Three-dimensional shapable thermoelectric device based on silk-screen printing and preparation method of three-dimensional shapable thermoelectric device

Abstract

The invention belongs to the technical field of new energy devices, and particularly provides a three-dimensional shapable thermoelectric device based on silk-screen printing and a preparation method thereof, and the three-dimensional shapable thermoelectric device is prepared through multiple times of printing on a TPU substrate by using a multi-layer silk-screen printing process. A temperature gradient can be established along a heat flow direction between a human body and an environment, so that a temperature difference between a cold end and a hot end is collected under the driving of a vertical heat flow and is converted into an output voltage, and meanwhile, the device has very considerable self-repairing capability and flexibility; moreover, based on the low-cost characteristic and customizable characteristic of the silk-screen printing technology, the three-dimensional shapable thermoelectric device is expected to drive low-power-consumption electronic products to play an important role in the field of wearable energy supply.

Description

Technical Field

[0001] This invention belongs to the field of new energy device technology, specifically providing a structure and preparation method of a three-dimensional shapeable thermoelectric device based on screen printing. Background Technology

[0002] Since the concept of the Internet of Things (IoT) was first proposed in 1999, the market size of IoT has continued to expand at an unprecedented rate, playing an increasingly important role in people's daily lives. As the number of IoT nodes continues to grow, their energy consumption is also rising rapidly, necessitating the development of new energy sources to power these nodes. In recent years, although power generation technologies such as wind power, hydropower, and solar power have continued to develop, not all power supply methods can meet the complex needs of IoT scenarios. At the same time, the maintenance costs of IoT devices are high, regular battery replacements result in significant waste, and environmental pollution is also a concern. Furthermore, there is a large amount of energy wasted in daily life, requiring the collection and conversion of this energy into electricity. Considering all these factors, thermoelectric energy harvesting technology stands out among various power generation methods due to its reliability.

[0003] Based on this, the present invention provides a wearable thermoelectric device and its preparation method, specifically a three-dimensional shapeable thermoelectric device based on screen printing and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a three-dimensional shapeable thermoelectric device based on screen printing and its fabrication method. Utilizing a multi-layer screen printing process, a three-dimensional shapeable thermoelectric device is fabricated on a TPU substrate through multiple printing processes. This allows the device to establish a temperature gradient along the heat flow direction between the human body and the environment, thereby collecting the temperature difference between the hot and cold ends under vertical heat flow and converting it into an output voltage. Simultaneously, the device possesses considerable self-healing capabilities and flexibility. Furthermore, based on the low-cost and customizable characteristics of screen printing, this three-dimensional shapeable thermoelectric device is expected to play a significant role in driving low-power electronic products in the field of wearable power supply.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A three-dimensional shapeable thermoelectric device based on screen printing, characterized in that the three-dimensional shapeable thermoelectric device is composed of several thermoelectric units connected in series, each thermoelectric unit adopting a multi-layer printed structure, including: a bottom silver electrode layer, a P-type thermoelectric material layer, a silver electrode conductor layer, a PDMS insulating layer, an upper silver electrode layer, and a top heat-absorbing PDMS layer, wherein:

[0007] The bottom silver electrode layer is printed on the TPU substrate with conductive silver paste;

[0008] The P-type thermoelectric material layer is printed on the bottom silver electrode layer by P-type thermoelectric ink, and the silver electrode conductor layer is printed on another bottom silver electrode layer by conductive silver paste. In the same thermoelectric unit, the P-type thermoelectric material layer and the silver electrode conductor layer are respectively disposed on two bottom silver electrode layers, and adjacent thermoelectric units are connected in series through the bottom silver electrode layers.

[0009] The PDMS insulating layer is printed with PDMS ink on the TPU substrate, covering the TPU substrate and the bottom silver electrode layer, and filling the space between the P-type thermoelectric material layer and the silver electrode conductor layer.

[0010] The upper silver electrode layer is printed with conductive silver paste on the P-type thermoelectric material layer and the silver electrode conductor layer in the same thermoelectric unit;

[0011] The top heat-absorbing PDMS layer is printed with PDMS heat-absorbing ink on the PDMS insulating layer, covering the PDMS insulating layer and the upper silver electrode layer.

[0012] Furthermore, the P-type thermoelectric ink is composed of PEDOT, polyvinyl alcohol (PVA), and perfluorosulfonic acid (Nafion), with a mass ratio of PEDOT:PVA:Nafion = 1:1.15:0.125.

[0013] Furthermore, the PDMS ink is composed of PDMS precursor and curing agent, with a mass ratio of PDMS precursor to curing agent of 7.5:1 to 5:1.

[0014] Furthermore, the PDMS heat-absorbing ink is composed of PDMS ink and carbon black, with carbon black accounting for 5-10 wt% of the PDMS ink.

[0015] Furthermore, several thermoelectric units are arranged in a serpentine pattern.

[0016] Furthermore, both the P-type thermoelectric material layer and the silver electrode conductor layer adopt a cylindrical structure and have the same thickness.

[0017] Furthermore, the multi-layered printed structure is positioned by alignment marks during the printing process, and after each printing is completed, it is placed in an oven for curing.

[0018] Furthermore, the method for fabricating the three-dimensional shapeable thermoelectric device based on screen printing is characterized by comprising the following steps:

[0019] Step 1: Add dimethyl sulfoxide (DMSO) solution to PEDOT:PSS solution and stir evenly at room temperature to form P-type thermoelectric material base liquid;

[0020] Step 2: Add polyvinyl alcohol (PVA) powder and perfluorosulfonic acid (Nafion) solution to the base liquid at a mass ratio of PEDOT:PVA:Nafion = 1:1.15:0.125, and stir evenly at 85°C to form P-type thermoelectric material ink.

[0021] Step 3: Print conductive silver paste onto the TPU substrate and cure it to form the underlying silver electrode;

[0022] Step 4: Print the P-type thermoelectric material ink and conductive silver paste onto the bottom silver electrode in steps. After each printing, cure it. Multiple printings will form the P-type thermoelectric material layer and the silver electrode conductor layer, both of which have the same thickness.

[0023] Step 5: Mix the PDMS prepolymer and curing agent in the specified ratio, and stir evenly at room temperature to form PDMS ink;

[0024] Step 6: Print PDMS ink onto the TPU substrate, cure to form a PDMS insulating layer, cover the bottom silver electrode and fill the space between the P-type thermoelectric legs and the silver electrode conductor layer;

[0025] Step 8: Print conductive silver paste onto the P-type thermoelectric material layer and the silver electrode conductor layer, and cure to form the upper silver electrode layer;

[0026] Step 9: Add carbon black to the PDMS ink and stir evenly at room temperature to form PDMS heat-absorbing ink;

[0027] Step 10: Print the PDMS heat-absorbing ink onto the PDMS insulating layer, covering the PDMS insulating layer and the upper silver electrode layer; then cure to form the top heat-absorbing PDMS layer.

[0028] Furthermore, the curing conditions for the conductive silver paste are: baking in an oven at 80–90°C for 15 minutes.

[0029] Furthermore, the curing conditions for the P-type thermoelectric material ink are: baking in an oven at 70-80°C for 30 minutes and then standing at room temperature for 6 hours.

[0030] Furthermore, the curing conditions for PDMS ink are the same as those for PDMS heat-absorbing ink, specifically: baking in an oven at 60–80°C for 2 hours.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] This invention proposes a structure for a three-dimensional shapeable thermoelectric device based on screen printing, which can collect heat in the vertical direction and has a compact structure that is easy to integrate. More importantly, the device is prepared by screen printing, which has the characteristics of low cost and easy mass production. Furthermore, the three-dimensional shapeable thermoelectric device based on screen printing in this invention has a multi-layer printed structure, and each layer of the printed structure uses a flexible self-healing material, which can be applied in a variety of occasions and has considerable self-healing ability and flexibility. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the three-dimensional shapeable thermoelectric device based on screen printing in this invention.

[0034] Figure 2 This is a schematic diagram of the generation mechanism of the three-dimensional shapeable thermoelectric device based on screen printing in this invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0036] Example 1

[0037] This embodiment proposes a three-dimensional shapeable thermoelectric device based on screen printing, with the structure as follows: Figure 1 As shown, the three-dimensional shapeable thermoelectric device is fabricated through multiple screen printing processes, resulting in a multi-layered printed structure. The three-dimensional shapeable thermoelectric device consists of several thermoelectric units connected in series. Each thermoelectric unit includes: a bottom silver electrode layer, a P-type thermoelectric material layer, a silver electrode conductor layer, a PDMS insulating layer, an upper silver electrode layer, and a top heat-absorbing PDMS layer, wherein:

[0038] The substrate material for the screen printing process is a TPU film with dimensions of 40mm × 30mm and a thickness of 0.5mm; the bottom silver electrode layer is printed on the TPU substrate with conductive silver paste.

[0039] The P-type thermoelectric material layer is printed with P-type thermoelectric ink on the bottom silver electrode layer, serving as a P-type thermoelectric leg and outputting voltage under the influence of the temperature gradient at its hot and cold ends. The silver electrode conductor layer is printed with conductive silver paste on another bottom silver electrode layer. In the same thermoelectric unit, the P-type thermoelectric material layer and the silver electrode conductor layer are respectively disposed on two bottom silver electrode layers. Adjacent thermoelectric units are connected in series through the bottom silver electrode layers, and several thermoelectric units are arranged in a serpentine pattern. Both the P-type thermoelectric material layer and the silver electrode conductor layer adopt a cylindrical structure with a diameter of 5mm.

[0040] The PDMS insulating layer is printed with PDMS ink on the TPU substrate, covering the TPU substrate and the bottom silver electrode layer, and filling the space between the P-type thermoelectric material layer and the silver electrode conductor layer.

[0041] The upper silver electrode layer is printed with conductive silver paste on the P-type thermoelectric material layer and the silver electrode conductor layer in the same thermoelectric unit, providing a channel for carrier flow.

[0042] The top heat-absorbing PDMS layer is printed with PDMS heat-absorbing ink on the PDMS insulating layer, covering the PDMS insulating layer and the upper silver electrode layer;

[0043] The multi-layer printed structure is positioned by alignment marks during the printing process, and the sample is placed in an oven for curing after each printing.

[0044] like Figure 2 As shown, when there is a temperature difference between the two ends (hot end and cold end), the three-dimensional shapeable thermoelectric device relies on the Seebeck effect of PEDOT material to make P-type charge carriers move in a specific direction to form a voltage and provide a potential difference between the two ends; at the same time, the top PDMS heat absorption layer can also continuously provide heat to the top, serving as a heat source to provide a temperature difference.

[0045] Meanwhile, this embodiment provides a method for fabricating the above-mentioned three-dimensional shapeable thermoelectric device based on screen printing, specifically including the following steps:

[0046] Step 1: Add dimethyl sulfoxide (DMSO) solution to PEDOT:PSS solution at a ratio of 5 vol% and stir at room temperature for 30 min to prepare the base liquid for P-type thermoelectric material.

[0047] Step 2: Add polyvinyl alcohol (PVA) powder and perfluorosulfonic acid (Nafion) solution to the base solution at a mass ratio of PEDOT:PVA:Nafion = 1:1.15:0.125, and stir at 85°C for 5 hours to obtain P-type thermoelectric material ink. It should be noted that during the weighing process of PEDOT:PVA:Nafion = 1:1.15:0.125, PEDOT and Nafion are calculated according to the mass of solutes in the corresponding solutions.

[0048] Step 3: Print conductive silver paste onto the TPU substrate and bake it in an oven at 85°C for 15 minutes to solidify and form the bottom silver electrode.

[0049] Step 4: Print the P-type thermoelectric material ink and conductive silver paste onto the underlying silver electrode in stages, and repeat the printing process multiple times to achieve a certain thickness (approximately 50 μm). After each printing, the P-type thermoelectric material is baked in an oven at 70–80°C for 30 minutes and then left to stand at room temperature for 6 hours. After each printing, the conductive silver paste is baked in an oven at 80–90°C for 15 minutes. This process ultimately forms the P-type thermoelectric legs and the silver electrode conductor layer, both of which have the same thickness.

[0050] Step 5: Mix the PDMS prepolymer with the curing agent (hydroxyl-terminated polydimethylsiloxane: polyethylene silicate) at a mass ratio of 7.5:1 to 5:1 and stir for 5 minutes to obtain the PDMS ink.

[0051] Step 6: Print PDMS ink onto the TPU substrate to form a PDMS insulating layer, cover the bottom silver electrode and fill the space between the P-type thermoelectric legs and the silver electrode conductor layer; then bake in an oven at 60-80℃ for 2 hours to complete the curing.

[0052] Step 8: Print the conductive silver paste onto the top layer of Step 7, and bake it in an oven at 80-90°C for 15 minutes to solidify and form the upper silver electrode.

[0053] Step 9: The ratio of PDMS prepolymer to curing agent is 7.5:1. Stir for 5 minutes, add 5wt% carbon black and stir evenly to make PDMS heat-absorbing ink.

[0054] Step 10: Print the PDMS heat-absorbing ink onto the PDMS insulating layer, covering the PDMS insulating layer and the upper silver electrode layer; then bake in an oven at 60-80℃ for 2 hours to cure and form the top heat-absorbing PDMS layer.

[0055] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A three-dimensional shapeable thermoelectric device based on screen printing, characterized in that, The three-dimensional shapeable thermoelectric device is composed of several thermoelectric units connected in series. Each thermoelectric unit adopts a multi-layer printed structure, including: a bottom silver electrode layer, a P-type thermoelectric material layer, a silver electrode conductor layer, a PDMS insulating layer, an upper silver electrode layer, and a top heat-absorbing PDMS layer, wherein: The bottom silver electrode layer is printed on the TPU substrate with conductive silver paste; The P-type thermoelectric material layer is printed on the bottom silver electrode layer by P-type thermoelectric ink, and the silver electrode conductor layer is printed on another bottom silver electrode layer by conductive silver paste. In the same thermoelectric unit, the P-type thermoelectric material layer and the silver electrode conductor layer are respectively disposed on two bottom silver electrode layers, and adjacent thermoelectric units are connected in series through the bottom silver electrode layers. The PDMS insulating layer is printed with PDMS ink on the TPU substrate, covering the TPU substrate and the bottom silver electrode layer, and filling the space between the P-type thermoelectric material layer and the silver electrode conductor layer. The upper silver electrode layer is printed with conductive silver paste on the P-type thermoelectric material layer and the silver electrode conductor layer in the same thermoelectric unit; The top heat-absorbing PDMS layer is printed with PDMS heat-absorbing ink on the PDMS insulating layer, covering the PDMS insulating layer and the upper silver electrode layer.

2. The three-dimensional shapeable thermoelectric device based on screen printing according to claim 1, characterized in that, P-type thermoelectric ink is composed of PEDOT, polyvinyl alcohol (PVA), and perfluorosulfonic acid (Nafion), with a mass ratio of PEDOT:PVA:Nafion = 1:1.15:0.

125.

3. The three-dimensional shapeable thermoelectric device based on screen printing according to claim 1, characterized in that, PDMS ink is composed of PDMS precursor and curing agent, with a mass ratio of PDMS precursor to curing agent of 7.5:1 to 5:1; PDMS heat-absorbing ink is composed of PDMS ink and carbon black, with carbon black accounting for 5 to 10 wt% of the mass of PDMS ink.

4. The three-dimensional shapeable thermoelectric device based on screen printing according to claim 1, characterized in that, Several thermoelectric units are arranged in a serpentine pattern.

5. The three-dimensional shapeable thermoelectric device based on screen printing according to claim 1, characterized in that, Both the P-type thermoelectric material layer and the silver electrode conductor layer adopt a cylindrical structure and have the same thickness.

6. The three-dimensional shapeable thermoelectric device based on screen printing according to claim 1, characterized in that, The multi-layer printed structure is positioned by alignment marks during the printing process, and after each printing is completed, it is placed in an oven for curing.

7. The method for fabricating a three-dimensional shapeable thermoelectric device based on screen printing according to claim 1, characterized in that, Includes the following steps: Step 1: Add dimethyl sulfoxide (DMSO) solution to PEDOT:PSS solution and stir evenly at room temperature to form P-type thermoelectric material base liquid; Step 2: Add polyvinyl alcohol (PVA) powder and perfluorosulfonic acid (Nafion) solution to the base liquid at a mass ratio of PEDOT:PVA:Nafion = 1:1.15:0.125, and stir evenly at 85°C to form P-type thermoelectric material ink. Step 3: Print conductive silver paste onto the TPU substrate and cure it to form the underlying silver electrode; Step 4: Print the P-type thermoelectric material ink and conductive silver paste onto the bottom silver electrode in steps. After each printing, cure it. Multiple printings will form the P-type thermoelectric material layer and the silver electrode conductor layer, both of which have the same thickness. Step 5: Mix the PDMS prepolymer and curing agent in the specified ratio and stir evenly at room temperature to form PDMS ink; Step 6: Print PDMS ink onto the TPU substrate, cure to form a PDMS insulating layer, cover the bottom silver electrode and fill the space between the P-type thermoelectric legs and the silver electrode conductor layer; Step 8: Print conductive silver paste onto the P-type thermoelectric material layer and the silver electrode conductor layer, and cure to form the upper silver electrode layer; Step 9: Add carbon black to the PDMS ink and stir evenly at room temperature to form PDMS heat-absorbing ink; Step 10: Print the PDMS heat-absorbing ink onto the PDMS insulating layer, covering the PDMS insulating layer and the upper silver electrode layer; then cure to form the top heat-absorbing PDMS layer.

8. The method for fabricating a three-dimensional shapeable thermoelectric device based on screen printing according to claim 7, characterized in that, The curing conditions for the conductive silver paste are: baking in an oven at 80-90℃ for 15 minutes.

9. The method for fabricating a three-dimensional shapeable thermoelectric device based on screen printing according to claim 7, characterized in that, The curing conditions for P-type thermoelectric material ink are: baking in an oven at 80-90℃ for 30 minutes and then letting it stand at room temperature for 6 hours.

10. The method for fabricating a three-dimensional shapeable thermoelectric device based on screen printing according to claim 7, characterized in that, The curing conditions for PDMS ink and PDMS heat-absorbing ink are the same, specifically: baking in an oven at 60-80°C for 2 hours.

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