An ultrafast charge processing method for improving the conductivity of slurry

Abstract

The application discloses an ultrafast charge processing method for improving the conductivity of slurry, which comprises the following steps: mixing metal particles, a binder, a solvent and an additive in a certain proportion to ensure that the metal particles are uniformly dispersed in the slurry; and discharging charges to the slurry after film formation to significantly improve the conductivity of the slurry film. The strong electric field and current generated by the charge discharge in the application can change the mutual contact of conductive particles in the film, thereby realizing different effects of regulating the conductive network and enabling the resistivity of the slurry film to be reduced from 1x10 6 Ω·cm to 1 Ω·cm.

Description

Technical Field

[0001] This invention relates to an electrical discharge machining (EDM) method, specifically to an ultrafast charge processing method that can enhance the conductivity of slurries, and belongs to the field of EDM technology. Background Technology

[0002] Conductive pastes have wide applications in high-tech fields such as solar cells, photovoltaic modules, and sensors. Their conductivity directly affects the performance of the end products. However, in practical applications, the conductivity of the paste is often limited by factors such as uneven distribution of conductive particles and poor contact between particles. Therefore, how to effectively improve the conductivity of conductive pastes has become an important research task.

[0003] Traditional methods for improving the conductivity of slurries include optimizing the material, shape, and size of conductive particles, improving slurry formulations, and employing special coating and sintering processes. However, these methods are mostly complex, costly, and have limited effectiveness, resulting in significant limitations in practical applications. Storing charge in a capacitor and then releasing it onto an object can generate an effect with ultrafast high voltage and high current. This effect, under the influence of current or voltage, can effectively control the microstructure of the material and improve the electrical contact between conductive particles. Simultaneously, it forms a conductive particle network within the slurry. Compared to traditional methods, charge discharge machining (CCM) technology not only significantly improves the conductivity of conductive slurries but also boasts a simple process, low cost, and broad application prospects.

[0004] Therefore, proposing a novel method for improving the conductivity of conductive pastes using ultrafast charge processing technology is not only of significant theoretical importance but also has immense practical application value. The realization of this technology is expected to promote the application and development of conductive pastes in sensors, solar cells, and electronic devices, improve the performance and reliability of related products, and drive technological innovation in materials science and engineering, thus possessing significant economic and social implications. In future development, this technology is expected to play a crucial role in more high-tech fields, providing strong support for scientific and technological progress and industrial development. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide an ultrafast charge processing method for improving the conductivity of slurry.

[0006] Technical solution: The present invention provides an ultrafast charge processing method for improving the conductivity of slurry, comprising the following steps:

[0007] (1) The conductive particles are uniformly mixed with solvent, binder and additives to obtain a mixed slurry;

[0008] (2) The mixed slurry is printed evenly on the substrate, dried and cured to form a conductive film on the substrate;

[0009] (3) Fix the substrate with the conductive film on the test stage, connect the charge generator to the conductive film, and set the discharge amount and discharge time as required.

[0010] (4) Trigger the charge generator to discharge charge on the conductive film, causing a change in its resistivity.

[0011] Furthermore, in step (1), the conductive particles are one or more of the following: metallic conductive particles or carbon material conductive particles.

[0012] Furthermore, the metallic conductive particles are silver, copper, aluminum, or nickel, while the carbon material conductive particles are carbon nanotubes, carbon black, or graphene.

[0013] Furthermore, in step (1), the particle size of the conductive particles is 1-10 μm.

[0014] Further, in step (1), the solvent is one or more of ethanol, isopropanol, butanone, DBE, terpineol, diethylene glycol butyl ether, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, ethylene glycol butyl ether acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether, ethyl acetate, and dichloromethane.

[0015] Further, in step (1), the adhesive is a slurry adhesive, which is one or more of polymer resin, inorganic glass powder, silicon material, such as epoxy resin EPON 828, EPON 1001F, acrylic resin, polyester resin, etc.

[0016] Further, in step (1), the additive is one or more of the following: polyvinylpyrrolidone, polyethylene glycol, hydroxypropyl methylcellulose, carbomer, silicone oil, polyether-modified silicone oil, sulfosuccinate, silica nanoparticles, alkylphenol polyoxyethylene ether, 2,6-di-tert-butyl-p-cresol, benzophenone, nano zinc oxide, silane coupling agent, titanate coupling agent, isocyanate curing agent, dicyandiamide, modified dicyandiamide, acid anhydride, boron trifluoride monoethylamine, amino resin, and sintering accelerator.

[0017] Furthermore, the silane coupling agent is γ-aminopropyltriethoxysilane or γ-aminopropyltrimethoxysilane.

[0018] Furthermore, the mass ratio of metallic conductive particles, solvent, binder and additive is 60-95:8-30:5-15:1-5; the mass ratio of carbon material conductive particles, solvent, binder and additive is 1-5:8-30:60-90:1-5.

[0019] Furthermore, in step (2), the substrate is a polytetrafluoroethylene board or a PVC board.

[0020] Furthermore, in step (2), the printing method is one of screen printing, inkjet printing, 3D printing, photovoltaic printing or transfer printing.

[0021] Furthermore, in step (2), the drying and curing temperature is 80-1000℃, preferably 100-500℃, and the drying and curing time is the time required for the slurry to be completely cured, generally 1-120 min, preferably 30 min.

[0022] Furthermore, in step (2), the thickness of the conductive film is 0.1 to 2 mm.

[0023] Furthermore, in step (3), the charge is applied directly to the conductive paste film.

[0024] Furthermore, in step (3), the discharge parameters are: discharge voltage 1 to 100 kV, and discharge time less than 10 μs.

[0025] Furthermore, in step (3), the high-voltage capacitor is charged with high voltage to form a charge generator, and the discharge time of the charge in the capacitor is controlled by a discharge relay.

[0026] Furthermore, in step (4), the change in resistivity is caused by the structural change of the contact network between conductive particles in the slurry.

[0027] Furthermore, in step (4), the adjustable resistivity range of the slurry is changed from 1×10⁻⁶. 6 The value drops from Ω·cm to 1Ω·cm.

[0028] Invention Principle: When a discharge voltage is applied to a conductive slurry, the conductive particles in the slurry vibrate, twist, rotate, or move due to Maxwell stress, causing changes in the structure of its conductive network. By adjusting factors such as the peak voltage and discharge time, the structure of the conductive network in the slurry can be controlled, thereby controlling the conductivity of the conductive slurry.

[0029] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0030] (1) The method of the present invention, through ultrafast charge processing, enables the conductive particles in the slurry to contact each other better, resulting in a significant decrease in the resistivity of the slurry. The range of adjustable slurry resistivity variation is basically from 1×10⁻⁶. 6 The value decreases from Ω·cm to 1 Ω·cm, with the optimal value reaching 2.5 × 10⁻⁶. 6 The Ω·cm decreased to 1.5Ω·cm.

[0031] (2) The method of the present invention makes the conductive particles inside the slurry more evenly distributed, thereby improving the quality of the final product.

[0032] (3) The method of the present invention is simple to operate and reduces production time and cost. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the embodiments.

[0034] Example 1

[0035] This invention discloses an ultrafast charge processing method for improving the conductivity of slurry, comprising the following steps:

[0036] (1) Mix 8.2g of silver powder (particle size of 5μm), 0.8g of isobutanol, 0.5g of epoxy resin EPON828 and 0.5g of γ-aminopropyltriethoxysilane uniformly in a mass ratio of 82:8:5:5 to obtain a mixed slurry;

[0037] (2) The mixed paste is evenly printed onto a 20cm×20cm PVC substrate using inkjet printing.

[0038] (3) The substrate printed with the mixed paste was dried and cured at 150°C for 30 min to form a 1 mm thick conductive film, and its initial resistivity was recorded (see Table 1).

[0039] (4) Fix the conductive film on the test bench, charge the high-voltage capacitor to form a charge generator, control the charge discharge time through a discharge relay, and connect the output terminal of the charge generator to the conductive film. Set the discharge voltage and time according to Table 1.

[0040] (5) Trigger the charge generator to discharge the conductive film, causing its resistivity to change. Record the final resistivity. The results are shown in Table 1.

[0041] Examples 2-4

[0042] The experimental procedure was the same as in Example 1, except that the mass ratio of silver, isobutanol, EPON 828 and γ-aminopropyltriethoxysilane was different. The basic steps were the same as in Example 1, and the specific parameters and results are shown in Table 1.

[0043] Table 1. Resistivity enhancement effects of different mass ratios of silver powder, isobutanol, EPON 828, and γ-aminopropyltriethoxysilane.

[0044]

[0045] As shown in Table 1, when the voltage is 100kV and the discharge time is 0.5μs, the resistivity of the conductive paste decreases significantly, reaching a maximum of 2.5×10⁻⁶. 6 The Ω·cm decreased to 1.1 Ω·cm.

[0046] Example 5

[0047] The experimental procedure is the same as in Example 1, except that the conductive particles are replaced with copper, the solvent with diethylene glycol butyl ether, the additive with isocyanate curing agent, and the discharge parameters are different. Specifically, it includes the following steps:

[0048] (1) Mix 6.5g of copper powder (particle size 5μm), 1.5g of diethylene glycol butyl ether, 1.5g of EPON 828 and 0.5g of isocyanate curing agent evenly in a mass ratio of 65:15:15:5 to obtain a mixed slurry;

[0049] (2) The mixed paste is evenly printed onto a 20cm×20cm PVC substrate using inkjet printing.

[0050] (3) The substrate printed with the mixed paste was dried and cured at 150°C for 30 minutes to form a 1 mm thick conductive film, and its initial resistivity was recorded (see Table 2).

[0051] (4) Fix the conductive film on the test bench, charge the high voltage capacitor to form a charge generator, control the charge discharge time through the discharge relay, connect the output terminal of the charge generator to the conductive film, set the discharge voltage and time, and set the corresponding parameters according to Table 2.

[0052] (5) Trigger the charge generator to discharge the conductive film, causing its resistivity to change. Record its final resistivity. The results are shown in Table 2.

[0053] Examples 6-8

[0054] The experimental procedure was the same as in Example 5, except that the mass ratio of copper powder, diethylene glycol butyl ether, EPON 828 and isocyanate was different. The basic steps were the same as in Example 5, and the specific parameters are shown in Table 2. The results are shown in Table 2.

[0055] Table 2. Resistivity reduction effect of different mass ratios of copper powder, diethylene glycol butyl ether, EPON 828, and isocyanate curing agent.

[0056]

[0057] As shown in Table 2, when the voltage is 80 kV and the discharge time is 1 μs, the resistivity of the conductive slurry decreases significantly, reaching a maximum of 3.2 × 10⁻⁶. 7 The Ω·cm decreased to 4.2 Ω·cm.

[0058] Example 9

[0059] The experimental procedure is the same as in Example 1, except that the solvent is changed to diethylene glycol butyl ether, the binder is changed to acrylic resin, the additive is changed to polyvinylpyrrolidone, and the discharge parameters are different. Specifically, it includes the following steps:

[0060] (1) Mix 7g of silver powder (particle size of 5μm), 1g of diethylene glycol butyl ether, 1.5g of acrylic resin and 5g of polyvinylpyrrolidone evenly in a mass ratio of 70:10:15:5 to obtain a mixed slurry;

[0061] (2) The mixed paste is evenly printed onto a 20cm×20cm PVC substrate using inkjet printing.

[0062] (3) The substrate printed with the mixed paste was dried and cured at 120°C for 30 min to form a 1 mm thick conductive film, and its initial resistivity was recorded (see Table 3).

[0063] (4) Fix the conductive film on the test bench, charge the high voltage capacitor to form a charge generator, control the charge discharge time through the discharge relay, connect the output terminal of the charge generator to the conductive film, set the discharge voltage and time, and set the corresponding parameters according to Table 3.

[0064] (5) Trigger the charge generator to discharge the conductive film, causing its resistivity to change. Record its final resistivity. The results are shown in Table 3.

[0065] Examples 10-12

[0066] The experimental procedure was the same as in Example 9, except that the mass ratio of silver, diethylene glycol butyl ether, acrylic resin and polyvinylpyrrolidone was different. The basic steps were the same as in Example 9, and the specific parameters are shown in Table 3. The results are shown in Table 3.

[0067] Table 3. Resistivity reduction effects of different mass ratios of silver powder, diethylene glycol butyl ether, acrylic resin, and polyvinylpyrrolidone.

[0068]

[0069] As shown in Table 3, when the voltage is 50 kV and the discharge time is 0.5 μs, the resistivity of the conductive paste decreases significantly, reaching a maximum of 2.7 × 10⁻⁶. 8 The Ω·cm decreased to 11.9 Ω·cm.

[0070] Example 13

[0071] The experimental procedure is the same as in Example 1, except that the conductive particles are replaced with carbon nanotubes, the solvent with terpineol, the binder with low-melting-point glass powder, and the amounts and discharge parameters are different. Specifically, it includes the following steps:

[0072] (1) Mix 0.5g carbon nanotubes, 2.5g terpineol, 6.5g low melting point glass powder and 0.5g γ-aminopropyltriethoxysilane evenly in a mass ratio of 5:25:65:5;

[0073] (2) The mixed paste is evenly printed onto a 20cm×20cm PVC substrate using inkjet printing.

[0074] (3) The substrate printed with the mixed paste was dried and cured at 180°C for 30 minutes to form a 1 mm thick conductive film, and its initial resistivity was recorded (see Table 4).

[0075] (4) Fix the conductive film on the test bench, charge the high voltage capacitor to form a charge generator, control the charge discharge time through the discharge relay, connect the output terminal of the charge generator to the conductive film, set the discharge voltage and time, and set the corresponding parameters according to Table 4.

[0076] (5) Trigger the charge generator to discharge the conductive film, causing its resistivity to change. Record its final resistivity. The results are shown in Table 4.

[0077] Examples 14-16

[0078] The experimental procedure was the same as in Example 13, except that the mass ratio of carbon nanotubes, terpineol, low-melting-point glass powder and γ-aminopropyltriethoxysilane was different. The basic steps were the same as in Example 13. The specific parameters are shown in Table 4, and the results are shown in Table 4.

[0079] Table 4. Resistivity reduction effects of carbon nanotubes, terpineol, low-melting-point glass powder, and γ-aminopropyltriethoxysilane at different mass ratios.

[0080]

[0081] As shown in Table 4, when the voltage is 5kV and the discharge time is 1μs, the resistivity of the conductive paste decreases significantly, reaching a maximum of 1.7×10⁻⁶. 7 The Ω·cm decreased to 25.6 Ω·cm.

[0082] Comparative Examples 1-4

[0083] The experimental procedure was the same as in Examples 1-4, except that the voltage was different. Specific parameters and results are shown in Table 5.

[0084] Table 5. Resistivity reduction effect of different mass ratios of silver powder, isobutanol, EPON 828, and γ-aminopropyltriethoxysilane.

[0085]

[0086] As shown in Table 5, when the voltage is 0.5 kV and the discharge time is 0.5 μs, the resistivity of the conductive paste only decreases slightly, with an overall decrease of approximately 1 × 10⁻⁶. 6 Ω·cm decreased to 10 5 The range of Ω·cm. The effect of changing the resistivity is far less than that of Examples 1-4. This indicates that voltage is an important factor affecting the conductivity of the slurry.

[0087] Comparative Examples 5-8

[0088] The experimental procedure was the same as in Examples 5-8, except that the discharge time was different. Specific parameters and results are shown in Table 6.

[0089] Table 6. Resistivity reduction effect of different mass ratios of copper powder, diethylene glycol butyl ether, EPON 828, and isocyanate curing agent.

[0090]

[0091] As shown in Table 6, when the voltage is 80 kV and the discharge time is 20 μs, the resistivity of the conductive slurry decreases slightly, approximately from 1 × 10⁻⁶. 9 Ω·cm decreased to 10 6 The range of Ω·cm. The effect of changing resistivity is much smaller than in Examples 5-8, indicating that discharge time is an important factor affecting the conductivity of the slurry.

[0092] Comparative Examples 9-12

[0093] The experimental procedure was the same as in Examples 9-12, except that the mass ratio of silver powder: diethylene glycol butyl ether: acrylic resin: polyvinylpyrrolidone was different. The specific parameters and results are shown in Table 7.

[0094] Table 7. Resistivity reduction effects of different mass ratios of silver powder, diethylene glycol butyl ether, acrylic resin, and polyvinylpyrrolidone.

[0095]

[0096] As shown in Table 7, at a voltage of 50 kV and a discharge time of 0.5 μs, the resistivity of the conductive slurry decreases slightly, approximately from 1 × 10⁻⁶. 9 Ω·cm decreased to 10 7 The range of Ω·cm. The effect of changing resistivity is much smaller than that in Examples 9-12, indicating that the mass ratio of silver powder: diethylene glycol butyl ether: acrylic resin: polyvinylpyrrolidone is an important factor affecting the conductivity of the slurry.

[0097] Comparative Examples 13-16

[0098] The experimental procedure was the same as in Examples 13-16, except that the mass ratio of carbon nanotubes: terpineol: low melting point glass powder: γ-aminopropyltriethoxysilane was different. The specific parameters and results are shown in Table 8.

[0099] Table 8. Resistivity reduction effects of carbon nanotubes, terpineol, low-melting-point glass powder, and γ-aminopropyltriethoxysilane at different mass ratios.

[0100]

[0101] As shown in Table 8, when the voltage is 5kV and the discharge time is 0.1μs, the resistivity of the conductive slurry decreases slightly, approximately from 1×10⁻⁶. 8 Ω·cm decreased to 10 7 The range of Ω·cm. The effect of changing resistivity is much smaller than that of Examples 13-16, indicating that the mass ratio of carbon nanotubes: terpineol: low melting point glass powder: γ-aminopropyltriethoxysilane is an important factor affecting the conductivity of the slurry.

[0102] In summary, the experiments show that the raw material mass ratio, voltage, and discharge time all affect the improvement of the slurry conductivity in the method of this invention. Ultimately, it was found that the optimal mass ratio of metallic conductive particles, solvent, binder, and additives is 60–95:8–30:5–15:1–5; and the optimal mass ratio of carbon-based conductive particles, solvent, binder, and additives is 1–5:8–30:60–90:1–5. Under conditions of a voltage of 1–100 kV and a discharge time of less than 10 μs, the slurry conductivity can be approximately increased from 1 × 10⁻⁶ kV to 100 kV. 6 The value decreases from Ω·cm to 1Ω·cm.

Claims

1. An ultrafast charge processing method for improving the conductivity of slurry, characterized in that, Includes the following steps: (1) The conductive particles are uniformly mixed with solvent, binder and additive to obtain a mixed slurry; the conductive particles are one or more of metal conductive particles or carbon material conductive particles, and the mass ratio of metal conductive particles, solvent, binder and additive is 60~95:8~30:5~15:1~5; the mass ratio of carbon material conductive particles, solvent, binder and additive is 1~5:8~30:60~90:1~5; (2) The mixed paste is evenly printed on the substrate, dried and cured to form a conductive film on the substrate; The drying and curing temperature is 80~1000℃ o C, drying and curing time: 1~120 min; (3) Fix the substrate with conductive film on the test stage, connect the output end of the charge generator to the conductive film, and set the discharge amount and discharge time according to the requirements; apply the charge directly to the conductive film, and the discharge parameters are: discharge voltage 1~100 kV, discharge time less than 10 μs; (4) Trigger the charge generator to discharge the conductive film, causing a change in its resistivity.

2. The ultrafast charge processing method for improving the conductivity of slurry according to claim 1, characterized in that, The conductive metallic particles are silver, copper, aluminum, or nickel, while the conductive carbon materials are carbon nanotubes, carbon black, or graphene.

3. The ultrafast charge processing method for improving the conductivity of slurry according to claim 1, characterized in that, In step (1), the adhesive is one or more of the following: polymer resin, inorganic glass powder, silicon material, etc.

4. The ultrafast charge processing method for improving the conductivity of slurry according to claim 1, characterized in that, In step (1), the additive is one or more of the following: polyvinylpyrrolidone, polyethylene glycol, hydroxypropyl methylcellulose, carbomer, silicone oil, polyether-modified silicone oil, sulfosuccinate, silica nanoparticles, alkylphenol polyoxyethylene ether, 2,6-di-tert-butyl-p-cresol, benzophenone, nano zinc oxide, silane coupling agent, titanate coupling agent, isocyanate curing agent, dicyandiamide, modified dicyandiamide, acid anhydride, boron trifluoride monoethylamine, amino resin, and sintering accelerator.

5. The ultrafast charge processing method for improving the conductivity of slurry according to claim 1, characterized in that, In step (2), the printing method is one of screen printing, inkjet printing, 3D printing, photovoltaic printing or transfer printing.

6. The ultrafast charge processing method for improving the conductivity of slurry according to claim 1, characterized in that, In step (2), the thickness of the conductive film is 0.1~2 mm.

7. The ultrafast charge processing method for improving the conductivity of slurry according to claim 1, characterized in that, In step (4), the change in resistivity is caused by the structural change of the contact network between conductive particles in the slurry, and the resistivity of the slurry can be adjusted from 1×10 6 The value drops from Ω·cm to 1 Ω·cm.

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