CN116828954A - Method for improving output performance of thermoelectric generator and relieving parasitic loss - Google Patents
Method for improving output performance of thermoelectric generator and relieving parasitic loss Download PDFInfo
- Publication number
- CN116828954A CN116828954A CN202310806407.2A CN202310806407A CN116828954A CN 116828954 A CN116828954 A CN 116828954A CN 202310806407 A CN202310806407 A CN 202310806407A CN 116828954 A CN116828954 A CN 116828954A
- Authority
- CN
- China
- Prior art keywords
- thermoelectric generator
- circuit board
- type
- output performance
- improving
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 48
- 230000003071 parasitic effect Effects 0.000 title claims abstract description 26
- 239000000463 material Substances 0.000 claims abstract description 43
- 239000002245 particle Substances 0.000 claims abstract description 28
- 238000002360 preparation method Methods 0.000 claims abstract description 11
- 238000004806 packaging method and process Methods 0.000 claims abstract description 9
- 238000003466 welding Methods 0.000 claims abstract description 8
- 239000004065 semiconductor Substances 0.000 claims abstract description 3
- 235000012431 wafers Nutrition 0.000 claims description 14
- 238000009713 electroplating Methods 0.000 claims description 13
- 239000000919 ceramic Substances 0.000 claims description 9
- 230000000116 mitigating effect Effects 0.000 claims description 9
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 7
- 229910052802 copper Inorganic materials 0.000 claims description 7
- 239000010949 copper Substances 0.000 claims description 7
- 238000005520 cutting process Methods 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 229910000679 solder Inorganic materials 0.000 claims description 5
- 238000005476 soldering Methods 0.000 claims description 4
- 230000008719 thickening Effects 0.000 claims description 4
- 230000004888 barrier function Effects 0.000 claims description 3
- 238000005530 etching Methods 0.000 claims description 3
- 238000005498 polishing Methods 0.000 claims description 3
- 238000007639 printing Methods 0.000 claims description 3
- 238000010023 transfer printing Methods 0.000 claims description 3
- 229910000831 Steel Inorganic materials 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 claims description 2
- 239000010959 steel Substances 0.000 claims description 2
- 238000011049 filling Methods 0.000 abstract description 18
- 238000005457 optimization Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 229910052797 bismuth Inorganic materials 0.000 description 3
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000004088 simulation Methods 0.000 description 3
- XSOKHXFFCGXDJZ-UHFFFAOYSA-N telluride(2-) Chemical compound [Te-2] XSOKHXFFCGXDJZ-UHFFFAOYSA-N 0.000 description 3
- 238000000151 deposition Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Abstract
The invention discloses a method for improving output performance of a thermoelectric generator and relieving parasitic loss, which comprises the following steps: s1: the preparation step of the copper-clad circuit board of the thermoelectric generator comprises the following steps of S2: the preparation method of the P type/N type semiconductor material particles comprises the following steps of: and welding and packaging, namely alternately welding the P-type and N-type material particles on the copper-clad circuit board of the thermoelectric generator prepared in the step S1, and finishing insulating packaging of the edge of the circuit board. The method improves the particle density of the thermoelectric material, thereby increasing the filling rate, so that the thermoelectric generator prepared by the method has high performance due to high filling rate, and realizes smaller circuit current value and lower parasitic loss under the same condition.
Description
Technical Field
The invention belongs to the technical field of integrated circuits, and particularly relates to a method for improving output performance of a thermoelectric generator and relieving parasitic loss.
Background
In recent years, bi 2 Te 3 The representative room temperature thermoelectric materials have not been broken through, the ZT value of the materials is generally about 1.0, and some materials with better performance (ZT-1.6) have not been put into commercial use. Although bismuth telluride-based devices have wide application in the refrigeration field, the power generation field of great interest is limited by low performance and is in the interest of being in the base application. The theoretical output performance of the thermoelectric generator is determined by materials, but the actual output performance is generated by coupling the materials and components of each part, wherein factors such as length-diameter ratio, contact resistance, contact thermal resistance, electrode thickness, ceramic plate material, filling rate and the like of the materials have influence on the actual output.
Common commercial devices can meet some energy supply requirements in higher temperature ladders (more than 50K), but under the working condition of low temperature difference, particularly around room temperature, the devices have few practical applications. Such devices generally involve optimization of material aspect ratio, contact resistance, contact thermal resistance, and electrode thickness as described above during the development stage. As shown in fig. 1, (1) (2) are P-type and N-type bismuth telluride-based materials, respectively, having cross-sectional areas and heights a and l, respectively; (3) for the contact layer, both current and heat flow are required to pass through the contact surface; (4) the electrodes are typically made of copper. The optimization of the aspect ratio (l/a) is mainly to balance the relation between the open circuit voltage and the internal resistance. The larger l/a, the larger the gradient temperature, the larger the output voltage, but as l/a increases, the resistance of the material increases. Therefore, it is necessary to find a suitable value of l/a, which is also the most common means of optimization at the present time. The contact optimization and the electrode thickness optimization are both used for relieving heat loss and electric loss, and the selection of an insulating substrate with good heat conduction performance has great significance for practical application and production.
The idea of the above method is summarized: the theoretical performance of the material is completely released as much as possible, and the energy loss is greatly reduced. Although the above methods are all scientific and effective, the actual size cannot be designed according to the theoretical length-diameter ratio in consideration of the use condition and the brittleness of part of the materials; moreover, good contact often requires costly, difficult and cumbersome technological implementation.
Increasing the cross-sectional area of the material particles to reduce the internal resistance of the device and thereby mitigate heat radiation losses is also considered to be a method of improving thermoelectric generator performance. The method can be attributed to the fill-rate effect, i.e., the greater the fill rate, the greater the output power, as shown in equation (1). The formula takes into account the filling rate (f), the ceramic plate area (A), the material height (l), the material cross-sectional area (a), the contact resistivity (ρ c ) Thermal conductivity in contact (κ) c ) Resistance value of individual electrode (r e ) Actual temperature difference (T) 0 ) Thickness of contact layer (l) c ) And the effect of the material's performance parameters (seebeck coefficient α, thermal conductivity κ, and resistivity ρ) on maximum output power.
The method is experimentally verified that the maximum output power of the material is indeed in an upward trend along with the increase of the cross-sectional area of the material, but the result is similar to the expected P max The "difference from f is significant because most of the power is lost by parasitic resistances in the circuit.
In summary, in the method of optimizing the performance of a thermoelectric generator, both the improvement of output performance and the mitigation of energy loss are performed separately. The method can be carried out in a laboratory, and can realize quality change, but the method has a long way to put into practical production and even use. Based on materials, if the optimization of the length-diameter ratio can cause the effective temperature difference to be changed in quality, the large voltage formed by the serial connection of high-density material particles is the quantity, but the prior method is rarely related to experimental samples aiming at the conditions of different temperature differences and particle densities. The contact optimization is an engineering with large difficulty coefficient, high cost and complicated process, and although the processes such as sintering, electroplating and the like can effectively relieve contact resistance and contact thermal resistance, the brazing process is the main process in actual production.
In view of this, there is a need for a method that can both improve output performance and mitigate energy loss.
Disclosure of Invention
The invention aims at: in order to overcome the problems in the prior art, a method for improving the output performance of a thermoelectric generator and relieving parasitic loss is disclosed, and the particle density of a thermoelectric material is improved by the method so as to increase the filling rate, so that the thermoelectric generator prepared by the method has high performance due to high filling rate, and smaller circuit current value and lower parasitic loss under the same condition are realized.
The aim of the invention is achieved by the following technical scheme:
a method of improving thermoelectric generator output performance and mitigating parasitic losses, the method comprising the steps of:
s1: a preparation step of a copper-clad circuit board of a thermoelectric generator,
s2: a preparation step of P type/N type semiconductor material particles,
s3: and welding and packaging, namely alternately welding the P-type and N-type material particles on the copper-clad circuit board of the thermoelectric generator prepared in the step S1, and finishing insulating packaging of the edge of the circuit board.
According to a preferred embodiment, step S1 comprises: and carrying out magnetic control copper coating, electroplating thickening, heat transfer printing circuit, etching and cleaning on the ceramic plate, thereby preparing the pre-designed circuit board.
According to a preferred embodiment, the number of electrodes per square centimeter of the circuit board produced in step S1 is greater than or equal to 21.
According to a preferred embodiment, the electroplating thickening in step S1 is: copper thickness h of ceramic plate coating by electroplating 1 To 200 μm;
according to a preferred embodiment, step S2 comprises cutting the P-type and N-type ingots into wafers having a height of > 2mm, and electroplating the barrier layer Ni and the solder layer Sn; finally cutting the wafer into particles with preset sizes.
According to a preferred embodiment, step S2 further comprises polishing the wafer such that the wafer height difference is less than or equal to 0.02mm and the wafer height h 2 ≥2mm。
According to a preferred embodiment, step S3 comprises in particular:
the P-type and N-type material particles are alternately and uniformly placed in a tray at intervals, and the positions and the intervals of the particles are matched with those of the copper-clad circuit board;
printing 0.15mm solder on the steel screen, ensuring that the circuit board electrode is in anastomotic contact with each material particle, and then carrying out reflow soldering; and finally, insulating packaging is carried out at the edge of the device.
The foregoing inventive concepts and various further alternatives thereof may be freely combined to form multiple concepts, all of which are contemplated and claimed herein. Various combinations will be apparent to those skilled in the art from a review of the present disclosure, and are not intended to be exhaustive or all of the present disclosure.
The invention has the beneficial effects that:
the method increases the filling rate by increasing the particle density of the thermoelectric material, so that the thermoelectric generator prepared by the method has high performance due to the high filling rate, and smaller circuit current value and lower parasitic loss under the same condition are realized.
Under the environment of small temperature difference near room temperature, the thermoelectric generator prepared based on the method has the advantages of high output power, large open-circuit voltage, good mechanical property, low contact loss, low circuit loss and the like.
Drawings
Fig. 1 is a schematic diagram of a pi-type thermoelectric generator.
FIG. 2 is a graph of maximum output power of each fill-rate device as a function of fill-rate at different temperature differentials;
FIG. 3 is a graph of maximum output power of each fill-rate device as a function of temperature difference;
fig. 4 is a graph of 338 versus power density of the TEG at different temperature differentials versus other laboratory TEG, commercial TEG, and high performance TEG for high temperature applications.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
Example 1:
the embodiment discloses a method for improving output performance of a thermoelectric generator and relieving parasitic loss, which comprises the following steps:
(1) Preparation of copper-clad ceramic plate
The magnetron sputtering process is adopted to carry out the sputtering of 40 multiplied by 0.635mm 3 Depositing copper layer of 80nm on AlN ceramic plate, electroplating to thicken to 200 microns, thermal transfer printing, etching and other steps to prepare high density ceramic plate with copper electrodes over 21 in each square centimeter.
(2) Preparation of material particles
Bi of P type and N type 2 Te 3 Cutting the base ingot into piecesAfter grinding and polishing, electroplating a Ni barrier layer of 30 mu m and a Sn welding layer of 30 mu m, and then cutting the wafer into 0.9X0.9X2 mm 3 Is a particle of (2).
(3) Reflow soldering and insulating package
Printing a layer of solder paste with the thickness of 0.15mm on the electrode plate, welding the material particles (more than 42 particles per square centimeter) and the circuit board together in a tube furnace for 30min, and finally uniformly coating insulating glue on the edge of a welded finished product.
The method increases the filling rate by increasing the particle density of the thermoelectric material, so that the thermoelectric generator prepared by the method has high performance due to the high filling rate, and smaller circuit current value and lower parasitic loss under the same condition are realized.
Under the environment of small temperature difference near room temperature, the thermoelectric generator prepared based on the method has the advantages of high output power, large open-circuit voltage, good mechanical property, low contact loss, low circuit loss and the like.
Test case 1
This example prepares and discloses thermoelectric generators of 50 pairs (5% fill), 200 pairs (20% fill) and 338 pairs (34% fill), the three devices having the same material particle size. This embodiment aims to verify the effect of the filling rate on the output power. The method comprises the following specific steps:
step one: and (5) simulating and calculating. Finite element simulation is carried out on the three devices, and output power under ideal working conditions (without contact resistance and thermal resistance) is calculated, as shown by the dotted line part of fig. 2. The maximum output power of the three devices is linearly changed with the filling rate under different temperature differences.
Step two: and (5) experimental verification. Preparing a 1:1 experimental sample according to a simulation model, firstly cutting a bismuth telluride-based material into wafers with the height of 2mm, then electroplating nickel and tin, and finally cutting the wafers into wafers with the height of 0.9X0.9X2 mm 3 Is a particle of (2). According to the size of the particles and different filling rates, electrodes with the size of 5 multiplied by 1 multiplied by 0.2mm are respectively prepared 3 、3×1×0.2mm 3 2.5X1X0.2 mm 3 Is provided. And (5) performing reflow soldering and insulating packaging to finish the preparation. Through performance test, the variation of the output power with the filling rate under different temperature differences is shown as a broken straight line in fig. 2.
Step three: and (5) concluding. The output performance of the 338 pair (34% fill) device is best. Maximum output power at different temperature differences is 37mW, 333mW and 843mW respectively, which are greater than 50 pairs and 200 pairs of devices.
Test case 2
The present embodiment differs from test case 1 in that test case 1 is to verify that the high-density high-fill-rate device has high performance, and that test case 1 is to verify that the parasitic loss of the high-density high-fill-rate device is low. The method comprises the following specific steps:
step one: as in step one of test case 1, the maximum output power of the two devices under the working condition without contact resistance and contact thermal resistance is calculated in a simulation manner, as shown by the rectangular line part in fig. 3;
step two: as in step two of test case 1, the electrode size of the 50 pair (34% fill) device was 6X 2.4X 0.1mm 3 ；
Step three: parasitic losses are calculated. Wherein the parasitic loss of 338 devices at different temperature differences is the difference between the triangle with lines and the rectangle with lines in fig. 3. Similarly, the parasitic loss of 50 pairs of devices at different temperature differences is the difference between the to-be-rounded line and the rectangular line in fig. 3.
Step four: and (5) concluding. The ratios of 338 to device parasitic losses at different temperature differences were 39%, 46% and 51%, respectively, while the ratios of 50 to device parasitic losses at different temperature differences were 98%, 95% and 96%, respectively. The parasitic losses of 50 pairs of devices under different temperature differences are much higher than those of 338 pairs of devices.
Comparative example
Fig. 4 shows power density profiles for thermoelectric generators prepared using different methods at different temperature differentials. The devices prepared by adopting the electroplating deposition process in the cases of 127-Tcs (f=4%) and 71-Tcs (f=3%) have poor performance due to poor material performance, small effective temperature difference, low filling rate and the like; the 127-Tcs (f=18%) case adopts a preparation process similar to that of the invention, but the filling rate of the case is lower, so that the performance of the case is not obviously improved; 220-Tcs (f=38%) cases resulted in device output performance decay due to poor composite material performance. The 338 prepared by the method avoids adverse factors such as poor performance of a deposition material, small effective temperature difference of a micro device and the like for a device with high filling rate (f=34%) and integrates a micro preparation process and a processing technology of a block device, so that the filling rate is improved and meanwhile the contact heat loss is effectively relieved. The high performance of the 70-Tcs (f=31%) case is based on excellent material properties, while the commercial device case is based on good electrical and thermal contact.
In summary, optimizing material performance and improving electric and thermal contact have obvious effects on improving output performance of the thermoelectric generator, but the method capable of improving output performance and relieving electric energy loss provided by the invention has great potential in comparison with the method, and if the advantages of the two are integrated into the invention, namely, a high-performance thermoelectric material and an advanced electrode-material connection technology are adopted, the method has profound significance on development and popularization of the thermoelectric generator.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (7)
1. A method of improving thermoelectric generator output performance and mitigating parasitic losses, the method comprising the steps of:
s1: a preparation step of a copper-clad circuit board of a thermoelectric generator,
s2: a preparation step of P type/N type semiconductor material particles,
s3: and welding and packaging, namely alternately welding the P-type and N-type material particles on the copper-clad circuit board of the thermoelectric generator prepared in the step S1, and finishing insulating packaging of the edge of the circuit board.
2. The method of improving thermoelectric generator output performance and mitigating parasitic losses according to claim 1, wherein step S1 comprises:
and carrying out magnetic control copper coating, electroplating thickening, heat transfer printing circuit, etching and cleaning on the ceramic plate, thereby preparing the pre-designed circuit board.
3. The method of improving output performance and mitigating parasitic losses of a thermoelectric generator according to claim 1, wherein the number of electrodes per square centimeter of circuit board produced in step S1 is greater than or equal to 21.
4. The method of improving output performance and mitigating parasitic losses of a thermoelectric generator of claim 1, wherein the electroplating thickening in step S1 is: copper thickness h of ceramic plate coating by electroplating 1 To 200 μm.
5. The method of improving thermoelectric generator output performance and mitigating parasitic losses according to claim 1, wherein step S2 comprises dicing P-type and N-type base ingots into wafers having a height > 2mm, and electroplating barrier layer Ni and solder layer Sn; finally cutting the wafer into particles with preset sizes.
6. The method of improving thermoelectric generator output performance and mitigating parasitic losses according to claim 5, wherein step S2 further comprises polishing the wafer such that the wafer height difference is less than or equal to 0.02mm and the wafer height h is 2 ≥2mm。
7. The method of improving output performance and mitigating parasitic losses of a thermoelectric generator according to claim 1, wherein step S3 comprises:
the P-type and N-type material particles are alternately and uniformly placed in a tray at intervals, and the positions and the intervals of the particles are matched with those of the copper-clad circuit board;
printing 0.15mm solder on the steel screen, ensuring that the circuit board electrode is in anastomotic contact with each material particle, and then carrying out reflow soldering; and finally, insulating packaging is carried out at the edge of the device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310806407.2A CN116828954A (en) | 2023-06-30 | 2023-06-30 | Method for improving output performance of thermoelectric generator and relieving parasitic loss |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310806407.2A CN116828954A (en) | 2023-06-30 | 2023-06-30 | Method for improving output performance of thermoelectric generator and relieving parasitic loss |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116828954A true CN116828954A (en) | 2023-09-29 |
Family
ID=88127312
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310806407.2A Pending CN116828954A (en) | 2023-06-30 | 2023-06-30 | Method for improving output performance of thermoelectric generator and relieving parasitic loss |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116828954A (en) |
-
2023
- 2023-06-30 CN CN202310806407.2A patent/CN116828954A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10566514B2 (en) | Thermoelectric module | |
| JP6750404B2 (en) | Thermoelectric conversion module, thermoelectric conversion device, and method for manufacturing thermoelectric conversion module | |
| US8198116B2 (en) | Fabrication method for thermoelectric device | |
| US10217922B2 (en) | Methods for thick film thermoelectric device fabrication | |
| CN101401197B (en) | Electronic component module | |
| KR100310478B1 (en) | Thermoelectric piece and process of making the same | |
| US9252041B2 (en) | Electrostatic chuck | |
| US9300229B2 (en) | Electrostatic chuck | |
| CN103311262B (en) | Micro thermoelectric device, manufacture method and comprise its thermal generator | |
| KR20170076358A (en) | Thermoelectric module and method for fabricating the same | |
| CN105474418A (en) | Thermoelectric module, and heat conversion apparatus comprising same | |
| EP0827215A2 (en) | Thermoelectric modules and thermoelectric elements | |
| JPH0555640A (en) | Manufacture of thermoelectric converter and thermoelectric converter manufactured by the same | |
| JP6668645B2 (en) | Thermoelectric conversion module and method of manufacturing the same | |
| CN110178234A (en) | Electrothermal module | |
| CN203288656U (en) | A micro thermoelectric device | |
| CN107534077B (en) | Thermoelectric element, thermoelectric module, and heat conversion device including thermoelectric module | |
| CN116828954A (en) | Method for improving output performance of thermoelectric generator and relieving parasitic loss | |
| WO2017047627A1 (en) | Thermoelectric conversion module and thermoelectric conversion device | |
| JP5373225B2 (en) | Method for manufacturing thermoelectric conversion element module | |
| JP7314927B2 (en) | Thermoelectric conversion module member, thermoelectric conversion module, and method for manufacturing thermoelectric conversion module member | |
| KR20210090679A (en) | Thermal lensed electrode for thermoelectric generator with improved performance | |
| CA2868197C (en) | Methods for thick film thermoelectric device fabrication | |
| US3166449A (en) | Method of manufacturing semiconductor devices | |
| CN110429172A (en) | A kind of thermo-electric device and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |