure applied each time is... .

[0036] Optionally, The value ranges from 0.12 MPa to 0.61 MPa; The value ranges from 2 to 5. Within the specified range, the maximum power of the thermoelectric device can be kept within its maximum range. If the pressure value is too high, it may damage the thermoelectric device. If the pressure value is too low, the maximum power of the thermoelectric device will decrease.

[0037] For example, the clamping force of thermoelectric devices The values ​​are 0.24MPa, 0.31MPa, or 0.37MPa, etc. Number of clamping force stages. along with The value increases as the value increases, if Choose 0.37MPa. The possible value is 4.

[0038] The method for gradually increasing the pressure can be as follows: steadily increase the total clamping force from 0 to... When the pressure change stabilizes, continue to increase Adjust the clamping force; repeat the above steps until the total clamping force stabilizes at [value missing]. .

[0039] For example, the criterion for stable pressure change can be: the pressure change value is less than 0.01 MPa / s. If the pressure change value is greater than 0.01 MPa / s, then when the pressure change value deviates from the set value by 0.12 MPa, the pressure value is brought back to the set value until the pressure change value is less than 0.01 MPa / s.

[0040] The advantage of this step is that the gradual pressurization method before thermal cycling can reduce the voids caused by the expansion of flexible thermal grease under pressure during the experiment, which leads to changes in the system measurement environment and improves the stability of the test.

[0041] Step 102: Low-temperature activation: Apply a low-temperature cycle to all thermoelectric devices to restore them from their static state at room temperature to their operating state, i.e., activate them. Here, the highest temperature of the low-temperature cycle is lower than the highest temperature of the thermal cycling experiment.

[0042] Preferably, the parameters for the low-temperature cycle are set as follows: the maximum temperature of the low-temperature cycle is 30°C to 50°C lower than the maximum temperature of the thermal cycling experiment, and the holding time of the maximum temperature in the low-temperature cycle is 10 to 30 minutes. The setting of the maximum temperature of the low-temperature cycle requires special design. If it is too much lower than the maximum temperature of the thermal cycling experiment, the thermoelectric device cannot be effectively activated, and it will not reach its working state at the start of the cycle, resulting in a lower measured maximum power value. If it is too little lower than the maximum temperature of the thermal cycling experiment, it can already approximate the cycle in the experiment, causing errors in the basis for the parameter evolution and cycle count in the cycle experiment, thus affecting the accuracy of the experiment.

[0043] For example, the parameters for the low-temperature cycle are set as follows: the maximum temperature of the low-temperature cycle is 30°C, 40°C, or 50°C lower than the maximum temperature of the thermal cycling experiment, etc. The maximum temperature holding time is 10 min, 20 min, or 30 min, etc.

[0044] Optionally, the maximum temperature of the thermal cycle is between 200°C and 350°C, and the end temperature of the thermal cycle cooling is between 10°C and 35°C. For example, the maximum temperature of the thermal cycle is 250°C, and the end temperature of the thermal cycle cooling is 30°C.

[0045] The thermal cycling experiment will now begin, including steps 103, 104, and 105. Step 105 is the thermal cycling experiment step, during which overheat protection, simultaneous heating and cooling of the heating device, and parameter acquisition are continuously implemented. In the initial stage of step 105, steps 103 and 104 are executed to assess the activation effect.

[0046] Step 103: Start the thermal cycle, before the thermal cycle begins Within each cycle, the parameter values ​​of all thermoelectric devices are measured for each cycle to obtain initial measurement results. Here, The value ranges from 2 to 4, and in this embodiment, it is preferred. 3.

[0047] Optionally, the number of thermal cycles N is from 10 to 5000, and the holding time at the highest thermal temperature during the thermal cycle is from 0 min to 5 min. The parameters of the thermoelectric device for the first three cycles are measured as follows: open-circuit voltage U, internal resistance R, and maximum power P. For example, the number of thermal cycles N is selected as 10, 100, 500, or 1500, and the holding time at the highest thermal temperature during the thermal cycle is 0 min or 3 min.

[0048] Step 104: Determine whether the initial value measurement has increased significantly, thereby determining the low-temperature activation effect.

[0049] In this step, the previous The maximum power growth rate of each thermoelectric device in each cycle is analyzed. If the maximum power growth rate of any thermoelectric device is continuously greater than the set growth rate threshold, it is determined that the thermoelectric device has not fully entered the working state after the low temperature activation step and needs to be activated at low temperature again, and the process returns to step 102; otherwise, the thermal cycling experiment in step 105 continues.

[0050] by For example, the analysis of the maximum power growth rate of each thermoelectric device in the first three cycles is as follows: In each of the three cycles, the maximum power is recorded at the same measurement point for a single thermoelectric device, denoted as . , , The growth rate is calculated using the maximum power:

[0051] in, This represents the power growth rate from the first cycle to the second cycle. This represents the power growth rate from the second cycle to the third cycle.

[0052] If growth rate and If all growth rates exceed the set growth rate threshold (5% in this embodiment), it is determined that the thermoelectric device has not fully entered the working state after the low-temperature activation step, the cycle experiment is stopped, and step 102 is repeated after cooling. If one of the growth rates is less than 5%, the cycle experiment in step 105 continues.

[0053] Here, growth rate and If all values ​​are greater than 5%, it indicates that the thermoelectric device has not fully recovered to its working state and continues to be activated during the cycle, resulting in unstable maximum power.

[0054] Step 105: During the thermal cycling experiment, the heating module of the system is controlled to rise and fall synchronously, and the heating module and water cooling module are protected against overheating.

[0055] Overheat protection control will be discussed in the following section. Figure 2 A detailed description will be provided below, with synchronous temperature rise and fall control discussed in conjunction with the following text. Figure 3 Provide a detailed description.

[0056] Step 106: Measure the parameter values ​​of the thermoelectric device in the cycle before the end of the cyclic experiment as the measurement results after the cycle.

[0057] Optionally, the cycle parameters of the thermoelectric device in the last cycle are measured as follows: open-circuit voltage U, internal resistance R, and maximum power P.

[0058] Step 107: Compare the measured initial value of the cycle with the value after the cycle to complete the thermal cycling test.

[0059] For example, the comparison method is as follows: compare the initial measurement results with the measurement results after the cycle, and calculate the parameter value attenuation, attenuation ratio, and rate of change before and after the cycle. Specifically: Attenuation before and after cycling: Subtract the corresponding cycle measurement results from the initial measurement results, including open-circuit voltage, internal resistance, and maximum power; The attenuation ratio before and after cycling: Subtract the corresponding measurement results after cycling from the initial measurement results, including open-circuit voltage, internal resistance and maximum power, divide the difference by the initial measurement results and convert it into a percentage; Rate of change before and after cycling: Subtract the corresponding measurement results after cycling from the initial measurement results including open-circuit voltage, internal resistance and maximum power, divide the difference by the number of thermal cycles N, and convert it into a percentage.

[0060] This concludes the process.

[0061] Figure 2 This is a flowchart of the overheat protection control process in the experimental method for thermal cycling testing of multi-station thermoelectric devices in this invention. The main idea of ​​this test method is to monitor the temperature of the heating module at the hot end and the water-cooling module at the cold end of the thermoelectric device; when the temperature of the heating module exceeds the heating protection temperature threshold, the overheating count of the heating module is activated. Increment by 1; when the water-cooling module temperature exceeds the water-cooling protection temperature threshold, the water-cooling module overheat counter is activated. Increment by 1; if either the heating module or the water-cooling module exceeds its corresponding threshold, immediately stop heating the thermoelectric heating module and activate cooling to bring the heating module back to its starting temperature; further determine the total overheat count. Is it greater than the set number of overheat protection cycles? If yes, stop the loop and output the fault information; otherwise, restart the loop.

[0062] like Figure 2 As shown, the overheat protection control process includes the following steps: Step 201: Measure the temperature of the heating module (i.e., hot end temperature) and the temperature of the water-cooling module (i.e., cold end temperature) in real time using thermocouples between the heating module and the water-cooling module, and use these as input parameters for overheat protection.

[0063] Step 202: Compare the heating module temperature measured in step 201 with the set heating protection temperature threshold: If the measured temperature of the heating module is higher than the set heating protection temperature threshold, proceed to step 203. If the measured temperature of the heating module is lower than or equal to the set heating protection temperature threshold, proceed to step 204.

[0064] Optionally, the heating protection temperature threshold is set to be 20°C to 30°C higher than the heating module temperature when the thermoelectric device reaches its maximum temperature. If the value is lower than this range, short-term overshoot may easily occur during temperature control, leading to misjudgment of overheat protection. If the value is higher than this range, the temperature control may be less sensitive to abnormal temperature increases, increasing experimental risks. For example, the heating module protection temperature value is set to be 20°C or 30°C higher than the heating block temperature when the thermoelectric device reaches its maximum temperature.

[0065] Step 203: At this point, the heating module temperature has exceeded the heating protection temperature threshold, triggering the heating module overheat counter. Add 1, then proceed to step 206.

[0066] Overheating count of the heating module at the start of the experiment The initial value is 0. After the experiment, the heating module overheating count is set. Return to 0.

[0067] Step 204: At this point, the heating module temperature has not exceeded the heating protection temperature threshold. Analyze the water cooling module temperature: Compare the water cooling module temperature measured in step 201 with the set water cooling protection temperature threshold. If the measured temperature of the water-cooled module is higher than the set water-cooling protection temperature threshold, proceed to step 205. If the measured temperature of the water-cooled module is lower than or equal to the set water-cooling protection temperature threshold, proceed to step 201 to continue temperature monitoring.

[0068] Optionally, the water-cooling protection temperature threshold is set to be 20°C to 30°C higher than the water-cooling module temperature when the thermoelectric device reaches its maximum temperature.

[0069] Step 205: At this point, the water-cooled module temperature has exceeded the water-cooling protection temperature threshold, triggering the water-cooled module overheat counter. Add 1, then proceed to step 206.

[0070] At the start of the experiment, the water-cooled module overheated. The initial value is 0. After the experiment, the water-cooled module overheating count is set. Return to 0.

[0071] Step 206: If the temperature of the heating module or water cooling module exceeds the protection temperature value, the system will immediately stop the heating module from working and start the cooling process to cool the heating module down to the start heating temperature.

[0072] Step 207: Calculate the overheat count of the heating module Overheating count of water-cooled module The sum of: if the superheat parameters and Not exceeding the set number of overheat protection cycles (For example If the overheating parameters and If the value is greater than 2, then proceed to step 209.

[0073] Step 208: Continue the thermal cycling experiment. The experimental parameters and number of cycles are inherited from the parameters before the experiment stopped in step 206. Return to step 201.

[0074] Step 209: Stop the heating module from operating, cease the interrupted thermal cycling experiment, and output fault information and the overheating parameter values ​​of both the heating module and the water-cooling module. .

[0075] The overheat protection monitoring in the multi-thermoelectric device thermal cycling test method of this invention aims to prevent abnormal temperature rises caused by overheating of thermocouples in the heating module and the inability to timely dissipate faulty temperatures in the water-cooling module, thus avoiding abnormal temperature increases in the thermoelectric devices. This prevents excessively high temperatures from affecting the performance of the thermoelectric devices and ensures experimental safety during long-term unattended experiments.

[0076] Figure 3 This is a flowchart illustrating the synchronous temperature rise and fall control of the heating module in the experimental method for thermal cycling evaluation of multi-station thermoelectric devices in this invention. This control process ensures that each thermoelectric device maintains a reference temperature rise rate during the heating process. To achieve this goal, while also taking into account the temperature differences with other thermoelectric heating devices, the temperature change rate of its own heating module is adjusted in real time. This ensures that the temperature of the hot end of each thermoelectric device changes synchronously, allowing the overall clamping device to maintain stable thermal expansion and keep the pressure load on the thermoelectric device changing regularly.

[0077] like Figure 3 As shown, the synchronous temperature rise and fall control process includes the following steps: Step 301: The temperature sensor of each heating module measures the temperature parameter value of the heating module in real time, that is, the hot end temperature parameter of the hot spot module.

[0078] Optionally, the temperature parameter value may include the temperature value and the rate of temperature change.

[0079] Step 302: Calculate the rate of temperature change using the temperature parameters of the heating module. .

[0080] Rate of temperature change The following temperature change rate adjustment model is used to calculate and output the updated temperature change rate: The temperature change rate adjustment model is as follows:

[0081] in, For the updated rate of temperature change, Based on the actual temperature of the hot end of the hot-touch device The rate of temperature change calculated from the temperature parameters of the heating module. The set reference temperature change rate, This refers to the actual temperature of the hot end of the thermoelectric device. It is the minimum temperature among all heating modules. and This refers to the sensitivity parameter.

[0082] The temperature change rate adjustment model takes into account the difference between the actual temperature change rate and the reference temperature change rate, as well as the temperature difference between each heating module. This makes the temperature change of the heating block with a higher temperature slower than that of the heating block with a lower temperature, thus reducing the temperature inconsistency between the heating blocks.

[0083] Step 303: Update the temperature parameters The input is sent to the control module of the heating module to adjust the rate of temperature change of the heating module.

[0084] For example, the heating module adjusts the rate of temperature change by adjusting the input voltage of the internal heating thermocouple when heating up and adjusting the flow rate of the cooling water inlet of the heating block when cooling down.

[0085] Based on the experimental method for thermal cycling testing of multi-station thermoelectric devices according to the present invention, Figure 4 The functionality of each module in the experimental system has been adaptively adjusted to the following mode: The measurement and control module is used to control the clamping module, heating module and water cooling module, provide overheat protection monitoring and synchronous control of heating module temperature rise and fall, and record the parameters of each thermoelectric device in the experiment.

[0086] Among these, the clamping force parameter, experimental cycle and temperature parameters, and heating / cooling parameters need to be manually entered and adjusted. The clamping force parameter includes: the initial thermoelectric device clamping force. Number of clamping force stages With pressure change value The experimental cycle and temperature parameters include: number of thermal cycles N, duration of holding the highest temperature during the thermal cycle t, highest temperature during the thermal cycle Th, end temperature of the thermal cycle cooling Tc, and highest temperature during the activation cycle. and the highest temperature holding time during the activation cycle Temperature rise and fall parameters include: the rate of change of the reference temperature. Sensitivity parameters and .

[0087] The clamping module provides clamping force to all thermoelectric elements through a main clamping device. During pressurization, the pressure is controlled and stabilized by the measurement and control module. After applying the initial clamping force before the experiment, the clamping force is ensured to be no lower than this value during the experiment. During the cyclic experiment, the clamping force value will change periodically with the thermal expansion of thermoelectric devices, etc., to simulate the pressure environment of thermoelectric devices in actual use.

[0088] The heating module is used to provide the hot end temperature of the thermoelectric device for thermal circulation. During operation, it is controlled by the measurement and control module, which continuously adjusts the rate of temperature change so that the actual rate of temperature change of the heating block is close to the set reference rate of temperature change. At the same time, it takes into account the temperature of other heating blocks to reduce the difference in the rate of temperature change of different heating blocks, thereby maintaining the regularity and stability of the clamping force.

[0089] The experimental module holds the thermoelectric device to be tested, and the measuring device measures the parameters of the thermoelectric device in real time and transmits them to the measurement and control module.

[0090] The water-cooling module is used to provide the cold end temperature of the thermoelectric device during thermal cycling, and to cool the heating module during cooling. It is controlled by the measurement and control module during operation. During the cycle experiment, it provides cooling water with a stable temperature and flow rate to the thermoelectric device to keep the cold end temperature of the thermoelectric device constant during the experiment.

[0091] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An experimental method for thermal cycling testing of multi-station thermoelectric devices, characterized in that, The method includes: Step 1: Multi-stage pressurization: Place multiple thermoelectric devices to be tested on the experimental apparatus, and use a clamping device to simultaneously apply a total clamping force to all thermoelectric devices. The total clamping force is applied segment by segment starting from 0. Step 2: Low-temperature activation: Apply a low-temperature cycle to all thermoelectric devices to be tested to activate them from room temperature; the highest temperature of the low-temperature cycle is lower than the highest temperature of the thermal cycling experiment. Step 3: Thermal Cycling Experiment: Begin the thermal cycling experiment, and test the previous... The maximum power growth rate of each thermoelectric device in each cycle is analyzed. If the maximum power growth rate of any thermoelectric device is continuously greater than the set growth rate threshold, it is determined that the thermoelectric device has not fully entered the working state after the low temperature activation step and needs to be activated at low temperature again, and return to step 2; otherwise, continue the thermal cycling experiment. The value range is 2-4; During the thermal cycling experiment, the heating modules of all thermoelectric devices are controlled to rise and fall synchronously, and the heating modules and water cooling modules are protected against overheating. Step 4: Thermal cycling ends. The thermal cycling test is completed based on the changes in the thermoelectric device parameter values.

2. The method as described in claim 1, characterized in that, In step 1, the total clamping force is applied segment by segment starting from 0 as follows: The total clamping force target of the thermoelectric device is The number of pressurization stages is Number of pressurization stages With total clamping force As the value increases, it increases; The value ranges from 0.12 MPa to 0.61 MPa; The value ranges from 2 to 5.

3. The method as described in claim 1, characterized in that, The step-by-step loading process involves steadily increasing the total clamping force from 0 to... When the pressure change stabilizes, the total clamping force continues to increase. Repeat this process several times until the total clamping force stabilizes. .

4. The method as described in claim 1, characterized in that, In step 2, the highest temperature of the low-temperature cycle is 30°C to 50°C lower than the highest temperature of the thermal cycling experiment, and the highest temperature of the low-temperature cycle is maintained for 10 to 30 minutes.

5. The method as described in claim 1, characterized in that, Step 3 involves analyzing the maximum power growth rate of each thermoelectric device in the first three cycles. Specifically, this includes recording the maximum power of a single thermoelectric device in each of the three cycles. , , Calculate the power growth rate from the first cycle to the second cycle using the maximum power. The power growth rate from the second cycle to the third cycle If the growth rate of any thermoelectric device and If all values ​​exceed the set growth rate threshold, it is determined that the thermoelectric device has not fully entered the working state after the low-temperature activation step, and the cycle experiment is stopped. Step 2 is repeated after cooling; otherwise, the cycle experiment continues.

6. The method as described in claim 1, characterized in that, In step 3, the synchronous control of heating and cooling is as follows: During the heating process of each thermoelectric device, the reference heating rate is used. To achieve this goal, while also taking into account the temperature differences with other thermoelectric heating devices, the temperature change rate of its own heating module is adjusted in real time. This ensures that the temperature of the hot end of each thermoelectric device changes synchronously, allowing the overall clamping device to maintain stable thermal expansion and keep the pressure load on the thermoelectric device changing regularly.

7. The method as described in claim 6, characterized in that, In step 3, the overheat protection control is: the rate of temperature change The adjustment method is as follows: in, The adjusted rate of temperature change, The rate of temperature change is calculated based on the actual temperature of the hot end of the thermoelectric device. The set reference temperature change rate; This refers to the actual temperature of the hot end of the thermoelectric device. It is the minimum value among all thermoelectric device hot-junction temperatures. and This refers to the sensitivity parameter.

8. The method as described in claim 1, characterized in that, In step 3, the overheat protection control involves monitoring the temperature of the heating module at the hot end of the thermoelectric device and the temperature of the water-cooling module at the cold end; when the temperature of the heating module exceeds the heating protection temperature threshold, the overheating count of the heating module is activated. Increment by 1; when the water-cooling module temperature exceeds the water-cooling protection temperature threshold, the water-cooling module overheat counter is activated. Increment by 1; if either the heating module or the water-cooling module exceeds its corresponding threshold, immediately stop the heating module and activate cooling to bring it back to its starting temperature; further determine the total overheat count. Is it greater than the set number of overheat protection cycles? If so, stop the loop and output the fault information; Otherwise, restart the loop.

9. The method as described in claim 8, characterized in that, The heating protection temperature threshold is set to be 20°C to 30°C higher than the heating module temperature when the thermoelectric device reaches its maximum temperature; the water cooling protection temperature threshold is set to be 20°C to 30°C higher than the water cooling module temperature when the thermoelectric device reaches its maximum temperature.

10. The method as described in claim 1, characterized in that, In step 4, the thermal cycle assessment based on changes in thermoelectric device parameter values ​​is as follows: Before the thermal cycling experiment In each cycle, the parameter values ​​of all thermoelectric devices are measured to obtain the initial measurement results; The parameter values ​​of the thermoelectric device in the last cycle are measured to obtain the measurement results after the cycle; The initial measurement results are compared with the measurement results after the cycle, and the parameter values ​​before and after the cycle are calculated as the attenuation amount, attenuation ratio and change rate.

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