Back contact cell, cell assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of back contact cells, and provides a back contact cell, a cell assembly and a photovoltaic system. The back contact cell comprises a silicon substrate, one surface of the silicon substrate is provided with a plurality of insulating glue, and the other surface of the silicon substrate is provided with a plurality of welding strips; wherein the shrinkage rate of the insulation paste is 0%-12%. According to the utility model, the plurality of insulating glues are arranged on the other surface of the silicon substrate provided with the welding strip, and the pulling force direction of the insulating glues to the back contact battery is opposite to the pulling force direction of the welding strip to the back contact battery, so that the pulling force applied by the welding strip to the back contact battery can be effectively counteracted, and the back contact battery is prevented from bending or deforming; and the effects of improving the structural stability of the back contact battery and improving the battery performance of the back contact battery are achieved.

Description

[0001] This application claims priority to Chinese Patent Application No. 2024221951576, filed on September 6, 2024, entitled "Back Contact Battery, Battery Module and Photovoltaic System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This utility model relates to the field of photovoltaic technology, and in particular to a back contact battery, battery module and photovoltaic system. Background Technology

[0003] A back-contact battery is a device that converts sunlight into electrical energy using the photoelectric effect. It is primarily made of photovoltaic materials (such as silicon), which absorb photons to excite electrons and generate an electric current. The battery consists of a front electrode, a photovoltaic layer, and a back electrode, and can generate electricity under sunlight. It is widely used in power generation systems and various electronic devices.

[0004] In the prior art, after the welding strip is installed on the back contact battery, the battery often experiences bending due to the tension applied by the welding strip, which in turn affects the battery performance. Utility Model Content

[0005] This invention provides a back-contact battery, a battery module, and a photovoltaic system to solve the problem of easy bending of back-contact batteries in the prior art.

[0006] This utility model is implemented as follows: it provides a back-contact battery, a battery module, and a photovoltaic system. The back-contact battery includes a silicon substrate, one side of which is provided with a plurality of insulating adhesives, and the other side of which is provided with a plurality of solder strips; wherein the shrinkage rate of the insulating adhesive is 0% to 12%.

[0007] Furthermore, the light transmittance of the insulating adhesive is greater than or equal to 95%.

[0008] Furthermore, the thickness of the insulating adhesive is 50 hm to 800 hm.

[0009] Furthermore, the hardness of the insulating adhesive is between 50 Shore D and 95 Shore D.

[0010] Furthermore, the insulating adhesive is a UV insulating adhesive, an epoxy insulating adhesive, or an acrylic insulating adhesive.

[0011] Furthermore, the insulating adhesive is a transparent insulating adhesive.

[0012] Furthermore, the insulating adhesive is a fluorescent transparent insulating adhesive.

[0013] This utility model embodiment also provides a battery assembly, which includes a back contact battery as described above.

[0014] This utility model embodiment also provides a photovoltaic system, which includes the battery module as described above.

[0015] This invention provides a back-contact battery, a battery module, and a photovoltaic system. The back-contact battery includes a silicon substrate, one side of which is provided with a plurality of insulating adhesives, and the other side of which is provided with a plurality of solder ribbons; wherein the shrinkage rate of the insulating adhesives is 0% to 12%. This invention, by providing a plurality of insulating adhesives on the side of the silicon substrate opposite to the direction of the tensile force exerted by the insulating adhesives on the back-contact battery, effectively counteracts the tensile force exerted by the solder ribbons on the back-contact battery, preventing the back-contact battery from bending or deforming, thereby improving the structural stability and battery performance of the back-contact battery. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the photovoltaic system provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a battery assembly provided in an embodiment of the present utility model;

[0019] Figure 3 A schematic diagram of one side of the silicon substrate of the back contact battery provided in an embodiment of this utility model;

[0020] Figure 4 This is a schematic diagram of the other side of the silicon substrate of the back contact battery provided in an embodiment of the present invention.

[0021] Explanation of key component symbols: 1000, photovoltaic system; 1001, battery module; 100, back contact battery; 101, silicon substrate; 10, insulating adhesive; 20, solder ribbon. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present utility model, and should not be construed as limiting the present utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0023] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model 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 limitations on this utility model.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0028] Please see Figure 1 and Figure 2 The photovoltaic system 1000 in this embodiment of the present invention may include a battery module 1001, which may include a plurality of battery strings, and each battery string may include a plurality of back-contact batteries 100. In this invention, the plurality of back-contact batteries 100 in the battery module 1001 can be sequentially connected together via solder strips 20 to form a battery string. The battery strings in the battery module 1001 can be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output; for example, the connection between the battery strings can be achieved through busbars.

[0029] Please see Figure 3 and Figure 4 In this embodiment of the present invention, the back contact battery 100 can be a single battery cell, or it can be a half-cell, a third-cell, or other proportioned battery cell divided from a single battery cell. It should be noted that the accompanying drawings provided in this application are schematic diagrams, and some elements are not shown in the drawings. The purpose is to clearly describe the technical solution and highlight the key points of the utility model. It is not intended to limit the technical solution to exclude these unshown elements. That is to say, the accompanying drawings are only examples and do not represent a limitation on the specific form of the back contact battery 100.

[0030] Furthermore, Figure 3 and Figure 4 The back contact battery 100 includes: a silicon substrate 101, one side of the silicon substrate 101 is provided with a plurality of insulating adhesives 10, and the other side of the silicon substrate 101 is provided with a plurality of solder ribbons 20.

[0031] Specifically, the silicon substrate 101 includes a front side and a back side. The front side faces the sun and mainly receives direct sunlight, while the back side faces the mounting surface of the cell assembly 1001 and mainly receives sunlight reflected from the mounting surface, such as the ground or a roof. Alternatively, the back side is the side of the back contact cell 100 with the grid lines. Furthermore, the silicon substrate 101 has a stacked doped layer and a passivation layer. The doped layer can connect with the grid lines to establish an ohmic contact. The front side of the silicon substrate 101 is the other side of the front side of the silicon substrate 101.

[0032] The solder ribbon 20 is disposed on the back side of the silicon substrate 101, and the insulating adhesive 10 is disposed on the front side of the silicon substrate 101. The shrinkage rate of the insulating adhesive 10 is 0% to 12%.

[0033] Specifically, in the prior art, gate lines are formed on the back side of the silicon substrate 101, and solder ribbons 20 are formed on the gate lines. In the prior art, after the solder ribbons 20 are installed, the back contact cell 100 often encounters bending problems caused by the tension applied by the solder ribbons 20. Bending of the back contact cell 100 will lead to a decrease in the mechanical strength of the back contact cell 100, damage to the back contact cell 100, and a decrease in the performance of the back contact cell 100.

[0034] Therefore, to counteract the bending of the back contact battery 100 caused by the solder ribbon 20, in this embodiment of the invention, a plurality of insulating adhesives 10 are also provided on the silicon substrate 101. The insulating adhesives 10 are provided on the front side of the silicon substrate 101 and, like the solder ribbon 20, exert a tensile force on the back contact battery 100, bending the solder ribbon 20. However, since the insulating adhesives 10 and the solder ribbon 20 are specifically provided on opposite sides of the silicon substrate 101 of the back contact battery 100, the tensile forces exerted by the insulating adhesives 10 and the solder ribbon 20 on the back contact battery 100 are in opposite directions, and therefore the bending directions of the back contact battery 100 are also opposite. Therefore, by providing a plurality of insulating adhesives 10 on the other side of the silicon substrate 101 where the solder ribbon 20 is provided, the direction of the pulling force of the insulating adhesive 10 on the back contact battery 100 is opposite to the direction of the pulling force of the solder ribbon 20 on the back contact battery 100, which can effectively counteract the pulling force applied by the solder ribbon 20 on the back contact battery 100, prevent the back contact battery 100 from bending or deforming, and achieve the effect of improving the structural stability of the back contact battery 100 and improving the battery performance of the back contact battery 100.

[0035] Furthermore, in this invention, the shrinkage rate of the insulating adhesive 10 is between 0% and 12%. Setting the shrinkage rate of the insulating adhesive 10 to between 0% and 12% can reduce the deformation caused by adhesive shrinkage, maintain the stability of the silicon substrate 101, and the insulating adhesive 10 can also provide a certain degree of elasticity and adjustment space, control the stress generated by the shrinkage of the insulating adhesive 10, and help alleviate the impact of the tensile force applied by the solder ribbon 20 on the structure of the back contact battery 100.

[0036] In such embodiments, the shrinkage rate of the insulating adhesive 10 may be, for example, any value within the range of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, or 0% to 12%.

[0037] Please note that the shrinkage rate of insulating adhesive 10 refers to the degree to which the volume or size of the adhesive decreases relative to its initial state during the curing or drying process. Shrinkage rate is usually expressed as a percentage.

[0038] It is understood that the shrinkage rate of the insulating adhesive 10 provided in this embodiment refers to the shrinkage rate obtained by testing the insulating adhesive 10 in an environment with a temperature of 80°C to 150°C and a curing time of 20 minutes. The table below shows the shrinkage rate and tensile strength of the insulating adhesive 10 in different environments in this embodiment.

[0039] Serial Number temperature Tensile strength Curing time Shrinkage 1 100℃ 15-30 MPa 20 minutes 0.05％-0.1％ 2 110℃ 30-45 MPa 20 minutes 0.1％-0.15％ 3 120℃ 45-60 MPa 20 minutes 0.32％-0.77％ 4 130℃ 45-60 MPa 20 minutes 1％-5％

[0040] It can be understood that the shrinkage rate of the insulating adhesive 10 is 0% to 12%, which can increase the tensile strength of the insulating adhesive 10, thereby reducing the deformation caused by the shrinkage of the adhesive, maintaining the stability of the silicon substrate 101, and the insulating adhesive 10 can also provide a certain degree of elasticity and adjustment space, control the stress generated by the shrinkage of the insulating adhesive 10, and help alleviate the impact of the tension applied by the solder ribbon 20 on the structure of the back contact battery 100.

[0041] Furthermore, in this invention, the insulating adhesive 10 disposed on the front side of the silicon substrate 101 can be disposed before the solder ribbon 20 is disposed. This is because after the solder ribbon 20 is disposed, the back contact battery 100 has already bent, making it difficult to dispose of the insulating adhesive 10 on the front side of the back contact battery 100.

[0042] Optionally, in one possible implementation, the insulating adhesive 10 is a UV insulating adhesive 10, an epoxy insulating adhesive 10, or an acrylic insulating adhesive 10. Preferably, the insulating adhesive 10 can be set as a UV insulating adhesive 10 because UV insulating adhesive 10 has the advantages of high light transmittance and relatively stable adhesive state.

[0043] Furthermore, in one possible implementation, the light transmittance of the insulating adhesive 10 is greater than or equal to 95%.

[0044] Specifically, in this invention, by setting the light transmittance of the insulating adhesive 10 to be greater than or equal to 95%, the light blocking effect of the insulating adhesive 10 can be reduced, thereby improving the light energy conversion efficiency of the back contact battery 100. In such embodiments, the light transmittance of the insulating adhesive 10 can be, for example, any value within the range of 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or greater than 95%.

[0045] Furthermore, in one possible implementation, the thickness of the insulating adhesive 10 is 50 hm to 800 hm.

[0046] Specifically, in this invention, when the thickness of the insulating adhesive 10 is too thin, the tensile force of the insulating adhesive 10 on the back contact battery 100 is insufficient, and it cannot effectively counteract the tensile force of the solder ribbon 20 on the back contact battery 100. When the thickness of the insulating adhesive 10 is too thick, it increases costs, wastes the insulating adhesive 10, and may cause the tensile force of the insulating adhesive 10 on the back contact battery 100 to be too large. Therefore, by setting the thickness of the insulating adhesive 10 to be within the range of 50hm to 800hm, the tensile force of the solder ribbon 20 on the back contact battery 100 can be effectively counteracted without wasting the insulating adhesive 10. In such embodiments, the thickness of the insulating adhesive 10 can be, for example, 50hm, 60hm, 70hm, 80hm, 90hm, 100hm, 200hm, 300hm, 400hm, 500hm, 600hm, 700hm, 800hm, or any value within the range of 50hm to 800hm.

[0047] Furthermore, in one possible implementation, the hardness of the insulating adhesive 10 is 50 Shore D to 95 Shore D.

[0048] Specifically, the hardness of insulating adhesive 10 refers to the adhesive's ability to resist deformation after curing.

[0049] In this embodiment of the invention, by setting the hardness of the insulating adhesive 10 to within the range of 50 Shore D to 95 Shore D, the tensile force of the insulating adhesive 10 on the back contact battery 100 can be increased, thereby better counteracting the tensile force of the solder ribbon 20 on the back contact battery 100. Furthermore, the flexibility and elasticity of the insulating adhesive 10 can be maintained, resulting in cost savings. In such an embodiment, the thickness of the insulating adhesive 10 can be, for example, any value within the range of 50 Shore D, 55 Shore D, 60 Shore D, 65 Shore D, 70 Shore D, 80 Shore D, 85 Shore D, 90 Shore D, 95 Shore D, or 50 Shore D to 95 Shore D.

[0050] Furthermore, in one possible implementation, the projection of the insulating adhesive 10 in the thickness direction of the silicon substrate 101 at least partially overlaps with the projection of the solder ribbon 20 in the thickness direction of the silicon substrate 101.

[0051] Specifically, in this invention, the projection of the insulating adhesive 10 in the thickness direction of the silicon substrate 101 is at least partially overlapped with the projection of the solder ribbon 20 in the thickness direction of the silicon substrate 101. Preferably, the projection of the insulating adhesive 10 in the thickness direction of the silicon substrate 101 and the projection of the solder ribbon 20 in the thickness direction of the silicon substrate 101 can completely overlap.

[0052] Because the insulating adhesive 10 is preferably positioned corresponding to the solder ribbon 20, with the projections of the insulating adhesive 10 and the solder ribbon 20 in the thickness direction of the silicon substrate 101 partially or completely overlapping, force balance can be maximized. This overlapping configuration ensures that the insulating adhesive 10 effectively resists the tensile force applied by the solder ribbon 20, thereby further reducing cell bending. Furthermore, a completely overlapping configuration may provide a more uniform stress distribution, contributing to improved overall stability of the back contact cell 100.

[0053] The insulating adhesive 10 is specifically designed to correspond with the solder ribbon 20. Since the solder ribbon 20 is designed in strip form, the insulating adhesive 10 can also be designed in strip form on the silicon substrate 101.

[0054] Furthermore, regarding the material of the insulating adhesive 10, in one possible implementation, the insulating adhesive 10 is a transparent insulating adhesive 10.

[0055] Specifically, by setting the insulating adhesive 10 to be transparent, the shading of sunlight by the insulating adhesive 10 can be reduced, allowing more sunlight to be absorbed by the back contact battery 100, thereby improving the photoelectric conversion efficiency of the back contact battery 100. Furthermore, by setting the insulating adhesive 10 to be transparent, the electrical structure underneath can be observed through the insulating adhesive 10, facilitating inspection and positioning, and ensuring quality control during the manufacturing process.

[0056] Furthermore, regarding the material of the insulating adhesive 10, in one possible implementation, the insulating adhesive 10 is a fluorescent transparent insulating adhesive 10.

[0057] Thus, the insulating adhesive 10 will glow under illumination of a light source of the corresponding wavelength, making it easier to detect the position of the insulating adhesive 10 and improving the accuracy of setting the insulating adhesive 10 in the back contact battery 100. Furthermore, the fact that the insulating adhesive 10 is a fluorescent transparent insulating adhesive 10 allows it to possess both transparent and fluorescent properties, thereby improving the accuracy of setting the insulating adhesive 10 in the back contact battery 100 while reducing the amount of sunlight blocked by the insulating adhesive 10.

[0058] In the description of this specification, the references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] Furthermore, the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back-contact battery, characterized in that, include: A silicon substrate, wherein one side of the silicon substrate is provided with a plurality of insulating adhesives and the other side of the silicon substrate is provided with a plurality of solder strips; The shrinkage rate of the insulating adhesive is 0% to 12%.

2. The back contact battery according to claim 1, characterized in that, The light transmittance of the insulating adhesive is greater than or equal to 95%.

3. The back contact battery according to claim 1, characterized in that, The thickness of the insulating adhesive is 50 hm to 800 hm.

4. The back contact battery according to claim 1, characterized in that, The hardness of the insulating adhesive is 50 Shore D to 95 Shore D.

5. The back contact battery according to claim 1, characterized in that, The insulating adhesive is a UV insulating adhesive, an epoxy insulating adhesive, or an acrylic insulating adhesive.

6. The back contact battery according to claim 1, characterized in that, The projection of the insulating adhesive in the thickness direction of the silicon substrate at least partially overlaps with the projection of the solder strip in the thickness direction of the silicon substrate.

7. The back contact battery according to claim 1, characterized in that, The insulating adhesive is a transparent insulating adhesive.

8. The back contact battery according to claim 7, characterized in that, The insulating adhesive is a fluorescent transparent insulating adhesive.

9. A battery assembly, characterized in that, Includes the back contact battery as described in any one of claims 1 to 8.

10. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 9.

Images