Solar silicon wafer connecting structure and photovoltaic module
By using copper strips and conductive adhesive at the silicon wafer splice seams, combined with a nano-silver wire resin layer or grid structure, the problems of low power generation efficiency and high cost caused by solder strips are solved, achieving efficient and low-cost solar silicon wafer connection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MING CROWN ADVANCED MATERIAL CO LTD
- Filing Date
- 2022-11-10
- Publication Date
- 2026-07-03
Smart Images
Figure CN115621349B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photovoltaic cell technology, and in particular to a solar silicon wafer connection structure and a photovoltaic module. Background Technology
[0002] When using solder ribbons as current collectors for solar silicon wafers, the ribbon material is primarily tin. The drawbacks of solder ribbons are twofold: first, their width obscures a significant portion of the silicon wafer surface, reducing the effective power generation area and thus impacting power generation efficiency; second, the primary material of the solder ribbon is tin, which has an electrical conductivity of 9.17 × 10⁻⁶. 6 S / m, compared to the conductivity of copper (59.6 × 10⁻⁶). 6 The solder ribbon has several drawbacks: firstly, it has high resistance and significant internal energy loss; secondly, the individual silicon wafers using solder ribbon have a large area, making large-area silicon wafers difficult to manufacture and more prone to damage, resulting in higher costs when replacing large-area silicon wafers in photovoltaic modules; and thirdly, the solder ribbon has these defects, which affect the overall power generation efficiency of solar silicon wafers.
[0003] Therefore, it is necessary to develop a solar silicon wafer connection structure and photovoltaic module to improve the overall power generation efficiency of solar silicon wafers. Summary of the Invention
[0004] The purpose of this invention is to disclose a solar silicon wafer connection structure and a photovoltaic module. Copper strips are adhered to the splicing seams between silicon wafers by conductive adhesive. The current generated by the silicon wafers under light irradiation is conducted through the copper strips. The conductivity of the copper strips is better than that of solder strips. Furthermore, the copper strips adhere to the splicing seams between the silicon wafers, resulting in a smaller area of the silicon wafers covered by light, which can improve the overall power generation efficiency of the photovoltaic module.
[0005] To achieve the first objective mentioned above, this invention provides a solar silicon wafer connection structure in which several rectangular silicon wafers are spliced together to form a horizontal splicing seam and a vertical splicing seam. A horizontal copper strip is bonded to the horizontal splicing seam with conductive adhesive, and a vertical copper strip is bonded to the vertical splicing seam with conductive adhesive.
[0006] Preferably, the width of the transverse copper strip is 3mm-10mm, the thickness of the transverse copper strip is 12μm-100μm, the width of the longitudinal copper strip is 3mm-10mm, and the thickness of the longitudinal copper strip is 12μm-100μm.
[0007] Preferably, the silicon wafer has a size of (10-20)cm*(15-30)cm.
[0008] Preferably, a nano-silver wire resin layer is coated in the area enclosed by the transverse copper strip and the longitudinal copper strip, and the nano-silver wire resin layer is a transparent layer.
[0009] Preferably, the conductive adhesive is a liquid adhesive or a film adhesive.
[0010] Preferably, the volume resistivity of the conductive adhesive is 1×10⁻⁶. -5 Ω*cm~10×10 -5 Ω*cm.
[0011] Preferably, the conductive adhesive comprises 20%-60% by weight of conductive particles, resin, and solvent;
[0012] The conductive particles include one or more of silver powder, copper powder, or nickel powder.
[0013] Preferably, the resin comprises at least one of acrylic resin, silicone resin, and polyurethane.
[0014] Preferably, the shape of the silver powder, copper powder, or nickel powder is one or a mixture of spherical, flake, snowflake, or dendritic shapes, and the particle size of the silver powder, copper powder, or nickel powder is 3μm-20μm.
[0015] To achieve the second objective of the invention, the present invention provides a photovoltaic module, including a frame assembly and a silicon wafer made of the solar silicon wafer connection structure described in the first invention.
[0016] Compared with the prior art, the beneficial effects of the present invention are:
[0017] (1) By splicing together smaller silicon wafers, copper strips are adhered to the splicing seams with conductive adhesive, so that only the edge part of the silicon wafer is blocked, thereby increasing the effective power generation area of the silicon wafer and improving power generation efficiency.
[0018] (2) The current generated by the silicon wafer under light is conducted through the copper strip. The copper strip has better conductivity than the solder strip, which can reduce the internal current consumption of the photovoltaic module.
[0019] (3) Small-area silicon wafers are cheaper to manufacture and less prone to breakage. Furthermore, the replacement cost is also lower when a single small-area silicon wafer breaks. Therefore, the photovoltaic module made from small-area silicon wafers in this invention has a cost advantage. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the solar silicon wafer connection structure of the present invention.
[0021] Among them, 1. silicon wafer; 11. transverse splicing seam; 12. longitudinal splicing seam; 2. transverse copper strip; 3. longitudinal copper strip. Detailed Implementation
[0022] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.
[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.
[0024] The specific implementation process of the present invention will be described below through several embodiments.
[0025] Example 1:
[0026] This embodiment discloses a solar silicon wafer interconnection structure. See [link to documentation]. Figure 1 Several rectangular silicon wafers 1 are spliced together to form a horizontal splicing seam 11 and a vertical splicing seam 12. A horizontal copper strip 2 is bonded to the horizontal splicing seam 11 with conductive adhesive, and a vertical copper strip 3 is bonded to the vertical splicing seam 12 with conductive adhesive.
[0027] Specifically, see Figure 1Traditional large-area silicon wafers are typically 30cm x 30cm. Several large-area silicon wafers are connected together using solder strips and interconnects, which suffers from drawbacks such as large areas of obstruction and significant internal current absorption when current passes through the solder strips. Therefore, smaller-area silicon wafers, which are less prone to breakage and have lower manufacturing costs, are used. These smaller wafers are typically (10-20)cm x (15-30)cm, preferably 15cm x 25cm. Several small rectangular silicon wafers 1 are spliced together to form horizontal splicing seams 11 and vertical splicing seams 12. Liquid conductive adhesive is applied to the horizontal splicing seams 11 and vertical splicing seams 12, or a conductive adhesive film is adhered to them. Finally, a horizontal copper strip 2 of a certain thickness is adhered to the horizontal splicing seams 11. A certain thickness of longitudinal copper strip 3 is adhered to the longitudinal splicing seam 12. That is, several small rectangular silicon wafers 1 are bonded together by copper strip and conductive adhesive. Copper strip is not bonded to the silicon wafer area except for the transverse splicing seam 11 and the longitudinal splicing seam 12. This makes only the edge part of the several small rectangular silicon wafers 1 blocked, which increases the effective power generation area of the silicon wafer and improves the power generation efficiency. In addition, copper strip consumes less current than solder strip, and small silicon wafers have the advantages of low manufacturing cost, less breakage and low maintenance cost.
[0028] To minimize the area of the silicon wafer obscured by the copper strips, the width of the horizontal copper strip 2 is 3mm-10mm, the thickness of the horizontal copper strip 2 is 12μm-100μm, the width of the vertical copper strip 3 is 3mm-10mm, and the thickness of the vertical copper strip 3 is 12μm-100μm. The width of the edge portion of the silicon wafer that is obscured is half the width of the horizontal copper strip 2 or the vertical copper strip 3, resulting in a small obscured area. The preferred dimensions of the horizontal and vertical copper strips are as follows.
[0029]
[0030] In Example 1, the conductive adhesive is a liquid adhesive or a film adhesive. The liquid adhesive is applied to the transverse splice seam 11 and the longitudinal splice seam 12, or the film adhesive is adhered to the transverse splice seam 11 and the longitudinal splice seam 12.
[0031] In a preferred embodiment, the conductive adhesive comprises 20%-60% by weight of conductive particles, resin, and solvent; the conductive particles include one or more of silver powder, copper powder, or nickel powder; the resin is selected as a weather-resistant resin, and the resin includes at least one of acrylic resin, silicone resin, and polyurethane; the shape of the silver powder, copper powder, or nickel powder is spherical, flake-shaped, snowflake-shaped, or dendritic, or a mixture thereof, and the particle size of the silver powder, copper powder, or nickel powder is 3μm-20μm. Specifically, flake-shaped, snowflake-shaped, or dendritic conductive particles increase the contact area and contact opportunities between conductive particles, thereby improving the conductivity of the conductive adhesive. The volume resistivity of the conductive adhesive used in Example 1 is 10⁻⁶. -5 ~10-4 Ω*cm. See the table below for the formulation of the conductive adhesive.
[0032]
[0033] The volume resistivity of conductive adhesive is affected by the content, type and shape of conductive particles. The conductive adhesive in Example 1 serves to conduct current and bond copper strips. Considering the volume resistivity and cost of conductive adhesive, the conductive adhesive formulation with serial number 4 is preferred.
[0034] Example 2:
[0035] Based on Example 1, if the area enclosed by the transverse copper strip 2 and the longitudinal copper strip 3 is large, the current generated by the silicon wafer far from the transverse copper strip 2 and the longitudinal copper strip 3 will not be able to be conducted to the copper strips. In order to further expand the effective power generation area of the silicon wafer, a nano-silver wire resin layer is coated in the area enclosed by the transverse copper strip 2 and the longitudinal copper strip 3. The nano-silver wire resin layer is a transparent layer. Specifically, the nano-silver wire resin layer contains a certain amount of nano-silver wires. The nano-silver wires are in contact with each other, making the nano-silver wire resin layer a conductive layer. By using a transparent resin, the current generated by the silicon wafer in the area enclosed by the transverse copper strip 2 and the longitudinal copper strip 3 is conducted to the transverse copper strip 2 and the longitudinal copper strip 3 through the nano-silver wire resin layer while minimizing light reflection, thus increasing the effective power generation area of the silicon wafer.
[0036] Example 3:
[0037] Based on Example 1, if the area enclosed by the horizontal copper strip 2 and the vertical copper strip 3 is large, the current generated by the silicon wafer far from the horizontal copper strip 2 and the vertical copper strip 3 will not be able to be conducted to the copper strip. In order to further expand the effective power generation area of the silicon wafer, several grid lines are set in the area enclosed by the horizontal copper strip 2 and the vertical copper strip 3. The current generated on the surface of the silicon wafer is collected to the horizontal copper strip 2 and the vertical copper strip 3 through the grid lines, thereby increasing the effective power generation area of the silicon wafer.
[0038] Example 4:
[0039] This embodiment discloses a photovoltaic module, including a frame assembly and silicon wafers made of the solar silicon wafer connection structure described in Embodiment 1, Embodiment 2, or Embodiment 3. Specifically, several small-area rectangular silicon wafers 1 are connected in series by horizontal copper strips 2 and vertical copper strips 3 to form the power-generating silicon wafers of the photovoltaic module. The power conversion efficiency can reach 24.8%, and the manufacturing cost is relatively low, as is the subsequent maintenance cost.
[0040] The photovoltaic module disclosed in this embodiment has the same technical solutions as those in Embodiments 1, 2, and 3. Please refer to Embodiments 1, 2, and 3 for details, which will not be repeated here.
Claims
1. A solar silicon wafer connection structure, characterized in that, Several small silicon wafers with dimensions of (10~20) cm * (15~30) cm are spliced together to form horizontal and vertical splicing seams. The horizontal copper strip passes through a material with a volume resistivity of 1×10⁻⁶. -5 Ω*cm~10×10 -5 Conductive adhesive with a resistivity of Ω*cm is bonded to the transverse splice seam, and the longitudinal copper strip passes through a material with a volume resistivity of 1×10⁻⁶. -5 Ω*cm~10×10 -5 The conductive adhesive with an Ω*cm thickness is bonded to the longitudinal splicing seam; the width of the transverse copper strip is 3mm or 10mm, the thickness of the transverse copper strip is 12μm-30μm, the width of the longitudinal copper strip is 3mm or 10mm, and the thickness of the longitudinal copper strip is 12μm-30μm. The transverse copper strip, the longitudinal copper strip, and the conductive adhesive bond several rectangular silicon wafers together. Except for the transverse splicing seam and the longitudinal splicing seam, no copper strip is bonded to the silicon wafer area. The width of the edge portion of the silicon wafer that is blocked is half the width of the horizontal or vertical copper strip; A nano-silver wire resin layer is coated in the area enclosed by the transverse copper strip and the longitudinal copper strip. The current generated by the silicon wafer is conducted to the transverse copper strip and the longitudinal copper strip through the nano-silver wire resin layer. The conductive adhesive comprises 20%-60% by weight of conductive particles, resin and solvent, wherein the resin comprises at least one of acrylic resin, silicone resin and polyurethane. The conductive particles include one or more of silver powder, copper powder, or nickel powder.
2. The solar silicon wafer connection structure as described in claim 1, characterized in that, The silver nanowire resin layer is a transparent layer.
3. The solar silicon wafer connection structure as described in claim 1, characterized in that, The conductive adhesive is a liquid adhesive or a film adhesive.
4. The solar silicon wafer connection structure as described in claim 1, characterized in that, The shape of the silver powder, copper powder, or nickel powder is one or a mixture of spherical, flake, snowflake, or dendritic, and the particle size of the silver powder, copper powder, or nickel powder is 3μm-20μm.
5. A photovoltaic module, characterized in that, The silicon wafer includes a frame assembly and a solar silicon wafer connection structure as described in any one of claims 1-4.