Back contact battery and scratch-proof method thereof

Abstract

The invention provides a back contact battery and a scratch-proof method thereof. The back surface of the back contact battery comprises a plurality of fine grids and a plurality of lug bosses; wherein the protruding parts are located between every two adjacent fine grids and close to the ends of the fine grids, and the thickness of the protruding parts is larger than that of the fine grids. According to the back contact battery, the lug bosses are arranged on the back surface of the back contact battery, so that a gap can be formed between adjacent batteries when the back contact batteries are stacked together, and the effect of protecting the batteries from being scratched can be achieved; and on the other hand, the lug boss is arranged on the back surface of the back contact battery, the front surface of the battery is not shielded by light, and the battery efficiency is not reduced.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of solar cells, and in particular to a back contact cell and an anti-scratch method thereof. Background Art

[0002] BC solar cell refers to back contact solar cell. Its main feature is that the PN junction and gate electrode are set on the back of the cell, and there is no light blocking on the front. The cell has a larger light receiving area, a larger short-circuit current, a higher conversion efficiency and a higher power generation capacity.

[0003] However, since there is no metal grid line on the front of the BC battery, when the batteries are stacked together, the velvet surface on the front cannot create a gap with the adjacent batteries, and it is easy to cause friction with the adjacent batteries, causing the front of the battery to be scratched, thereby affecting the battery efficiency and even scrapping the battery cell. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a back-contact battery and an anti-scratch method thereof, so as to solve the problem of scratches on the front side of the back-contact battery.

[0005] In order to solve the above technical problems, the present invention provides a back-contact battery, the back side of which includes a plurality of fine grids and a plurality of raised portions; wherein the raised portion is located between two adjacent fine grids and close to the ends of the fine grids, and the thickness of the raised portion is greater than the thickness of the fine grids.

[0006] Optionally, the material of the protrusion includes EVA film, epoxy resin or ink.

[0007] Optionally, the thickness of the protrusion is 10 μm to 30 μm.

[0008] Optionally, the shape of the protrusion is rectangular, circular or polygonal.

[0009] Optionally, when the shape of the protrusion is a rectangle, the length of the rectangle is 100-500 μm, and the width of the rectangle is 50-200 μm.

[0010] Optionally, the fine gates include p-pole fine gates and n-pole fine gates, and the p-pole fine gates and the n-pole fine gates are arranged in a staggered manner.

[0011] Optionally, a main grid is further included, and the main grid is located in a vertical direction of the fine grid and is electrically connected to the fine grid.

[0012] In order to solve the above technical problems, the present invention provides a method for anti-scratch of a back-contact battery, comprising: after forming a plurality of fine grids on the back side of the back-contact battery, forming a plurality of protrusions on the back side of the back-contact battery, the protrusions are located between two adjacent fine grids and close to the ends of the fine grids, and the thickness of the protrusions is greater than the thickness of the fine grids.

[0013] Optionally, forming a plurality of raised portions on the back side of the back-contact battery comprises: providing a printed adhesive film screen, the printed adhesive film screen comprising a plurality of openings, the positions of the openings corresponding to the positions of the raised portions; covering the printed adhesive film screen on the back side of the back-contact battery, and printing slurry at the openings; and curing the slurry to obtain the plurality of raised portions.

[0014] Optionally, the slurry includes EVA film, epoxy resin or ink.

[0015] Optionally, the thickness of the slurry is adjustable, and the size of the opening is adjustable.

[0016] Compared with the prior art, the present invention has the following advantages: The back contact battery and the anti-scratch method thereof of the present invention can ensure that when the back contact batteries are stacked together, there is a gap between adjacent batteries, which can protect the batteries from being scratched; on the other hand, the protrusion is set on the back of the back contact battery, and the front of the battery is not blocked from light, which will not reduce the battery efficiency; the back contact battery of the present application sets the protrusion at the end close to the fine grid, which can effectively support all grid lines and prevent the grid lines from rubbing against adjacent batteries; the back contact battery of the present application sets the protrusion between two adjacent fine grids, which can prevent the battery area between the grid lines from bending due to gravity and forming friction with adjacent batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings: Figure 1 is a schematic diagram of a back contact cell according to an embodiment of the present invention.

[0018] Figure 2 is a flow chart of forming a plurality of protrusions on the back side of a back contact cell according to an embodiment of the present invention.

[0019] Figure 3 Schematic diagram of a printing film screen according to an embodiment of the present invention.

[0020] 11p Ultra Fine Gate 12 n ultra-fine grid 13 Main grid 14 Soldering Points 15 Raised part 300 Printing Film Screen 31 Opening DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0022] Since there is no metal grid on the front of the back contact battery, when the batteries are stacked together, the velvet surface on the front cannot form a gap with the adjacent batteries, and it is easy to rub against the adjacent batteries, causing scratches on the front of the battery. In response to the above problems, the existing method generally applies ink on the front of the battery. After the ink is sprayed on the front, the battery is blocked from light to a certain extent, which has a greater impact on the short-circuit current density of the battery, thereby reducing the battery efficiency and reducing the advantages of the back contact battery.

[0023] The present invention provides a raised portion on the back side of the back contact battery, thereby ensuring that there is a gap between adjacent batteries when the back contact batteries are stacked together, thereby protecting the batteries from being scratched. On the other hand, by providing the raised portion on the back side of the back contact battery, there is no light obstruction on the front side of the battery, and the battery efficiency will not be reduced.

[0024] Figure 1 Schematic diagram of a back contact battery according to an embodiment of the present invention. Figure 1 As shown, the back contact cell 100 includes a p-pole fine grid 11 , an n-pole fine grid 12 , a main grid 13 , a solder joint 14 and a protrusion 15 .

[0025] Among them, the thickness of the raised portion 15 is greater than the thickness of the p-pole fine gate 11, and the thickness of the raised portion 15 is greater than the thickness of the n-pole fine gate 12. Preferably, the thickness of the raised portion 15 is greater than the thickness of the main gate 13. In short, the raised portion 15 needs to be higher than the height of the gate line. The height of the gate line is about 10um. Optionally, the thickness of the raised portion 15 is 10μm~30μm. By arranging a raised portion on the back side of the back contact battery, the present invention can ensure that there is a gap between adjacent batteries when the back contact batteries are stacked together, which can protect the batteries from being scratched; in addition, arranging a raised portion on the back side of the back contact battery can reduce light loss and will not reduce battery efficiency.

[0026] Continue to refer Figure 1, the p-pole fine gate 11 and the n-pole fine gate 12 are parallel to each other, and the p-pole fine gate 11 and the n-pole fine gate 12 are arranged alternately. The main gate 13 is located in the vertical direction of the p-pole fine gate 11 and the n-pole fine gate 12 and is electrically connected to the p-pole fine gate 11 or the n-pole fine gate 12. For the p-pole fine gate 11 or the n-pole fine gate 12, the end electrically connected to the main gate 13 is called the upper end, and the other end is called the lower end.

[0027] like Figure 1 As shown, the protrusion 15 near the upper end of the p-pole fine gate 11 is located between two adjacent p-pole fine gates 11. The protrusion 15 near the lower end of the p-pole fine gate 11 is located between the adjacent p-pole fine gate 11 and n-pole fine gate 12. Similarly, the protrusion 15 near the upper end of the n-pole fine gate 12 is located between two adjacent n-pole fine gates 12. The protrusion 15 near the lower end of the n-pole fine gate 12 is located between the adjacent p-pole fine gate 11 and n-pole fine gate 12.

[0028] The back-contact battery of the present application sets the raised portion at the end close to the fine grid, which can effectively support all grid lines and prevent the grid lines from rubbing against adjacent batteries; the raised portion of the back-contact battery of the present application is set between two adjacent fine grids, which can prevent the battery area between the grid lines from bending due to gravity and forming friction with adjacent batteries.

[0029] In this embodiment, the back-contact cell 100 includes two busbars 13 .

[0030] In some embodiments, the back contact battery may include more than two main grids. The increase in the number of main grids brings many benefits in battery manufacturing. For example, due to the increase in the number of main grids, the width of each main grid can become very thin, thereby saving the total amount of silver paste and reducing costs. In addition, when the current is collected by the fine grid to the main grid, a part of the power will be lost on the fine grid, but now due to the increase in the number of main grids, the distance that the current flows on the fine grid to reach the main grid is shortened, and the power loss is reduced, thereby increasing the power generation capacity of the photovoltaic module.

[0031] In some embodiments, the back contact cell does not include a main grid, and the fine grid is directly connected to the welding ribbon through a welding spot, which is the 0BB technology. The so-called 0BB is a "busbar-free" technology. BB stands for "Busbar", which is the main grid on the photovoltaic cell, and the number in front represents the number of main grids. 0BB has obvious advantages and has become a hot spot for the next round of technological competition. The main advantages of 0BB technology are as follows: 1) The transmission path of current in the fine grid in 0BB is shorter, which reduces power loss; 2) 0BB technology removes the main grid, reduces the consumption of battery silver paste, and reduces costs; 3) In 0BB technology, due to smaller and more welding spots, the stress distribution of the battery is more uniform, thereby reducing the fragmentation rate, broken grid rate and hidden cracks of the battery cell, so that the yield of product production is improved.

[0032] Optionally, the shape of the protrusion includes but is not limited to a rectangle, a circle or a polygon.

[0033] Optionally, when the shape of the raised portion is a rectangle, the length of the rectangle is 100-500 μm, and the width of the rectangle is 50-200 μm. The shape and size of the raised portion can be adjusted according to actual needs. The raised portion is as small as possible to reduce shading, while also playing a supporting role.

[0034] Optionally, the material of the raised portion includes but is not limited to EVA film, epoxy resin or ink. Preferably, the material of the raised portion is epoxy resin, which has better light transmittance and friction resistance than ink.

[0035] The present application also provides a method for preventing scratches on a back-contact battery. The method for preventing scratches on a back-contact battery includes: after forming a plurality of fine grids on the back side of the back-contact battery, forming a plurality of protrusions on the back side of the back-contact battery, wherein the protrusions are located between two adjacent fine grids and close to the ends of the fine grids, and the thickness of the protrusions is greater than the thickness of the fine grids.

[0036] Figure 2 FIG. 1 is a flow chart of forming a plurality of protrusions on the back side of a back contact battery according to an embodiment of the present invention. Figure 2 As shown, the method 200 for forming a plurality of protrusions on the back side of a back contact cell includes: Step S21: providing a printing film screen, wherein the printing film screen comprises a plurality of openings, and positions of the openings correspond to positions of the protruding portions.

[0037] Figure 3 Schematic diagram of a printing film screen according to an embodiment of the present invention. Figure 3 As shown, the printing film screen 300 includes a plurality of openings 31. The positions of the openings 31 correspond to the positions of the protrusions to be generated. The film thickness of the printing film screen 300 is adjustable (between 4 and 20 μm), and the size of the openings 31 is adjustable (between 90 and 480 μm in length and between 40 and 180 μm in width).

[0038] Step S22: Cover the back side of the back contact battery with a printed film screen and print the paste at the opening.

[0039] The slurry includes but is not limited to EVA film, epoxy resin or ink.

[0040] Step S23: solidifying the slurry to obtain a plurality of protrusions.

[0041] Taking the slurry as EVA film as an example, after the solar cell is printed and sintered, the EVA film is printed on the opening area of ​​the printed film screen. The length and width of the printed rectangle can be adjusted (length is between 100-500um, width is between 50-200um), and the thickness of the printed film can be adjusted according to the printing area and graphics, the thickness is between 10um~30um, and then cured in a 200℃ drying and curing furnace for 15 minutes. After the curing is completed, the EVA film is dried and exposed to the air. The part is no longer sticky and will not stick to other batteries. In addition, the cured EVA film is very soft and will not damage the battery surface when in contact with the battery; it also has high light transmittance and will not reduce the secondary absorption of sunlight.

[0042] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0043] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0044] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0045] As shown in this application, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0046] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0047] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0048] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0049] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0050] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0051] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of the present application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the subject of the present application requires more features than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0052] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers allow a change of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification are approximate values, which can be changed according to the required characteristics of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the method of general digit retention. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0053] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the present application.

Claims

1. A back contact battery, characterized in that: The back side of the back contact cell includes a plurality of fine grids and a plurality of protrusions; The protrusion is located between two adjacent fine grids and close to the ends of the fine grids, and the thickness of the protrusion is greater than the thickness of the fine grids.

2. The back contact cell according to claim 1, characterized in that The material of the protruding portion includes EVA film, epoxy resin or ink.

3. The back contact cell according to claim 1, characterized in that The thickness of the protrusion is 10 μm to 30 μm.

4. The back contact cell according to claim 1, characterized in that The shape of the protrusion is rectangular, circular or polygonal.

5. The back contact cell according to claim 4, characterized in that When the shape of the protrusion is a rectangle, the length of the rectangle is 100-500 μm, and the width of the rectangle is 50-200 μm.

6. The back contact cell according to claim 1, characterized in that The fine gates include a p-pole fine gate and an n-pole fine gate, and the p-pole fine gate and the n-pole fine gate are arranged in a staggered manner.

7. The back contact cell according to claim 1, characterized in that It also includes a main grid, which is located in a vertical direction of the fine grid and is electrically connected to the fine grid.

8. A method for preventing scratches on a back contact battery, characterized in that: include: After forming a plurality of fine grids on the back side of the back contact battery, a plurality of protrusions are formed on the back side of the back contact battery. The protrusions are located between two adjacent fine grids and close to the ends of the fine grids. The thickness of the protrusions is greater than the thickness of the fine grids.

9. The method for preventing back contact batteries from being scratched as claimed in claim 8, characterized in that: Forming a plurality of protrusions on the back side of the back contact battery comprises: Provided is a printing film screen, the printing film screen comprising a plurality of openings, the positions of the openings corresponding to the positions of the protruding portions; Covering the printed film screen on the back side of the back contact battery, and printing slurry at the opening; The slurry is cured to obtain the plurality of protrusions.

10. The method for preventing back contact batteries from being scratched as claimed in claim 9, characterized in that: The thickness of the slurry is adjustable, and the size of the opening is adjustable.

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