Photovoltaic electrode with separable substrate, and preparation method therefor

Abstract

A photovoltaic electrode with a separable substrate, and a preparation method therefor, relating to the technical field of photovoltaic electrodes. The photovoltaic electrode with the separable substrate comprises a substrate (10), separable ink (20) formed on the surface of the substrate (10), and a wire on the surface of the ink (20). The ink (20) is formed on the substrate (10) in a separable manner, so that when the wire needs to be used, the substrate (10) can be stripped from the wire, and the problem of reduction of an photoelectric conversion effect caused by yellowing of the substrate (10) is avoided.

Description

Photovoltaic electrode with detachable carrier and preparation method thereof Technical Field

[0001] The present application relates to the field of photovoltaic electrodes, and in particular to a photovoltaic electrode having a detachable carrier in which a conductor is directly formed on a carrier by electroplating, and the carrier is detachable from the conductor, and a method for preparing the photovoltaic electrode having a detachable carrier. Background Art

[0002] The primary purpose of photovoltaic electrodes is to collect the current generated by the cell after photoelectric conversion and transmit it to the outside world via a similar soldering ribbon or output device. Previously, numerous applicants and publications have described techniques for separating photovoltaic electrodes from the cell surface. In other words, rather than fabricating the electrodes on the cell surface, the electrodes are fabricated away from the cell and then bonded to the cell surface.

[0003] Judging from the various currently available information, many different photovoltaic electrodes have been continuously developed like mushrooms after rain. These photovoltaic electrodes, which are different in structure and process, have one thing in common: they all have a carrier, and on the carrier, there are copper wires embedded in the carrier as conductors.

[0004] First, let's consider the copper wires that serve as conductors. Since copper wires are typically round, after being bonded to the battery and then covered with adhesive film, a laminator uses high heat and pressure to secure the film to the battery's surface, protecting the electrodes. However, it's a well-known fact that during the lamination process, the encapsulating film melts. During this time, the conductors atop the molten film are likely to shift, twist, deform, and undergo various other unexpected behaviors. When these conditions occur, the electrodes within the component naturally cease to function as intended.

[0005] Next, we'll discuss the carrier used to support the wires after the electrodes are removed from one side of the battery. Because hot-melt adhesives easily melt, the most popular carrier currently available is PET: polyethylene terephthalate (PET), the most common type of thermoplastic polyester. Also known as polyester resin, PET or PEIT (hereinafter referred to as PET) is a condensation polymer of terephthalic acid and ethylene glycol. It offers the following advantages:

[0006] 1. It has good mechanical properties, the impact strength is 3 to 5 times that of other films, and it has good folding resistance.

[0007] 2. Resistant to oil, fat, dilute acid, dilute alkali and most solvents.

[0008] 3. Pure PET has low heat resistance, with a heat deformation temperature of only about 85°C. However, this can be significantly increased after reinforcement treatment. The heat deformation temperature of reinforced PET can reach 225°C. PET also has good heat aging resistance, with a brittle temperature of -70°C and a certain toughness at -30°C. PET is also non-flammable.

[0009] 4. The permeability of gas and water vapor is low, and it has excellent gas, water, oil and odor resistance.

[0010] 5. High transparency, can block ultraviolet rays, and has good gloss.

[0011] 6. Non-toxic, odorless, hygienic and safe, can be used directly for food packaging.

[0012] From the advantages described above, it's clear that PET possesses numerous advantages. Coupled with its enhanced deformation temperature, which can reach 225°C, it appears to be an excellent choice as a carrier for electrode conductors. However, since photovoltaic cells rely primarily on the photoelectric conversion effect to generate current, illumination is crucial for photovoltaic cells. However, the reality is that when PET is used as an electrode carrier for a period of time, it will experience degradation due to the generation of free radicals by its chain polymers in high temperatures, oxidizing environments, exposure to ultraviolet and infrared radiation, and the effects of microorganisms. This can cause molecular chain breakage and lead to appearance changes such as yellowing and brittleness. Once PET, as a carrier, ages, it blocks natural light from reaching the cell, reducing the photoelectric effect.

[0013] Summary of the Invention

[0014] The present invention has developed a carrier that can be peeled off from the conductor during use, thereby avoiding the effect of reduced photoelectric conversion effect caused by aging of the carrier.

[0015] In a first aspect, the present invention provides a photovoltaic electrode with a detachable carrier, comprising:

[0016] a carrier;

[0017] Ink, the ink is formed on a free surface of the carrier in a patterned and detachable manner; and

[0018] A plurality of conductive lines corresponding to the ink and firmly formed on one side of the ink are arranged in parallel with each other, wherein each conductive line has at least one straight line segment on its cross-sectional outer contour, so that the conductive line can be peeled off from the carrier in a detachable manner.

[0019] In a preferred embodiment, the ink is a UV viscosity-reducing ink.

[0020] In a preferred embodiment, the carrier is a release film.

[0021] In a preferred embodiment, each of the conductive wires comprises an upper structure and a lower structure which is integrally formed with the upper structure and is asymmetrical in shape.

[0022] In a preferred embodiment: the height of the conductive line is not less than 50% of its width; and it also includes one or more auxiliary lines formed on one side of the carrier, the auxiliary lines are connected to the conductive line and are electrically connected to support the conductive line.

[0023] In a preferred embodiment, the height of the auxiliary line is at least half of the height of the conductive line.

[0024] In a preferred embodiment, a protective layer covering the conductive wire is further included to prevent the conductive wire from being oxidized.

[0025] In a preferred embodiment, a protective layer is further included to respectively cover the conductive wires and the auxiliary wires to prevent the conductive wires and the auxiliary wires from being oxidized.

[0026] In a preferred embodiment, the thickest of the wires does not exceed 100 microns.

[0027] In a preferred embodiment, the auxiliary line and the conducting wire intersect at an angle of 45 to 90 degrees.

[0028] In a preferred embodiment, the distance between two adjacent intersections of the auxiliary line and the conductive line is no more than 5 mm.

[0029] In a second aspect, the present invention provides a method for preparing a photovoltaic electrode having a detachable carrier, comprising the steps of:

[0030] preparing a carrier;

[0031] Printing patterned ink on the surface of the carrier in a detachable manner;

[0032] forming a conductive line seed layer on the patterned ink;

[0033] forming a conductive line layer on the conductive line seed layer, wherein the conductive line layer comprises a plurality of conductive lines, and each conductive line has at least one straight line segment on a cross-sectional outer contour; and

[0034] The vector is selectively removed to prevent deletions caused by aging of the vector.

[0035] In a preferred embodiment, the carrier is PET.

[0036] In a preferred embodiment, the conductive line seed layer is formed by activating the ink layer with a laser.

[0037] In a preferred embodiment, the conductor layer is formed by first performing chemical plating on the conductor seed layer and then electroplating the conductor.

[0038] In a preferred embodiment, the conductive line layer comprises an upper structure and a lower structure which is integrally formed with the upper structure and is asymmetrical in shape.

[0039] In a preferred embodiment, the method further comprises forming a protective layer having conductivity on the conductive wire layer and covering the conductive wire layer to prevent oxidation of the conductive wire layer and enhance adhesion.

[0040] In a preferred embodiment, the protective layer is selected from tin-bismuth alloy or tin-bismuth alloy containing glass powder.

[0041] The present invention securely combines the carrier, ink, and conductors, pre-positioning and securing the conductors to achieve a regular arrangement. This prevents significant displacement during production, transportation, and use. Furthermore, by depositing the ink on the carrier in a removable manner, the carrier can be peeled off from the conductors when needed, eliminating the problem of reduced photoelectric conversion efficiency due to yellowing of the carrier.

[0042] The detailed description of the present invention and its embodiments will be illustrated in the following detailed description in conjunction with the following drawings, and will not be limited thereto. The described parts are merely examples of the present invention and have no direct impact on the scope of the present invention. Therefore, the following description should not be interpreted in a limiting manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a cross-sectional plan view of a carrier in the structure of the present invention.

[0044] FIG2 is a cross-sectional plan view of the structure of the present invention with ink added to the carrier.

[0045] FIG3 is a cross-sectional plan view of a conductive line seed layer formed on a carrier by ink in the structure of the present invention.

[0046] FIG4 is a cross-sectional plan view of a conductive line and a second conductive line formed on a carrier through a conductive line seed layer in the structure of the present invention.

[0047] FIG5 is a cross-sectional plan view of the structure of the present invention after the carrier is separated from the mesh structure formed by the conductive wires and the second conductive wires.

[0048] FIG6 is a process flow chart of the present invention for preparing a photovoltaic electrode with a detachable carrier.

[0049] FIG. 7 is another process flow chart of the present invention for preparing a photovoltaic electrode with a detachable carrier. DETAILED DESCRIPTION

[0050] Various embodiments of the present invention are directed to providing a photovoltaic electrode with a detachable carrier and a method for preparing the same.

[0051] Please refer to Figures 1 to 5, which show the photovoltaic electrode of the detachable carrier provided by the present invention, including: a carrier 10; ink 20, which is formed on a free surface of the carrier 10 in a patterned manner and in a detachable manner; and a plurality of wires corresponding to the ink 20 and firmly formed on one side of the ink 20, arranged parallel to each other, wherein each wire has at least one straight line segment on its cross-sectional outer contour, so that the ink 20 can be peeled off from the carrier 10 in a detachable manner.

[0052] Specifically, please refer to FIG. 6 , in which the process for preparing a photovoltaic electrode with a detachable carrier provided by the present invention can be seen.

[0053] First, a carrier 10 is prepared. This carrier 10 is preferably a rigid plastic sheet, such as PET. Then, a patterned ink 20 is formed on one side of the carrier 10 using existing, commercially available techniques, such as screen printing. It is worth noting that the carrier 10 can also be a rigid plastic adhesive with a release function (i.e., a release film). In another embodiment, a layer of UV-resistant adhesive can be applied to the surface of the carrier 10, which is then bonded to the carrier 10, while the patterned ink 20 is printed on the surface of the UV-resistant adhesive. Alternatively, the ink 20 itself is a UV viscosity-reducing ink. Specifically, the adhesion of the ink 20 is modulated by a viscosity-reducing agent, which is also called a spreading agent. The dosage is generally 3-5% of the ink. Some waxes are added to the ink body, or some waxes and greases are added to vaseline as the main body. These viscosity-reducing agents mostly use refined bleached linseed oil and high-boiling point kerosene as the main body, and are added with synthetic resins, gelling agents and waxes to make them into a semi-gel state for use. This viscosity-reducing agent is used for glossy inks and resin inks, which can not only reduce the viscosity but also maintain the original ink's fixing speed, gloss and other ink properties.

[0054] The ink 20 is then activated, for example, by a laser, to form a conductive seed layer 30 on the surface of the ink 20. It should be noted that the ink 20 is formed in a mesh-like pattern during printing, so the conductive seed layer 30 is also formed in a mesh-like pattern on the surface of the carrier 10. A conductive layer 40 is then formed on the surface of the conductive seed layer 30 by chemical plating. The conductive layer 40 comprises a plurality of conductive lines, each of which has at least one straight line segment in its cross-sectional profile. The carrier 10 can then be removed from the conductive layer 40 as needed. The removal method can be determined based on the aforementioned embodiments. For example, if a release-capable carrier 10 is used, the conductive layer 40 can be directly separated from the surface of the carrier 10. If a UV-sensitive adhesive or similar adhesive is applied to the surface of the carrier 10, the conductive layer 40 can be irradiated with ultraviolet light (UV) to weaken the adhesive's adhesion to the carrier 10, allowing the carrier 10 to be removed. Alternatively, if the ink 20 itself is a UV-resistant, viscosity-reducing ink, then after the conductor layer 40 is completed, it can be irradiated with ultraviolet light (UV) to weaken or even eliminate the ink 20's adhesion to the carrier 10, thereby allowing the conductor to be separated from one side of the carrier 10. Either method can perfectly separate the carrier 10 from the conductor, resulting in the structure 50 shown in FIG5 . This prevents the adverse effects of carrier 10 aging on the photoelectric conversion effect when the conductor is attached to the side of the battery (not shown).

[0055] It is noteworthy that, as shown in FIG4 , when the conductor layer 40 is formed on the conductor seed layer 30 by the electrolyte in the electrolytic cell, each conductor has an upper structure 412 and a lower structure 411 that is integrally formed with the upper structure 412 and asymmetrical in shape. The lower structure 411 shown can be a thin layer of chemical copper layer formed by chemical electroplating or other conductive base layer for electroplating. Then, by reduction in the electrolyte, a layer of electroplated copper with a geometric shape or any conductive metal suitable for electroplating reduction can be formed on one side of the lower structure 411, and an upper structure 412 is formed on one side of the lower structure 411 in subsequent electroplating. As can be seen from the figure, the upper structure 412 is a trapezoid or any shape other than a circle or an ellipse. The main purpose of making the upper structure 412 and the lower structure 411 that is asymmetrical in shape with respect to the upper structure 412 is to prevent the conductor from twisting, slipping, deforming or displacing.

[0056] Furthermore, in order to facilitate the support of the wires, the wire layer 40 also includes one or more auxiliary wires 42. At the same time as the wires are formed, several auxiliary wires 42 can be formed on the surface of the wire seed layer 30 (the formation method is the same as the formation method of the wires). The auxiliary wires 42 intersect with each group of the wires in the range of 45 degrees to 90 degrees, preferably 90 degrees (vertical intersection). Since the auxiliary wires 42 and the wires can intersect at an angle from 45 degrees to a right angle (90 degrees), in order to efficiently play a supporting role, it is preferred that the distance between the two adjacent intersections between the auxiliary wires 42 and each group of wires is not greater than 5 millimeters (5mm). The purpose of providing the auxiliary wires 42 is to support the wires to prevent the wires from collapsing, displacing or twisting during the lamination process. For example, if a conductor has a width of 50 microns (μm) and a height of 70 microns (μm), without the support provided by the auxiliary wires 42, the conductor is likely to collapse during the lamination process. In short, when the conductor's aspect ratio is greater than or equal to 1, it is best to provide auxiliary wires 42 to support the conductor. Furthermore, the height (h) of the auxiliary wires 42 is preferably at least half of the height (H) of the conductor, or more, to achieve the desired support height. Preferably, the conductor's height is no less than 50% of its width. Furthermore, the thickest conductor should not exceed 100 microns (μm), and the width of the auxiliary wires 42 should not exceed 200 microns (μm).

[0057] Furthermore, as shown in FIG7 , to prevent oxidation of the conductive layer 40 (including the conductive wires and auxiliary wires 42) by oxygen in the air after formation, a conductive protective layer 43 can be formed on the outside of the conductive layer 40, either before removing the carrier 10 or after the conductive layer 40 is formed. The protective layer can be a tin-bismuth alloy, or a tin-bismuth alloy containing glass frit. This is because the thermal expansion coefficients of the copper conductive wires and the oxides on the silicon chip battery do not match, making them susceptible to separation after a period of use. Therefore, the glass frit added to the protective layer on the outside of the conductive layer 40 can align their thermal expansion coefficients, thereby resolving the problem of separation between the electrode sheet and the battery.

[0058] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the description is to be regarded as illustrative rather than restrictive.

Claims

1. A photovoltaic electrode with a detachable carrier, characterized in that: include: A carrier; Ink, the ink is formed on a free surface of the carrier in a patterned manner and in a detachable manner; as well as A plurality of conductive lines corresponding to the ink and firmly formed on one side of the ink are arranged in parallel with each other, wherein each conductive line has at least one straight line segment on its cross-sectional outer contour, so that the ink can be detached from the carrier.

2. The photovoltaic electrode with a detachable carrier as claimed in claim 1, characterized in that: The ink is a UV viscosity-reducing ink.

3. The photovoltaic electrode with a detachable carrier as claimed in claim 1, characterized in that: The carrier is a release film.

4. The photovoltaic electrode with a detachable carrier as claimed in claim 1, characterized in that: Each of the wires has an upper structure and a lower structure which is formed integrally with the upper structure and is asymmetrical in shape.

5. The photovoltaic electrode with a detachable carrier according to claim 1 or 4, characterized in that: The height of the conductor is not less than 50% of its width; and It also includes one or more auxiliary lines formed on one side of the carrier, and the auxiliary lines are connected to the conductive lines and are electrically connected to support the conductive lines.

6. The photovoltaic electrode with a detachable carrier as claimed in claim 5, characterized in that: The height of the auxiliary line is at least half of the height of the conductive line.

7. The photovoltaic electrode with a detachable carrier as claimed in claim 1, characterized in that: The invention also comprises a protective layer covering the wire to prevent the wire from being oxidized.

8. The photovoltaic electrode with a detachable carrier as claimed in claim 5, characterized in that: It also includes protective layers that respectively cover the conductive wires and the auxiliary wires to prevent the conductive wires and the auxiliary wires from being oxidized.

9. The photovoltaic electrode with a detachable carrier as claimed in claim 1, characterized in that: The thickest of the wires is no more than 100 microns.

10. The photovoltaic electrode with a detachable carrier as claimed in claim 5, characterized in that: The auxiliary line and the conductive line intersect at an angle of 45 to 90 degrees.

11. The photovoltaic electrode with a detachable carrier as claimed in claim 5, characterized in that: The distance between two adjacent intersection points of the auxiliary line and the conductive line is no greater than 5 mm.

12. A method for preparing a photovoltaic electrode with a detachable carrier, characterized in that: Includes steps: preparing a carrier; Printing patterned ink on the surface of the carrier in a detachable manner; forming a conductive line seed layer on the patterned ink; forming a conductive line layer on the conductive line seed layer, wherein the conductive line layer has a plurality of conductive lines, and each conductive line has at least one straight line segment on a cross-sectional outer contour; and The vector is selectively removed to avoid loss of the vector after aging.

13. The method for preparing a photovoltaic electrode with a detachable carrier according to claim 12, characterized in that: The carrier is PET.

14. The method for preparing a photovoltaic electrode with a detachable carrier according to claim 12, characterized in that: The conductive line seed layer is formed by activating the ink layer with a laser.

15. The method for preparing a photovoltaic electrode with a detachable carrier according to claim 12 or 14, characterized in that: The conductor layer is formed by first performing chemical plating on the conductor seed layer and then electroplating the conductor.

16. The method for preparing a photovoltaic electrode with a detachable carrier according to claim 12, characterized in that: The conductor layer comprises an upper structure and a lower structure which is formed integrally with the upper structure and is asymmetrical in shape.

17. The method for preparing a photovoltaic electrode with a detachable carrier according to claim 12 is characterized in that: The method further includes forming a protective layer having conductivity on the wire layer and covering the wire layer to prevent oxidation of the wire layer and enhance adhesion.

18. The method for preparing a photovoltaic electrode with a detachable carrier according to claim 17, characterized in that: The protective layer is selected from tin-bismuth alloy or tin-bismuth alloy containing glass powder.

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