Battery strings and photovoltaic modules

Abstract

The utility model discloses a battery string and a photovoltaic module. The battery string includes a plurality of battery cells, a metal interconnection bar and a transparent conductive film, wherein the transparent conductive film includes a transparent substrate layer prepared from a transparent polymer substrate material and metal nanowires, wherein the metal nanowires are connected to the surface of the transparent substrate layer by printing or deposition, wherein a plurality of battery cells are placed in sequence, wherein the positive and negative electrodes of adjacent battery cells are connected by the metal interconnection bar, wherein the light-receiving surface and the backlight surface of the battery cell are respectively connected to the transparent conductive film, wherein the metal nanowires on the transparent conductive film are perpendicular to the secondary grid lines on the battery cell, and the ends of the metal nanowires are also connected to the metal interconnection bar. The present application has the advantages of small square resistance and high light transmittance, can reduce light reflection, avoid metal interconnection bars from blocking silicon wafers, and is conducive to improving the power of photovoltaic modules.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, in particular to a battery string and a photovoltaic component. Background Art

[0002] In the photovoltaic field, the advantage of 0BB technology is that it removes the main grid structure and reduces silver consumption. In 0BB technology, glue is directly used to fix the solder ribbon on the surface of the cell, which not only saves the welding process, but also reduces the impact of welding temperature on cell performance. However, since the solder ribbon itself is opaque, it has a lot of obstruction on the surface of the cell, which seriously affects the power generation efficiency of the component. During the lamination process, greater pressure and glue impact will cause the solder ribbon on the cell to shift, which in turn increases its ohmic contact resistance with the auxiliary strip. In addition, the encapsulation film will penetrate into the interface between the solder ribbon and the auxiliary strip or the solder ribbon and the battery after thermal melting, further leading to poor contact and reducing the power of the component. Utility Model Content

[0003] Based on this, it is necessary to provide a battery string. The battery string of the utility model has the advantages of small square resistance and high light transmittance, which can reduce light reflection and avoid the shielding of silicon wafers by welding strips, and is conducive to improving the power of photovoltaic modules.

[0004] An embodiment of the present application provides a battery string.

[0005] A battery string comprises a plurality of battery cells, a metal interconnection bar and a transparent conductive film, wherein the transparent conductive film comprises a transparent base layer prepared from a transparent polymer base material and metal nanowires, wherein the metal nanowires are connected to the surface of the transparent base layer, wherein a plurality of battery cells are placed in sequence, wherein the positive and negative electrodes of adjacent battery cells are connected via the metal interconnection bar, wherein the light-receiving surface and the backlight surface of the battery cell are respectively connected to the transparent conductive film, wherein the metal nanowires on the transparent conductive film are electrically connected to the secondary grid lines on the battery cell, and the ends of the metal nanowires are also connected to the metal interconnection bar.

[0006] In some embodiments, the metal interconnection strip is connected to the edge of the battery cell by a connector.

[0007] In some embodiments, the connecting member is an adhesive, and the adhesive includes one or more of conductive glue, conductive tape and solder paste.

[0008] In some embodiments, the length of the metal interconnection strip is 2 mm to 10 mm.

[0009] In some of the embodiments, the number of the metal interconnection bars connected to the same battery cell is 2 to 30.

[0010] In some embodiments, the metal interconnection strip is a metal wire with a solder coated on the surface, the metal wire is a copper wire, a silver wire, an aluminum wire or an alloy wire thereof, and the solder is a tin-based solder.

[0011] In some of the embodiments, the diameter of the metal interconnection strip is 0.01 mm to 0.5 mm.

[0012] In some of the embodiments, the light transmittance of the transparent conductive film is 85% to 99.5%.

[0013] In some embodiments, the metal nanowires are silver nanowires, copper nanowires, gold nanowires or aluminum nanowires;

[0014] and / or, the geometric shape of the metal nanowire is a linear rod structure, a circular ring structure or a polygonal structure;

[0015] And / or, the diameter of the metal nanowire is 1 nm to 200 nm.

[0016] An embodiment of the present application also provides a photovoltaic module.

[0017] A photovoltaic assembly comprises the battery string.

[0018] The above-mentioned battery string no longer uses metal interconnection bars to connect the entire surface of the battery cell, but only connects at the edge of the battery cell, completely removing the shielding of the metal interconnection bars on the battery, and at the same time using a transparent conductive film with low square resistance, high transparency and good flexibility to collect the current on the battery surface, which can not only reduce the power loss caused by the resistance thermal effect, but also improve the flexibility of the battery string and reduce the occurrence of hidden cracks. In addition, during the lamination process, the adhesive film no longer directly contacts the battery surface after thermal melting, completely avoiding the problem of poor ohmic contact caused by the spread of glue, and the curing of the adhesive film after lamination can further compact the transparent conductive film and the battery cell, thereby obtaining an ideal ohmic contact.

[0019] In summary, the battery cell of the present application has the following beneficial effects:

[0020] (1) This application uses a transparent conductive film containing metal nanowires to replace traditional solder strips, which has the advantages of small square resistance and high light transmittance. It can reduce light reflection and avoid metal interconnection strips blocking the silicon wafer, which is beneficial to improving the power of photovoltaic modules.

[0021] (2) The transparent conductive film containing metal nanowires used in the present application can be used to prevent the adhesive film from melting and filling the gap between the metal nanowires and the auxiliary wires during the lamination process, thereby improving the ohmic defect rate.

[0022] (3) The transparent conductive film used in the present application has good flexibility and has a good protective buffering effect on the battery, which can further reduce the probability of hidden cracks in the battery cell.

[0023] (4) The present application eliminates the process of preparing the battery main grid and stringing the batteries together in the traditional technology, which is helpful to reduce the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0025] In order to more completely understand the present application and its beneficial effects, the following description will be made in conjunction with the accompanying drawings. In the following description, the same reference numerals represent the same parts.

[0026] Figure 1 This is a schematic diagram of a battery string according to an embodiment of the utility model;

[0027] Figure 2 A schematic diagram of a transparent conductive film of a battery string according to an embodiment of the utility model;

[0028] Figure 3 It is a partial structural schematic diagram of a battery string described in an embodiment of the utility model.

[0029] Description of Reference Numerals

[0030] 10. Battery string; 100. Battery cell; 101. Subgrid line; 200. Metal interconnection strip; 300. Transparent conductive film; 310. Transparent substrate layer; 320. Metal nanowire. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] In the present disclosure, the terms "light-receiving surface" and "backlight surface" are used only to distinguish the locations of two opposite surfaces of the battery substrate. In actual working conditions, the "light-receiving surface" is the surface of the battery substrate that mainly receives light, but the "backlight surface" does not necessarily not receive light. On the contrary, due to the existence of diffusely reflected light, the "backlight surface" can also receive light in actual working conditions.

[0038] The embodiment of the present application provides a battery string 10 to solve at least one of the following problems: the solder strip in the conventional technology has a lot of shielding on the surface of the battery cell, which seriously affects the power generation efficiency of the module; during the lamination process, the greater pressure and glue impact will cause the solder strip on the battery cell to deviate, thereby increasing the ohmic contact resistance between it and the auxiliary strip; and the packaging film will penetrate into the interface between the solder strip and the auxiliary strip or the solder strip and the battery after thermal melting, further causing poor contact and reducing the power of the module. The battery string 10 will be described below in conjunction with the accompanying drawings.

[0039] The battery string 10 provided in the embodiment of the present application is exemplary, see Figure 1 As shown, Figure 1 The schematic diagram of the structure of the battery string 10 provided in the embodiment of the present application is as follows. The battery string 10 of the present application has the advantages of small square resistance and high light transmittance.

[0040] In order to more clearly illustrate the structure of the battery string 10, the battery string 10 will be described below with reference to the accompanying drawings. Figure 1 As shown, Figure 1 A schematic diagram of the structure of a battery string 10 provided in an embodiment of the present application.

[0041] A battery string 10 includes a plurality of battery cells 100, a metal interconnection bar 200 and a transparent conductive film 300. Figure 2 As shown, Figure 2 FIG. 3 is a schematic diagram of a transparent conductive film 300 of a battery string 10 according to an embodiment of the present invention. The transparent conductive film 300 includes a transparent substrate layer 310 made of a transparent polymer substrate material and metal nanowires 320. Figure 2The right side of the figure is an enlarged view of the metal nanowire 320. The metal nanowire 320 is connected to the surface of the transparent substrate layer 310 by printing or deposition. Multiple battery cells 100 are placed in sequence, and the positive and negative electrodes of adjacent battery cells 100 are connected by metal interconnection bars 200. The light-receiving surface and the backlight surface of the battery cell 100 are respectively connected to transparent conductive films 300. The metal nanowire 320 on the transparent conductive film 300 is electrically connected to the secondary grid line 101 on the battery cell 100. The end of the metal nanowire 320 is also connected to the metal interconnection bar 200.

[0042] The battery string 10 no longer uses the metal interconnection bar 200 to connect the entire surface of the battery cell 100, but only connects at the edge of the battery cell 100, completely removing the shielding of the metal interconnection bar 200 on the battery, and at the same time uses the transparent conductive film 300 with low square resistance, high transparency and good flexibility to collect the current on the battery surface, which can not only reduce the power loss caused by the resistance thermal effect, but also improve the flexibility of the battery string 10 and reduce the occurrence of hidden cracks. In addition, during the lamination process, the adhesive film no longer directly contacts the battery surface after thermal melting, completely avoiding the problem of poor ohmic contact caused by the spread of glue, and the curing of the adhesive film after lamination can further compact the transparent conductive film 300 and the battery cell 100, thereby obtaining an ideal ohmic contact.

[0043] In some embodiments, the metal interconnection bar 200 is connected to the edge of the battery cell 100 by a connector. That is to say, the metal interconnection bar 200 of the present application does not cover the entire width of the battery cell 100, but extends to a portion of the battery cell 100, see Figure 3 As shown, Figure 3 It is a partial structural diagram of a battery string 10 according to an embodiment of the present invention. For example, the end of the metal interconnection bar 200 extends to a length of 2 mm to 3 mm on the battery cell 100, thereby preventing the metal interconnection bar 200 from blocking the battery cell 100.

[0044] In some embodiments, the metal nanowires 320 on the transparent conductive film 300 are perpendicular to the secondary grid lines 101 on the cell 100 .

[0045] In some embodiments, the metal interconnection strip 200 may be a solder ribbon.

[0046] In some of these embodiments, the connecting member is an adhesive.

[0047] In some embodiments, the adhesive includes one or more of conductive glue, conductive tape and solder paste.

[0048] In some embodiments, the length of the metal interconnection strip 200 is 2 mm to 10 mm.

[0049] In some embodiments, the number of metal interconnection bars 200 connected to the same battery cell 100 is 2 to 30.

[0050] In some embodiments, the metal interconnection bar 200 is a metal wire with solder coated on its surface.

[0051] In some embodiments, the metal wire is a copper wire, a silver wire, an aluminum wire, or an alloy thereof.

[0052] In some embodiments, the solder is a tin-based solder.

[0053] In some embodiments, the diameter of the metal interconnection bar 200 is 0.01 mm to 0.5 mm.

[0054] In some embodiments, the light transmittance of the transparent conductive film 300 is 85%-99.5%.

[0055] In some embodiments, the metal nanowire 320 is a silver nanowire, a copper nanowire, a gold nanowire, or an aluminum nanowire.

[0056] In some embodiments, the metal nanowire 320 has a geometric shape of a linear rod structure, a circular ring structure, or an arbitrary polygonal structure.

[0057] In the present application, the metal nanowires 320 are only printed or deposited on one surface of the transparent base layer 310 and are not embedded inside thereof.

[0058] In some embodiments, the material of the transparent base layer 310 includes, but is not limited to, polyethyleneimine, polyimide, polyetherimide, polyethylene terephthalate, polycarbonate, polyvinyl fluoride, and polyvinylidene fluoride.

[0059] In some embodiments, the diameter of the metal nanowire 320 is 1 nm to 200 nm.

[0060] The metal nanowire 320 is a one-dimensional nanomaterial that has the small size effect and high light transmittance characteristics of nanomaterials, as well as excellent electrical conductivity, thermal conductivity and flexibility, and the material cost is controllable. The present application uses a transparent conductive film containing metal nanowires 320 to improve the problems of traditional metal interconnection bars 200 or metal wires blocking the battery power generation area, the displacement of the metal interconnection bars 200 during the lamination process, and poor ohmic contact caused by the melting and filling of the adhesive film, and is highly innovative.

[0061] It should be noted that, in the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the distribution of optional numerical values ​​within the numerical interval is deemed to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0062] An embodiment of the present application also provides a photovoltaic module.

[0063] A photovoltaic module includes a battery string 10.

[0064] An embodiment of the present application also provides a method for preparing a photovoltaic module.

[0065] The preparation method of photovoltaic modules mainly includes the following steps:

[0066] 1) The front panel, front film, battery string 10, back film, back panel and other packaging materials are sequentially laid by stacking method. The front film and back film can be EVA, EPE or POE respectively. For example, the front panel is front photovoltaic glass, and the back panel is back photovoltaic glass.

[0067] 2) The lead wires of the metal interconnection bars 200 at both ends of the battery string 10 are connected and fixed to the bus bar and an EL test is performed.

[0068] 3) Fix the stacked packaging materials by lamination, compact the contact between the transparent conductive film 300 and the secondary gate line, and perform EL test.

[0069] 4) After the steps of framing, gluing, curing, etc., the photovoltaic module is obtained.

[0070] 5) Finally, the photovoltaic modules are subjected to performance tests.

[0071] Photovoltaic modules are prepared according to the above method. Different implementation methods are shown in Table 1. Test data of each photovoltaic module is shown in Table 1.

[0072] Table 1

[0073]

[0074] Note: EL stands for electroluminescence. Under normal circumstances, the component will emit light after power is turned on. The appearance of local EL shadows indicates that there is a poor contact at that location.

[0075] Combining Example 1, Comparative Examples 1 and 2, it can be seen that the use of the transparent conductive film 300 provided by the present application can significantly improve the power of the component without EL shadows; when the transparent base layer 310 is replaced with EVA, the EVA has a high fluidity after thermal melting, which will impact or penetrate the metal nanowires 320, resulting in local poor contact, thereby causing local EL shadows and a decrease in power; and when the transparent base layer 310 is not used, the packaging material POE of the component itself will also impact or penetrate the metal nanowires 320, causing local EL shadows. Therefore, the barrier effect of the transparent base layer 310 on the molten adhesive film during the lamination process is conducive to improving the EL shadow and improving the power of the component.

[0076] Combining Example 1, Comparative Examples 3 and 4, it can be seen that Comparative Examples 3 and 4 are all connected to the battery cells with metal interconnection bars 200 in a fully covered manner, while Example 1 uses a transparent conductive film 300 containing nano silver wires to replace the metal interconnection bars 200, and the power of the module is also significantly improved. This is mainly because the use of metal nanowires 320 greatly reduces the shielding of the battery cells, and the metal nanowires 320 have low impedance performance, which reduces power loss. It can be seen from Comparative Examples 3 and 4 that the transparent substrate layer 310 provided by the present application has almost no effect on the power of the module, and its light transmittance is good.

[0077] At the same time, during the batch verification process of Comparative Example 4, hidden cracks sometimes occurred in the components; however, after using the transparent conductive film 300 of the present application, the battery basically had no hidden cracks, which indicates that the good flexibility of the transparent conductive film 300 provides good protection for the battery.

[0078] In summary, the battery cell 100 of the present application has the following beneficial effects:

[0079] (1) The present application adopts a transparent conductive film 300 containing metal nanowires 320 to replace the traditional soldering tape, which has the advantages of small square resistance and high light transmittance, can reduce the reflection of light, avoid the shielding of silicon wafer by the soldering tape, and is beneficial to improving the power of photovoltaic modules.

[0080] (2) The transparent conductive film 300 containing the metal nanowires 320 used in the present application can be filled between the metal nanowires 320 and the auxiliary wires after the blocking film melts during the lamination process, thereby improving the ohmic defect rate.

[0081] (3) The transparent conductive film 300 used in the present application has good flexibility and has a good protective buffering effect on the battery, which can further reduce the probability of hidden cracks in the battery cell 100.

[0082] (4) The present application eliminates the process of preparing the battery main grid and stringing the batteries together in the traditional technology, which is helpful to reduce the production cost.

[0083] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0084] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A battery string (10), characterized in that: The invention comprises a plurality of battery cells (100), a metal interconnection bar (200) and a transparent conductive film (300), wherein the transparent conductive film (300) comprises a transparent base layer (310) prepared from a transparent polymer base material and a metal nanowire (320), wherein the metal nanowire (320) is connected to the surface of the transparent base layer (310), wherein a plurality of battery cells (100) are sequentially arranged, wherein the positive and negative electrodes of adjacent battery cells (100) are connected via the metal interconnection bar (200), wherein the light-receiving surface and the backlight surface of the battery cell (100) are respectively connected to the transparent conductive film (300), wherein the metal nanowire (320) on the transparent conductive film (300) is electrically connected to a secondary grid line (101) on the battery cell (100), and the end of the metal nanowire (320) is also connected to the metal interconnection bar (200).

2. The battery string (10) according to claim 1, characterized in that: The metal interconnection strip (200) is connected to the edge of the battery cell (100) by a connector.

3. The battery string (10) according to claim 2, characterized in that: The connecting member is an adhesive, and the adhesive includes one or more of conductive glue, conductive tape and solder paste.

4. The battery string (10) according to any one of claims 1 to 3, characterized in that: The length of the metal interconnection strip (200) is 2 mm to 10 mm.

5. The battery string (10) according to any one of claims 1 to 3, characterized in that: The number of the metal interconnection bars (200) connected to the same battery cell (100) is 2 to 30.

6. The battery string (10) according to any one of claims 1 to 3, characterized in that: The metal interconnection bar (200) is a metal wire with a solder coated on the surface, the metal wire is a copper wire, a silver wire, an aluminum wire or an alloy wire thereof, and the solder is a tin-based solder.

7. The battery string (10) according to any one of claims 1 to 3, characterized in that: The diameter of the metal interconnection strip (200) is 0.01 mm to 0.5 mm.

8. The battery string (10) according to any one of claims 1 to 3, characterized in that: The light transmittance of the transparent conductive film (300) is 85% to 99.5%.

9. The battery string (10) according to any one of claims 1 to 3, characterized in that: The metal nanowire (320) is a silver nanowire, a copper nanowire, a gold nanowire or an aluminum nanowire; And / or, the geometric shape of the metal nanowire (320) is a linear rod structure, a circular ring structure or a polygonal structure; And / or, the diameter of the metal nanowire (320) is 1 nm to 200 nm.

10. A photovoltaic module, characterized in that: A battery string (10) comprising the battery string (10) as claimed in any one of claims 1 to 9.

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