Packaging method and application of optical window of light-storage integrated battery

Abstract

The invention discloses a packaging method and application of an optical window of a light-storage integrated battery. Comprising the following steps: processing an optical window in a central area of a battery anode shell by adopting a femtosecond laser system; cleaning the processed positive electrode shell by using absolute ethyl alcohol, and treating the cleaned positive electrode shell in plasma for later use; removing the front and back protective films of the flexible substrate, and identifying a conductive surface of the flexible substrate; uniformly coating epoxy resin slurry around the outer side of the optical window by using a piezoelectric microfluidic injection system to form an annular adhesive layer; under the guidance of red light, the conductive surface of the flexible substrate is aligned with the annular adhesive layer, vacuum adsorption is performed, and the annular adhesive layer is pre-cured; and re-curing the annular adhesive layer by using an ultraviolet LED to finish the packaging of the optical window of the light-storage integrated battery. The packaging method is suitable for various photoactive positive electrode materials such as V2O5, VO2, MoS2 and the like, and has universality.

Description

Technical Field

[0001] The present invention relates to the technical fields of materials science and electrochemistry, and particularly relates to a packaging method and application of an optical window for a photovoltaic and energy storage integrated battery. Background Art

[0002] With the development of photovoltaic and energy storage integrated technology, the packaging technology of the battery optical window has become a key factor determining the device performance. In traditional photovoltaic and energy storage batteries, holes are mainly drilled mechanically (such as a high-speed rotating drill bit) to create holes at specified positions on the positive electrode case of the battery for the installation of the optical window, etc. During the hole-opening process, if the hole diameter accuracy is insufficient or the burrs on the hole edge are not processed, it is easy to cause poor adaptability of the sealant, or cracks due to stress concentration during subsequent packaging, becoming a potential leakage hazard. For traditional optical window packaging, transparent glass, transparent plastic film and the battery shell are usually physically bonded on the surface with 502 glue. During the packaging process, the glue is prone to cracking due to the difference in the thermal expansion coefficients of the optical material and the shell material under temperature changes; if the mechanical seal has problems such as dimensional tolerance and improper installation, it is difficult to form an effective seal. In the prior art, there are two core problems in the optical window packaging technology.

[0003] Firstly, there is insufficient sealing performance and size adaptability: Traditional external packaging methods (such as external glue packaging) are prone to electrolyte leakage due to mechanical stress or material aging. Especially in micro-devices such as button batteries, the size mismatch between the window and the substrate (such as incomplete coverage or excessive occlusion of the substrate) will significantly reduce the light absorption efficiency and affect charge generation and transmission.

[0004] Secondly, there are defects in interface contact and universality: The contact interface between the optical window and the photoactive material lacks systematic optimization, resulting in uneven electron transport. Moreover, the existing processes are only designed for a single battery system and are difficult to adapt to the different requirements of different photoactive materials such as vanadium oxide and manganese oxide, and lithium / sodium / zinc ion batteries.

[0005] In the currently disclosed photovoltaic and energy storage integrated batteries, the geometric matching parameters between the window and the substrate are not clearly defined for the opening and packaging on the photoanode side, and the optimization of the sealing performance by the internal packaging structure is not involved. The work related to the welding structure of the button battery electrode assembly does not solve the problems of light transmission packaging and size design of the optical window. Therefore, there is an urgent need for a general packaging method based on precise size matching and internal packaging structure to improve the reliability and performance of the photovoltaic and energy storage integrated battery. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a packaging method and application of an optical window for a photovoltaic and energy storage integrated battery. By selecting the internal packaging structure and packaging materials, and precisely adapting the light transmission packaging of the optical window to the size, the present invention solves the problem of electrolyte leakage during battery packaging, effectively protects the internal components of the battery and allows them to fully contact the electrolyte, and improves the battery service life.

[0007] To achieve the above object, the technical solution designed by the present invention is as follows: The present invention provides a packaging method for an optical window of a photovoltaic and energy storage integrated battery, comprising the following steps: (1) Processing an optical window in the central region of the positive electrode case of the battery by using a femtosecond laser system; (2) Cleaning the positive electrode case in step (1) with absolute ethanol, and after cleaning, placing the positive electrode case in a plasma for treatment, and setting aside; (3) Removing the front and back protective films of the flexible substrate and identifying its conductive surface; (4) Using a piezoelectric microfluidic injection system to uniformly coat epoxy resin slurry around the outside of the optical window to form an annular adhesive layer; (5) Under the guidance of red light, aligning the conductive surface of the flexible substrate with the annular adhesive layer, vacuum adsorbing, and then pre-curing the annular adhesive layer; (6) Using an ultraviolet LED to re-cure the annular adhesive layer to complete the packaging of the optical window of the photovoltaic and energy storage integrated battery.

[0008] Further, in step (1), the specific parameters of the femtosecond laser system are: wavelength 750 - 850 nm, pulse width 45 - 55 fs, repetition frequency 0.5 - 1.5 kHz; The diameter of the optical window is 5 - 10 nm, and the surface roughness Ra of the edge of the optical window is ≤ 50 nm.

[0009] Still further, the specific parameters of the femtosecond laser system are: wavelength 800 nm, pulse width 50 fs, repetition frequency 1 kHz; The diameter of the optical window is 8 nm.

[0010] Still further, in step (2), the specific cleaning steps are: first performing 40 kHz ultrasonic waves for 5 - 6 min, and then simultaneously performing 40 kHz ultrasonic waves and 800 kHz megasonic waves for 25 - 30 min, and the power of the ultrasonic waves and the megasonic waves is 50% each; The plasma is argon, the plasma treatment power is 45 - 50 W, the air pressure is 10 - 12 Pa, and the time is 10 - 30 min.

[0011] Still further, in step (3), the flexible substrate is PET-ITO or PEN-ITO, the diameter of the flexible substrate is 7 - 12 mm, and the thickness is 0.2 - 0.5 mm.

[0012] Still further, the flexible substrate is PET-ITO, and the diameter of the flexible substrate is 10 mm.

[0013] Further, in the step (4), the epoxy resin slurry is a slurry containing 0.5% of nano-SiO2 modified epoxy resin; The thickness of the annular adhesive layer is 95 - 105 μm.

[0014] Further, in the step (5), 0 Pa < the pressure of vacuum adsorption < 10 Pa, the pre-curing temperature is 55 - 65 °C, and the pre-curing time is 4 - 6 min; In the step (6), the power of the UV LED is 6 - 10 W, the wavelength is 365 nm, and the re-curing time is 5 - 30 s.

[0015] The present invention also provides a positive electrode case with an optical window, and the optical window of the positive electrode case is encapsulated by the above-mentioned encapsulation method.

[0016] The present invention also provides an integrated photovoltaic and energy storage battery, and the integrated photovoltaic and energy storage battery includes the above-mentioned positive electrode case.

[0017] Principle of the present invention: 1. The present invention uses a femtosecond laser system to prepare an optical window on the positive electrode case, realizes non-thermal ablation through a multi-photon absorption mechanism, concentrates energy on the processing area, and avoids material melting and deformation caused by heat diffusion; and through an ultra-short pulse cold processing mechanism, realizes a non-thermally damaged microstructure with an edge roughness Ra ≤ 50 nm, ensures that the optical distortion of the window edge < 5%, and meets the high-precision light transmission requirements for in-situ optical characterization. The present invention uses a slurry containing 0.5% of nano-SiO2 modified epoxy resin. The nano-SiO2 modified epoxy resin improves the strength by increasing the interfacial anchoring effect, has a viscosity of 500 mPa•s to ensure uniform spreading of the adhesive layer, the annular structure provides sealing support, and the nano-filler enhances the mechanical properties.

[0018] 2. The present invention uses PET-ITO as a flexible substrate and selects PET-ITO / PEN-ITO materials as the holes of the open-cell battery case because they have material properties that match the requirements of photovoltaic and energy storage batteries (the light transmittance of PET and PEN reaches 88 - 92% and over 90% respectively, the sheet resistance of the ITO coating is as low as 10 Ω or less and is transparent and conductive, and the material has a flexibility with a bending radius of 1 mm or less at room temperature), process compatibility and stability (resistant to ethanol and argon plasma treatment, the Tg of PET and PEN are 70 °C and 100 °C respectively and can withstand the pre-curing temperature, the ITO coating can be deposited by processes such as magnetron sputtering and the substrate is easy to be processed into a diameter of 7 - 12 mm to match the size of the optical window), as well as cost and mass production advantages (as a mature flexible electronic material, the process is stable and the cost is lower than materials such as graphene).

[0019] 3. The diameter difference between the transparent flexible substrate and the optical window in the present invention is designed to be 2 mm, which is to meet the requirements of annular adhesive layer coating and encapsulation (when the diameter of the optical window is D, the diameter of the flexible substrate D + 2 mm can make the radial width of the annular adhesive layer reach 1 mm, ensuring that the adhesive layer has sufficient adhesive force and the ability to buffer mechanical stress, preventing electrolyte leakage and window rupture), ensuring alignment accuracy and optical path integrity (the 2 mm difference provides a tolerance margin for red light-guided alignment, avoiding incomplete coverage of the substrate or structural redundancy, and making the edge of the substrate exceed the edge of the window by 1 mm to ensure the optical signal transmission efficiency), and adapting to the encapsulation process parameters (under a vacuum adsorption pressure of 0 - 10 Pa and a pre-curing temperature of 55 - 65 °C, ensuring uniform adhesion of the substrate to the adhesive layer, and at the same time ensuring uniform light intensity and complete curing at the edge of the adhesive layer during ultraviolet curing).

[0020] Advantages of the present invention: 1. By optimizing the encapsulation method of the battery optical window, strictly selecting the material of the encapsulation substrate and controlling the usage amount of the encapsulation material, the present invention solves the problem of electrolyte leakage in the traditional battery optical window encapsulation, effectively protects the internal components of the battery from sufficient contact with the electrolyte, improves the battery service life, and greatly improves the convenience and electrochemical performance of the integrated photo-storage battery test. The present invention provides the possibility for the integration of battery cathode materials and other functional materials in a single unit, contributing to the development of multifunctional integrated photo-charging button batteries.

[0021] 2. Through the precise size matching (diameter difference of 2 mm) between the transparent flexible substrate and the optical window and the micro-quantification control of the epoxy resin usage amount (≤15 μL), the present invention constructs a geometric parameter optimization model for the photo-electric conversion interface, achieving a 40% improvement in the battery cycle stability while ensuring a light transmittance of more than 85%. Compared with the traditional encapsulation process, on the basis of maintaining the test convenience, the present invention creatively solves the key interface problem of the integrated photo-storage device, provides a standardized preparation scheme for in-situ spectroelectrochemical research, and constructs an innovative technical system of "precision machining of optical window - adaptation of flexible conductive substrate - optimization of interface energy encapsulation".

[0022] 3. The internally encapsulated V6O 13 -based integrated photo-storage battery assembled in the present invention exhibits excellent comprehensive performance under light: it achieves a light-assisted cycle life of more than 1400 times (capacity retention rate > 80%) at a current density of 1 A g -1 , which is more than 6 times higher than that of traditional vanadium-based materials; the light-assisted discharge specific capacity is as high as 468.7 mAh g -1 at 0.1 A g -1 , and at the same time, the light conversion efficiency is as high as 3.45%, significantly superior to the reported integrated photo-storage batteries of the same kind.

[0023] 4. Select V6O 13 The vanadium oxide-based positive electrode is used as the positive electrode of the integrated photovoltaic and energy storage battery. The integrated photovoltaic and energy storage battery assembled by the packaging method of the present invention exhibits reversible photo-charging cycle performance. The packaging method of the present invention is applicable to various photoactive semiconductor materials such as vanadium oxide and manganese oxide, and has universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a schematic structural diagram of an integrated photovoltaic and energy storage battery assembled with an inner encapsulation structure; In the figure, 1 is the optical window, 2 is the PET-ITO flexible substrate, 3 is the open positive electrode case, 4 is the positive electrode, 5 is the separator, 6 is the zinc foil, 7 is the gasket, 8 is the spring piece, and 9 is the negative electrode case; Figure 2 FIG. is a schematic diagram of the optical window of the integrated photovoltaic and energy storage battery; In the figure, the area outlined by the dotted line is the optical window; Figure 3 FIG. is a schematic diagram of the size of the optical window; In the figure, R is the radius of the positive electrode case, r is the radius of the optical window, d is the sealing width, and l is the conductive path width (l = R - r - d); Figure 4 FIG. is a result diagram of the optimal matching size of the optical window and the transparent flexible substrate of the integrated photovoltaic and energy storage battery; Figure 5 FIG. is for the integrated photovoltaic and energy storage battery assembled with an inner encapsulation structure at a scanning rate of 0.1 mV s -1 Comparison diagram of cyclic voltammograms; Figure 6 FIG. is the photo-assisted capacity diagram of the integrated photovoltaic and energy storage battery assembled with an inner encapsulation structure; Figure 7 FIG. is the rate performance diagram of the integrated photovoltaic and energy storage battery assembled with an inner encapsulation structure; Figure 8 FIG. is the photo-assisted cycle performance diagram of the integrated photovoltaic and energy storage battery assembled with an inner encapsulation structure and the integrated photovoltaic and energy storage battery with a traditional external package. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention will be further described in detail below in conjunction with specific embodiments for the understanding of those skilled in the art.

[0026] Example 1 The packaging method of the optical window of the integrated photovoltaic and energy storage battery specifically includes the following steps: 1. Using a femtosecond laser system with a wavelength of 800 nm and a pulse width of 50 fs (repetition frequency 1 kHz), a circular optical window with a diameter of 8 mm is processed in the central area of the positive electrode case of the CR2032 type battery (such as Figure 2as shown). The edge roughness Ra of the optical window is ≤ 50 nm.

[0027] 2. Place the processed positive electrode case from Step 1 into a polytetrafluoroethylene beaker, add 20 mL of absolute ethanol, and place the CR2032 positive electrode case (with the optical window facing up) on the polytetrafluoroethylene support in the beaker (to avoid direct contact with the cup wall), ensuring that the liquid level completely submerges the workpiece. Combine 40 kHz ultrasonic waves and 800 kHz megasonic waves for collaborative cleaning for a total of 30 min: First, turn on the 40 kHz ultrasonic waves for 5 min (power 80%) to mainly peel off the micron-sized metal debris (>5 μm) and large oil stain clusters remaining from laser processing, and then turn on the 40 kHz ultrasonic waves + 800 kHz megasonic waves simultaneously for 25 min (the power of the ultrasonic waves and megasonic waves is 50% each). The dual-frequency collaboration removes submicron-sized particles (0.1 - 5 μm) and medium-viscosity oil stains, and the ethanol dissolution effect is used to carry away the detached contaminants. Subsequently, transfer the cleaned positive electrode case to a plasma drying oven and treat it in 50 W argon plasma (atmospheric pressure 10 Pa) for 10 min.

[0028] 3. Prepare a PET-ITO wafer with a diameter of 10 mm (0.3 mm ≤ thickness ≤ 0.5 mm) as the flexible substrate. Inside an argon glove box, remove the front and back protective films through a film stripping device to avoid electrostatic contamination introduced by traditional manual operations, effectively reduce particle contamination on the substrate surface, and ensure the conductivity of the ITO layer and the cleanliness of subsequent processes.

[0029] 4. Use the four-probe method (probe spacing 1 mm) to conduct conductivity mapping on both sides of the PET-ITO flexible substrate to identify the conductive surface (the sheet resistance of the conductive surface < 20 Ω).

[0030] 5. Using a piezoelectric microfluidic injection system (droplet volume control accuracy ±2%), uniformly coat 5 μL of a slurry containing 0.5% nano-SiO2 modified epoxy resin (viscosity 500 mPa•s) around the outside of the optical window to form an annular adhesive layer with a thickness of 100 ± 5 μm (the optical transmittance of the adhesive layer > 90%, 15 MPa ≥ shear strength ≥ 12 MPa).

[0031] 6. Under the guidance of red light projected by a digital micromirror device (DMD) (positioning accuracy ±200 nm), the conductive surface of the PET-ITO flexible substrate is accurately aligned with the annular adhesive layer. The core role of the red light is to provide a visual alignment mark to ensure the precise alignment of the flexible substrate with the optical window. With its high-precision patterning, dynamic adjustment ability, and automation compatibility, DMD technology has become the most ideal red light projection solution in the optical storage battery packaging process. The interfacial gap between the flexible substrate and the positive electrode shell is eliminated through vacuum adsorption (0 Pa < pressure < 10 Pa), and the annular adhesive layer is pre-cured (60°C, 5 min) to achieve preliminary mechanical fixation. High-precision alignment ensures electrical connection and optical coaxiality, vacuum bonding eliminates bubbles, and pre-curing prevents displacement.

[0032] 7. Re-curing is carried out for 5 s using a 6 W UV-LED (main peak 365 nm) to initiate rapid cross-linking of the surface resin; internal deep curing is achieved using dielectric loss, increasing the shear strength of the packaging interface between the flexible substrate and the optical window to more than 8 MPa, and completing the packaging of the optical window of the integrated optical storage battery.

[0033] Example 2 A method for preparing an integrated optical storage battery specifically includes the following steps: 1. Using the packaging method of Example 1 to package the optical window of the open positive electrode shell, obtaining an open positive electrode shell with an optical window. As shown in the combination, a positive electrode, a separator, a zinc foil, a gasket, a spring piece, and a negative electrode shell are sequentially stacked on the open positive electrode shell with an optical window, electrolyte is added, and an integrated optical storage battery is assembled. In the integrated optical storage battery, V6O Figure 1 is selected as the positive electrode material, and the positive electrode material is drop-coated on a 17 mm 100-mesh titanium mesh. Zinc foil is selected as the negative electrode, and zinc trifluoromethanesulfonate is used as the electrolyte. 13

[0034] 2. After the battery is assembled, it is placed on a small hydraulic button battery sealing machine with the open positive electrode shell facing down. The pressure during battery packaging is 50 Mpa, and double closed-loop control is used to achieve high airtightness (leakage rate < 5×10 -10 mbar•L / s), obtaining an integrated optical storage battery.

[0035] For the optical window packaging of traditional optical storage batteries, usually, transparent optical glass or transparent plastic is fixed to the battery shell through glue bonding or mechanical seals. During the packaging process, the glue is prone to cracking due to the difference in the thermal expansion coefficients of the optical material and the shell material under temperature changes; if there are problems such as dimensional tolerances and improper installation of mechanical seals, it is difficult to form an effective seal, and there are significant differences in the installation position accuracy. The results are as Figure 8As shown, the method of welding the external package has a relatively serious risk of liquid leakage, which seriously affects the stability of the cycle test of the photovoltaic cell. The precise internal packaging of the present invention significantly improves the cycle stability and battery capacity of the photovoltaic cell.

[0036] The internally sealed optical window can better prevent the leakage of the electrolyte during battery packaging. When applying pressure for packaging, the transparent PET-ITO flexible substrate contacts the optical window more tightly, effectively protecting the internal components of the battery and ensuring sufficient contact with the electrolyte, thus improving the battery service life. The conductive side of the transparent PET-ITO flexible substrate faces the optical window, which helps to evenly distribute the current on the surface of the open positive electrode case during battery charging and discharging.

[0037] Example 3 Performance test of the integrated photovoltaic and energy storage battery in Example 2 1. Analyze the optimal matching dimensions of the optical window and the transparent flexible substrate of the integrated photovoltaic and energy storage battery. The results are as Figure 4 shown. Combining Figure 3 it can be seen that corresponding size adjustments should be made among the optical window, the transparent flexible substrate, and the amount of epoxy resin of the integrated photovoltaic and energy storage battery according to different battery models in order to fabricate a high-performance integrated photovoltaic and energy storage battery. r determines the charging efficiency of the integrated photovoltaic and energy storage battery, d determines the sealing performance and cycle life of the integrated photovoltaic and energy storage battery, and l determines the internal conductivity of the integrated photovoltaic and energy storage battery. In the integrated photovoltaic and energy storage battery, based on the radius R of the positive electrode case, the radius r of the optical window, the sealing width d, and the conductive path width l (l = R - r - d) need to be adaptively adjusted: the larger r is, the higher the light charging efficiency (due to the large light transmission area), but it will compress d (affecting the sealing performance and cycle life, and too small d is likely to cause electrolyte leakage and reduced life) and l (too small l will increase the internal resistance and poor conductivity); the three need to satisfy R > r + d. Small batteries balance light efficiency and sealing, high-power batteries prioritize ensuring l and reducing internal resistance, and long-life batteries increase d to strengthen sealing to achieve performance adaptation.

[0038] 2. Perform cyclic voltammetry analysis on the integrated photovoltaic and energy storage battery at a scanning rate of 0.1 mV s -1 . The results are as Figure 5 shown. The area of the cyclic voltammogram curve of the internally sealed integrated photovoltaic and energy storage battery under light is significantly higher than that in the dark state, indicating that light can effectively improve the battery capacity.

[0039] 3. Perform light-assisted capacity analysis on the integrated photovoltaic and energy storage battery. The results are as Figure 6 shown. The integrated photovoltaic and energy storage battery has a light-assisted discharge specific capacity as high as 468.7 mAh g -1 at a current density of 0.1 A g -1 . Compared with the discharge of a conventional zinc-ion battery, the capacity increase rate is close to 20%, which is at a relatively high level among the same type of batteries.

[0040] 4. Analyze the rate performance of the integrated photovoltaic and energy storage battery under light-assisted charging and conventional charging. The results are as Figure 7 shown. The light-assisted charging capacity is significantly higher than the conventional charging capacity, and the battery stability is good in both charging modes.

[0041] 5. Analyze the light-assisted cycling performance of the integrated photovoltaic and energy storage battery. The results are as Figure 8 shown. For the V6O-based integrated photovoltaic and energy storage battery (precision internal encapsulation) assembled internally at a current density of 1 A g -1 , compared with the conventional charging mode, light-assisted charging achieves a high capacity (340 - 380 mAh g 13 ), not only greatly improving the battery capacity, but also achieving a light-assisted cycle life of more than 1400 times (capacity retention rate > 90%). -1

[0042] Example 4 A method for encapsulating the optical window of an integrated photovoltaic and energy storage battery specifically includes the following steps: 1. Use a femtosecond laser system with a wavelength of 800 nm and a pulse width of 50 fs (repetition frequency 1 kHz) to process a circular optical window with a diameter of 5 mm in the central area of the positive electrode case of a CR2025-type battery (as Figure 2 shown). The surface roughness Ra of the edge of the optical window is ≤ 50 nm.

[0043] 2. Place the processed positive electrode case in step 1 into a polytetrafluoroethylene beaker, add 15 mL of absolute ethanol, and clean it according to the method in step 2 of Example 1. Then transfer it to a plasma drying oven and treat it in 50 W argon plasma (gas pressure 10 Pa) for 30 min.

[0044] 3. Prepare a PET-ITO flexible substrate wafer with a diameter of 7 mm (0.3 mm ≤ thickness ≤ 0.5 mm). Inside an argon glove box, remove the front and back protective films through a film stripping device to avoid electrostatic contamination introduced by traditional manual operations.

[0045] 4. Use the four-probe method (probe spacing 1 mm) to map the conductivity of both sides of the PET-ITO flexible substrate and identify the conductive surface.

[0046] 5. Use a piezoelectric microfluidic jetting system (liquid droplet volume control accuracy ±2%) to uniformly coat 5 μL of a slurry containing 0.5% nano-SiO2-modified epoxy resin (viscosity 500 mPa•s) around the outside of the optical window to form an annular adhesive layer with a thickness of 100 ± 5 μm (the optical transmittance of the adhesive layer > 90%, 15 MPa ≥ shear strength ≥ 12 MPa); 6. Under the guidance of the red light projected by the digital micromirror device (DMD) (positioning accuracy ±200 nm), the conductive surface of the PET-ITO flexible substrate is accurately aligned with the annular adhesive layer, and the interface gap between the flexible substrate and the positive electrode shell is eliminated by vacuum adsorption (0 Pa < pressure < 10 Pa), and the annular adhesive layer is pre-cured (60 °C, 10 min) to achieve preliminary mechanical fixation.

[0047] 7. Re-cure for 10 s using a 6 W UV-LED (main peak 365 nm) to initiate rapid cross-linking of the surface resin; utilize dielectric loss to achieve internal deep curing, increasing the shear strength of the encapsulation interface between the flexible substrate and the optical window to more than 8 MPa, and completing the encapsulation of the optical window of the integrated optical storage battery.

[0048] Example 5 A method for preparing an integrated optical storage battery specifically includes the following steps: 1. Use the encapsulation method of Example 4 to encapsulate the optical window of the open-hole positive electrode shell to obtain an open-hole positive electrode shell with an optical window, and stack the positive electrode, separator, zinc foil, gasket, shrapnel, and negative electrode shell on the open-hole positive electrode shell with an optical window in sequence as shown in Figure 1 . Add electrolyte to assemble the integrated optical storage battery. In the integrated optical storage battery, V6O 13 is selected as the positive electrode material, the positive electrode material is drop-coated on a 17 mm 100-mesh titanium mesh, zinc foil is selected as the negative electrode, and zinc trifluoromethanesulfonate is used as the electrolyte.

[0049] 2. After the battery assembly is completed, place it on a small hydraulic button battery sealing machine with the open-hole positive electrode shell facing down. The pressure during battery encapsulation is 45 Mpa, and high airtightness (leak rate < 5×10 -10 mbar•L / s) is achieved using double closed-loop control to obtain the integrated optical storage battery.

[0050] Taking the integrated optical storage battery assembled with internal encapsulation obtained in this example as an example, by placing the conductive surface of the transparent PET-ITO flexible substrate facing the optical window side and adjusting the size of r, the sealing performance of the interface between the photoactive positive electrode material and the open-hole positive electrode shell is improved, and the conductivity of the electrode material is enhanced. The integrated optical storage battery assembled with this internal encapsulation structure achieves reversible photo-assisted charge and discharge cycling under a light intensity of 70 mW / cm 2 , and the reversible capacity is 330 - 340 mAh / g.

[0051] Example 6 A method for encapsulating the optical window of an integrated optical storage battery specifically includes the following steps: 1. Use a femtosecond laser system with a wavelength of 800 nm and a pulse width of 50 fs (repetition rate 1 kHz) to process a circular optical window with a diameter of 10 mm in the central area of the positive electrode case of a CR2016 type battery (as Figure 2 shown). The edge roughness Ra of the optical window is ≤ 50 nm.

[0052] 2. Place the processed positive electrode case in step 1 into a polytetrafluoroethylene beaker, add 10 mL of absolute ethanol, and clean it according to the method in step 2 of Example 1. Then transfer it to a plasma drying oven and treat it in 50 W argon plasma (gas pressure 10 Pa) for 30 min.

[0053] 3. Prepare a PET-ITO flexible substrate wafer with a diameter of 12 mm (0.2 mm ≤ thickness ≤ 0.5 mm). Inside an argon glove box, remove the front and back protective films through a film stripping device to avoid electrostatic contamination introduced by traditional manual operations.

[0054] 4. Use the four-probe method (probe spacing 1 mm) to perform conductivity mapping on both sides of the PET-ITO flexible substrate to identify the conductive side (sheet resistance < 20 Ω); 5. Using a piezoelectric microfluidic jetting system (liquid droplet volume control accuracy ±2%), uniformly coat 15 μL of a slurry containing 0.5% nano-SiO₂ modified epoxy resin (viscosity 500 mPa•s) around the outside of the optical window to form an annular adhesive layer with a thickness of 100 ± 5 μm (the optical transmittance of the adhesive layer > 90%, 15 MPa ≥ shear strength ≥ 12 MPa).

[0055] 6. Under the guidance of the red light projected by a digital micromirror device (DMD) (positioning accuracy ±200 nm), accurately align the conductive side of the PET-ITO flexible substrate with the annular adhesive layer area, eliminate the interface gap between the flexible substrate and the positive electrode case through vacuum adsorption (0 Pa < pressure < 10 Pa), and perform pre-curing (60 °C, 10 min) on the annular adhesive layer to achieve preliminary mechanical fixation.

[0056] 7. Use 6 W UV-LED (main peak 365 nm) for re-curing for 20 s to initiate rapid cross-linking of the surface resin; utilize dielectric loss to achieve internal deep curing, and increase the shear strength of the encapsulation interface between the flexible substrate and the optical window to above 8 MPa to complete the encapsulation of the optical window of the integrated optical storage battery.

[0057] Example 7 A method for preparing an integrated optical storage battery, specifically including the following steps: 1. Use the encapsulation method of Example 6 to encapsulate an optical window for an open-hole positive electrode case to obtain an open-hole positive electrode case with an optical window, combined with Figure 1As shown, a positive electrode, a separator, a zinc foil, a gasket, a shrapnel, and a negative electrode case are stacked in sequence on the perforated positive electrode case with an optical window, and an electrolyte is added to assemble an integrated photovoltaic and energy storage battery. In the integrated photovoltaic and energy storage battery, V6O 13 is selected as the positive electrode material, and the positive electrode material is drop-coated on a 12 mm PET-ITO flexible substrate. Zinc foil is selected as the negative electrode, and zinc trifluoromethanesulfonate is used as the electrolyte.

[0058] 2. After the battery is assembled, it is placed on a small hydraulic button battery sealing machine with the perforated positive electrode case facing down. The pressure during battery encapsulation is 55 Mpa, and double closed-loop control is used to achieve high airtightness (leak rate < 5×10 -10 mbar•L / s) to obtain an integrated photovoltaic and energy storage battery.

[0059] Taking the integrated photovoltaic and energy storage battery assembled with internal encapsulation obtained in this embodiment as an example, the positive electrode material is directly drop-coated on a transparent PET-ITO flexible substrate without using a titanium mesh as a current collector, reducing the cost of battery assembly. By increasing the r size of the perforated positive electrode case and optimizing the d size, the airtightness of the battery is significantly improved, but the conductivity inside the battery is slightly reduced. The integrated photovoltaic and energy storage battery assembled with internal encapsulation realizes reversible light-assisted charge and discharge cycling under a light intensity of 70 mW / cm 2 with a reversible capacity of 280 - 300 mAh / g.

[0060] Example 8 A method for encapsulating an optical window of an integrated photovoltaic and energy storage battery specifically includes the following steps: 1. Using a femtosecond laser system with a wavelength of 750 nm and a pulse width of 45 fs (repetition frequency 0.5 kHz), a circular optical window with a diameter of 10 mm is processed in the central area of the positive electrode case of a CR2016 type battery (as Figure 2 shown). The surface roughness Ra of the edge of the optical window is ≤ 50 nm.

[0061] 2. Place the positive electrode case processed in step 1 in a polytetrafluoroethylene beaker, add 10 mL of absolute ethanol, and clean it according to the method in step 2 of Example 1. Subsequently, transfer it to a plasma drying oven and treat it in 45 W argon plasma (gas pressure 12 Pa) for 30 min.

[0062] 3. Prepare a PEN-ITO flexible substrate wafer with a diameter of 12 mm (0.2 mm ≤ thickness ≤ 0.5 mm). Inside an argon glove box, remove the front and back protective films through a film stripping device to avoid electrostatic contamination introduced by traditional manual operations.

[0063] 4. Use the four-probe method (probe spacing 1 mm) to perform conductivity mapping on both sides of the PEN-ITO flexible substrate to identify the conductive surface (sheet resistance < 20 Ω); 5. Using a piezoelectric microfluidic injection system (with a droplet volume control accuracy of ±2%), 15 μL of a slurry containing 0.5% nano-SiO₂ modified epoxy resin (viscosity 500 mPa•s) was evenly coated around the outer side of the optical window to form an annular adhesive layer with a thickness of 100 ± 5 μm (the optical transmittance of the adhesive layer > 90%, 15 MPa ≥ shear strength ≥ 12 MPa).

[0064] 6. Under the guidance of the red light projected by a digital micromirror device (DMD) (positioning accuracy ±200 nm), the conductive surface of the PEN-ITO flexible substrate was accurately aligned with the annular adhesive layer area. The interface gap between the flexible substrate and the positive electrode case was eliminated by vacuum adsorption (0 Pa < pressure < 10 Pa), and the annular adhesive layer was pre-cured (55°C, 10 min) to achieve preliminary mechanical fixation.

[0065] 7. Re-curing was carried out for 30 s using a 10 W UV-LED (main peak 365 nm) to initiate rapid cross-linking of the surface resin; internal deep curing was achieved by dielectric loss, increasing the shear strength of the encapsulation interface between the flexible substrate and the optical window to more than 8 MPa, and completing the encapsulation of the optical window of the integrated optical storage battery.

[0066] Example 9 A method for encapsulating an optical window of an integrated optical storage battery specifically includes the following steps: 1. Using a femtosecond laser system with a wavelength of 850 nm and a pulse width of 55 fs (repetition frequency 1.5 kHz), a circular optical window with a diameter of 10 mm was processed in the central area of the positive electrode case of the CR2016 type battery (as Figure 2 shown). The surface roughness Ra of the optical window ≤ 50 nm.

[0067] 2. The processed positive electrode case in step 1 was placed in a polytetrafluoroethylene beaker, 10 mL of absolute ethanol was added, and it was cleaned according to the method in step 2 of Example 1. Subsequently, it was transferred to a plasma drying oven and treated in 50 W argon plasma (gas pressure 10 Pa) for 30 min.

[0068] 3. Prepare a PEN-ITO flexible substrate wafer with a diameter of 12 mm (0.2 mm ≤ thickness ≤ 0.5 mm). Inside an argon glove box, the front and back protective films were removed through a film stripping device to avoid electrostatic contamination introduced by traditional manual operations.

[0069] 4. Conductivity mapping was performed on both sides of the PEN-ITO flexible substrate using the four-probe method (probe spacing 1 mm) to identify the conductive surface (sheet resistance < 20 Ω); 5. Using a piezoelectric microfluidic injection system (with a droplet volume control accuracy of ±2%), 15 μL of a slurry containing 0.5% nano-SiO2 modified epoxy resin (viscosity 500 mPa•s) is evenly coated around the outer side of the optical window to form an annular adhesive layer with a thickness of 100 ± 5 μm (the optical transmittance of the adhesive layer > 90%, 15 MPa ≥ shear strength ≥ 12 MPa).

[0070] 6. Under the guidance of the red light projected by a digital micromirror device (DMD) (positioning accuracy ±200 nm), the conductive surface of the PEN-ITO flexible substrate is accurately aligned with the annular adhesive layer area. The interface gap between the flexible substrate and the positive electrode shell is eliminated by vacuum adsorption (0 Pa < pressure < 10 Pa), and the annular adhesive layer is pre-cured (65°C, 10 min) to achieve preliminary mechanical fixation.

[0071] 7. Re-curing is carried out for 30 s using a 10 W UV-LED (main peak 365 nm) to initiate rapid cross-linking of the surface resin; internal deep curing is achieved by dielectric loss, increasing the shear strength of the encapsulation interface between the flexible substrate and the optical window to more than 8 MPa, and completing the encapsulation of the optical window of the integrated optical storage battery.

[0072] Other parts not described in detail are prior arts. Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, not all embodiments. People can also obtain other embodiments without creative efforts based on these embodiments, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A packaging method for the optical window of an integrated photovoltaic and energy storage battery, characterized in that: It includes the following steps: (1) Use a femtosecond laser system to process an optical window in the central region of the battery positive electrode case; (2) Clean the positive electrode case in step (1) with absolute ethanol. After cleaning, place the positive electrode case in a plasma for treatment and set it aside; (3) Remove the front and back protective films of the flexible substrate and identify its conductive surface; The flexible substrate is PET-ITO or PEN-ITO; (4) Use a piezoelectric microfluidic jetting system to evenly coat epoxy resin slurry around the outside of the optical window to form an annular adhesive layer; (5) Under the guidance of red light, align the conductive surface of the flexible substrate with the annular adhesive layer, perform vacuum adsorption, and then pre-cure the annular adhesive layer; (6) Use a UV LED to re-cure the annular adhesive layer to complete the encapsulation of the optical window of the integrated optical storage battery.

2. The encapsulation method according to claim 1, wherein: In step (1), the specific parameters of the femtosecond laser system are: wavelength 750 - 850 nm, pulse width 45 - 55 fs, repetition frequency 0.5 - 1.5 kHz; The diameter of the optical window is 5 - 10 nm, and the edge roughness Ra of the optical window ≤ 50 nm.

3. The encapsulation method according to claim 2, wherein: The specific parameters of the femtosecond laser system are: wavelength 800 nm, pulse width 50 fs, repetition frequency 1 kHz; The diameter of the optical window is 8 nm.

4. The encapsulation method according to claim 1, wherein: In step (2), the specific cleaning steps are: first perform ultrasonic waves at 40 kHz for 5 - 6 min, and then simultaneously perform ultrasonic waves at 40 kHz and megasonic waves at 800 kHz for 25 - 30 min, and the power of the ultrasonic waves and megasonic waves is each 50%; The plasma is argon, the plasma treatment power is 45 - 50 W, the air pressure is 10 - 12 Pa, and the time is 10 - 30 min.

5. The encapsulation method according to claim 1, characterized in that: In step (3), the diameter of the flexible substrate is 7 - 12 mm, and the thickness is 0.2 - 0.5 mm.

6. The encapsulation method according to claim 5, characterized in that: The flexible substrate is PET-ITO, and the diameter of the flexible substrate is 10 mm.

7. The encapsulation method according to claim 1, wherein: In step (4), the epoxy resin slurry is a slurry containing 0.5% of nano-SiO2 modified epoxy resin; The thickness of the annular adhesive layer is 95 - 105 μm.

8. The encapsulation method according to claim 1, wherein: In step (5), 0 Pa < the pressure of vacuum adsorption < 10 Pa, the pre-curing temperature is 55 - 65 °C, and the pre-curing time is 5 - 10 min; In step (6), the power of the UV LED is 6 - 10 W, the wavelength is 365 nm, and the re-curing time is 5 - 30 s.

9. A positive electrode case containing an optical window, characterized in that: The optical window of the positive electrode case is encapsulated by the encapsulation method described in claim 1.

10. A photovoltaic and energy storage integrated battery, characterized in that: The integrated optical storage battery includes the positive electrode case described in claim 9.

Images