Solar cell and photovoltaic module

Abstract

The utility model relates to a solar cell and a photovoltaic assembly, the solar cell comprises a cell sheet, and the cell sheet comprises a substrate and a passivation structure layer arranged on the back surface of the substrate; a plurality of grooves are formed in the back face of the battery piece at intervals in the first direction, the substrate is exposed out of the grooves, and the grooves are formed through laser; wherein the groove width of the open grooves at the two ends of the battery piece in the first direction is larger than the groove width of the open groove in the middle part. According to the invention, the width of the slots at the two ends of the first direction on the cell is wider than the width of the slot at the middle part, so that alignment during printing is facilitated, and even if the slots and a printing pattern slightly deviate, the slurry can realize a good overprinting effect, so that good AL-Si ohmic contact is formed during silk screen sintering, and the printing quality is improved. Therefore, the battery performance and the battery yield are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic cells, in particular to a solar cell and a photovoltaic component. Background Art

[0002] At present, Passivated Emitter and Rear Cell (PERC cell) is widely used because it has significantly improved efficiency compared to conventional cells. PERC cells require the use of lasers to make grooves on the back of silicon wafers to expose the silicon substrate at the grooves, and then use screen printing to print the slurry at the grooves so that the slurry contacts the silicon substrate, thereby improving the efficiency of the cell.

[0003] In the prior art, the laser-grooved end of the back of the PERC cell cannot form a good overprinting effect with the slurry during the overprinting process, resulting in the inability to form a good AL-Si ohmic contact during screen sintering, which leads to a decrease in cell performance and ultimately results in a defective product. Utility Model Content

[0004] Based on this, it is necessary to provide a solar cell and a solar cell to address the technical problem in the prior art that the end of the laser groove on the back of the PERC cell cannot form a good overprint effect with the slurry, resulting in a decrease in cell performance.

[0005] A solar cell, comprising:

[0006] A battery cell comprises a substrate and a passivation structure layer arranged on the back side of the substrate;

[0007] The back side of the battery cell is provided with a plurality of grooves spaced apart along a first direction, the substrate is exposed from the grooves, and the grooves are opened by laser;

[0008] Wherein, the width of the grooves at the two ends of the battery cell in the first direction is greater than the width of the grooves in the middle.

[0009] In one embodiment, the grooves include a first groove, a second groove, a third groove and a fourth groove which are arranged in sequence from both ends of the battery cell to the middle of the battery cell, and the groove width of the grooves gradually decreases from the first groove to the fourth groove.

[0010] In one embodiment, the first slot, the second slot and the third slot are respectively provided at two ends of the battery cell; the number of the fourth slots is multiple; the first slot, the second slot and the third slot are respectively provided at two ends of the battery cell; the number of the fourth slots is multiple;

[0011] The first slot, the second slot, the third slot and the fourth slot are all discontinuous slots.

[0012] In one embodiment, the width of the first groove, the width of the second groove, the width of the third groove, and the width of the fourth groove decrease by 1-2 um in sequence.

[0013] In one embodiment, the width of the first slot is in the range of 31-35 um;

[0014] The width of the second slot is between 29-33 um;

[0015] The width of the third slot is between 27-31 um;

[0016] The width of the fourth slot is between 25-29 um.

[0017] In one embodiment, the groove depth is between 80-100 nm.

[0018] In one embodiment, two positioning marks are provided at both ends of the back side of the battery cell and are spaced apart along the second direction, and the positioning marks are provided between the first slot and the second slot;

[0019] Wherein, the positioning mark extends along the first direction, and the first direction is perpendicular to the second direction.

[0020] In one embodiment, each of the positioning marks includes two spaced apart positioning grooves.

[0021] In one of the embodiments, the depth of the positioning groove is between 8-10 nm.

[0022] A solar cell comprises the solar cell as described above.

[0023] Beneficial effects of the utility model:

[0024] The utility model provides a solar cell, wherein the substrate is used to absorb photoelectrons, and a passivation structure layer is arranged on the surface of the substrate to suppress light reflection on the substrate surface and improve light absorption efficiency; at the same time, it also has the function of preventing oxidation or corrosion on the substrate surface to improve the stability and life of the solar cell. Since the passivation structure layer is not conductive, it is necessary to arrange electrode grid lines on the substrate surface to collect carriers and transport the carriers to the load. By opening a plurality of grooves on the back of the cell sheet and exposing the substrate from the grooves, the slurry is printed on the grooves and contacts the substrate through the screen printing process to form grid lines. In the utility model, the groove width of the grooves at both ends of the cell sheet in the first direction is arranged to be wider than the width of the grooves in the middle part, so as to facilitate alignment during printing. Even if the grooves are slightly offset from the printed pattern, the slurry can achieve a good overprinting effect, so that a good AL-Si ohmic contact is formed during screen sintering, thereby improving the battery performance and the battery yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of a solar cell provided in one embodiment of the utility model;

[0026] Figure 2 A schematic diagram of a partially enlarged structure of a solar cell provided in one embodiment of the utility model;

[0027] Figure 3 A schematic diagram of a partially enlarged structure of a positioning mark in a solar cell provided by an embodiment of the utility model.

[0028] Reference numerals:

[0029] Battery cell 100; slot 200; first slot 210; second slot 220; third slot 230; fourth slot 240; positioning mark 250; positioning slot 251; first direction Y; second direction X. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[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] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0036] See also Figures 1 to 3 An embodiment of the utility model provides a solar cell, the solar cell comprising a cell 100, the cell 100 comprising a substrate and a passivation structure layer arranged on the back side of the substrate; a plurality of grooves 200 arranged at intervals along a first direction Y are opened on the back side of the cell 100, the substrate is exposed from the grooves 200, and the grooves 200 are opened by laser; wherein, the groove widths of the grooves 200 at the two ends of the cell 100 in the first direction Y are greater than the groove widths of the grooves 200 in the middle.

[0037] The technical solution provides a solar cell, wherein the substrate is used to absorb photoelectrons, and a passivation structure layer is arranged on the surface of the substrate to suppress light reflection on the substrate surface and improve light absorption efficiency; at the same time, it also has the function of preventing oxidation or corrosion on the substrate surface to improve the stability and life of the solar cell. Since the passivation structure layer is not conductive, it is necessary to arrange electrode grid lines on the substrate surface to collect carriers and transport the carriers to the load. By opening a plurality of grooves 200 on the back of the cell 100 and exposing the substrate from the grooves 200, the slurry is printed on the grooves 200 by the screen printing process and contacts the substrate to form grid lines. In the utility model, the groove width of the grooves 200 at both ends of the first direction Y on the cell 100 is set wider than the width of the grooves 200 in the middle part, so as to facilitate alignment during printing. Even if the grooves are slightly offset from the printed pattern, the slurry can achieve a good overprinting effect, so that a good AL-Si ohmic contact is formed during screen sintering, thereby improving the battery performance and battery yield.

[0038] It is understandable that in this embodiment, the substrate is a single crystal silicon wafer or a multi-crystalline silicon wafer. A layer of Al2O3 film is plated on the back of the silicon wafer for back passivation, and a layer of SiN film is plated on the outside of the Al2O3 film to improve the back reflectivity. Since the Al2O3 and SiN films are not conductive, the photogenerated carrier output generated by the cell 100 cannot be provided to the load, so it is necessary to use a laser to perform laser grooving on the back of the silicon wafer to expose the silicon substrate at the groove, so that the slurry can contact the silicon substrate during printing, thereby improving the efficiency of the cell 100. In this embodiment, the passivation structure layer is an Al2O3 and SiN film layer.

[0039] It should be noted that the solar cell provided in this embodiment is mainly used in PERC cells, and the solar cell is arranged on the back of the PERC cell, and is mainly used in the production of the back electric field of the PERC cell. In this embodiment, the first direction Y is the length direction or the width direction of the cell 100, and the second direction X is the direction perpendicular to the first direction Y. For example, when the first direction Y is the length direction of the cell 100, the second direction X is the width direction of the cell 100.

[0040] like Figures 1 to 3 As shown, in one embodiment, the groove 200 includes a first groove 210, a second groove 220, a third groove 230 and a fourth groove 240 which are arranged in sequence from both ends of the battery cell 100 to the middle of the battery cell 100, and the groove width of the groove 200 gradually decreases from the first groove 210 to the fourth groove 240.

[0041] It is understandable that the first slot 210, the second slot 220, the third slot 230 and the fourth slot 240 are symmetrically arranged at both ends of the battery cell 100. Since the deformation of the two ends of the screen is large under the action of the slurry during screen printing, it is easy to cause the slots 200 at both ends of the battery cell 100 to be cheap. Therefore, in this embodiment, the slot width of the first slot 210 at both ends is set to be slightly wider than the slot width of the second slot 220, even if the screen is deformed and offset, the overprinting effect of the slurry can be guaranteed. Since the deformation is smaller or even no deformation occurs toward the middle, the width of the fourth slot 240 located in the middle is set to be thinner to reduce the shading of the metal slurry, thereby improving the battery performance.

[0042] like Figures 1 to 3 As shown, in one embodiment, a first slot 210, a second slot 220 and a third slot 230 are respectively provided at both ends of the cell 100; the number of the fourth slot 240 is multiple; the first slot 210, the second slot 220, the third slot 230 and the fourth slot 240 are all intermittently provided slots. For the first slot 210, the second slot 220 and the third slot 240 with a wider slot width, only one is provided at each end of the cell 100, so that while ensuring the overprinting effect, the light shielding area of ​​the metal paste on the cell 100 is reduced, thereby improving the performance of the cell 100. Since aluminum oxide and silicon nitride are non-conductive substances, before printing the back electric field, a part of aluminum oxide and silicon nitride needs to be removed to achieve electrical contact between the back field and the silicon substrate. The laser grooving process uses a laser beam to directly bombard the back passivation layer structure according to a certain pattern. Back laser grooving will cause irreversible damage to the silicon wafer. Therefore, the above-mentioned first groove 210, second groove 220, third groove 230, and fourth groove 240 are set to be intermittent, which is beneficial to reduce damage to the silicon wafer.

[0043] like Figures 1 to 3 As shown, in one embodiment, the width of the first slot 210, the width of the second slot 220, the width of the third slot 230, and the width of the fourth slot 240 decrease by 1-2um in sequence. Specifically, the width range of the first slot 210 is between 31-35um; the width of the second slot 220 is between 29-33um; the width of the third slot 230 is between 27-31um; and the width of the fourth slot 240 is between 25-29um. For example, the width of the first slot 210 can be 33um, the width of the second slot 220 can be 31um, the width of the third slot 230 can be 29um, and the width of the fourth slot 240 can be 27um. Of course, the width of the first slot 210 may be set to 35 um, the width of the second slot 220 may be set to 33 um, the width of the third slot 230 may be set to 31 um, and the width of the fourth slot 240 may be set to 25 um.

[0044] like Figures 1 to 3 As shown, in one embodiment, the groove depth of the groove 200 is between 80-100 nm. The groove depth of the groove 200 is set between 80-100 nm so that the passivation structure layer on the battery cell 100 can be completely removed at the groove 200 to completely expose the substrate, thereby ensuring that the overprinted slurry can completely contact the substrate.

[0045] like Figure 1 As shown, in one embodiment, two positioning marks 250 are arranged at intervals along the second direction X at both ends of the back of the battery cell 100, and the positioning mark 250 is arranged between the first slot 210 and the second slot 220; wherein, the positioning mark 250 extends along the first direction Y, and the first direction Y is perpendicular to the second direction X. By setting the positioning mark 250 between the first slot 210 and the second slot 220, the aluminum grid line printed along the second direction X can be positioned. Specifically, through the positioning mark 250, it is possible to clearly see whether the aluminum grid line printed along the second direction X is offset as a whole, so as to facilitate micro-adjustment of the screen during printing, thereby ensuring the overprinting effect and improving the battery performance.

[0046] like Figure 3As shown, in one embodiment, each positioning mark 250 includes two spaced positioning grooves 251. By setting each positioning mark 250 as two spaced positioning grooves 251, the positioning mark is made more obvious, thereby facilitating positioning. In this embodiment, the positioning groove 251 is actually a shallow mark opened by laser. Specifically, the groove depth of the positioning groove 251 is between 8-10nm. The groove depth of the positioning groove 251 is set to between 8-10nm, so that the positioning mark 250 can be identified by the naked eye, ensuring that the passivation structure layer is not damaged, thereby ensuring the reflective performance of the battery cell 100, and then ensuring the efficiency of the battery cell 100.

[0047] Further, in a battery cell 100, two positioning marks 250 spaced apart along the second direction X are respectively arranged at both ends along the first direction Y, and each positioning mark includes two spaced apart positioning grooves 251. That is, eight positioning grooves 251 are arranged on a battery cell.

[0048] The utility model also provides a photovoltaic module, which includes the above solar cell. By using the above solar cell in the photovoltaic module, the groove width of the grooves 200 at both ends of the first direction Y on the battery sheet 100 is set wider than the width of the grooves 200 in the middle, so as to facilitate alignment during printing, even if the grooves and the printed pattern are slightly offset, the slurry can achieve a good overprinting effect, so that a good Al-Si ohmic contact is formed during the sintering of the screen, thereby improving the battery performance and battery yield.

[0049] 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.

[0050] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which 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 solar cell, characterized in that: The solar cell comprises: A battery cell comprises a substrate and a passivation structure layer arranged on the back side of the substrate; The back side of the battery cell is provided with a plurality of grooves spaced apart along a first direction, the substrate is exposed from the grooves, and the grooves are opened by laser; Wherein, the width of the grooves at the two ends of the battery cell in the first direction is greater than the width of the grooves in the middle.

2. The solar cell according to claim 1, characterized in that The grooves include a first groove, a second groove, a third groove and a fourth groove which are sequentially arranged from both ends of the battery cell to the middle of the battery cell, and the groove width of the grooves gradually decreases from the first groove to the fourth groove.

3. The solar cell according to claim 2, characterized in that: The first slot, the second slot and the third slot are respectively provided at two ends of the battery cell; the number of the fourth slots is multiple; The first slot, the second slot, the third slot and the fourth slot are all discontinuous slots.

4. The solar cell according to claim 2, characterized in that: The width of the first groove, the width of the second groove, the width of the third groove, and the width of the fourth groove decrease by 1-2 um in sequence.

5. The solar cell according to claim 2, characterized in that: The width of the first slot is in the range of 31-35um; The width of the second slot is between 29-33 um; The width of the third slot is between 27-31 um; The width of the fourth slot is between 25-29 um.

6. The solar cell according to any one of claims 1 to 5, characterized in that: The groove depth is between 80-100 nm.

7. The solar cell according to any one of claims 2 to 5, characterized in that: Two positioning marks are arranged at intervals along the second direction at both ends of the back side of the battery sheet, and the positioning marks are arranged between the first slot and the second slot; Wherein, the positioning mark extends along the first direction, and the first direction is perpendicular to the second direction.

8. The solar cell according to claim 7, characterized in that: Each of the positioning marks includes two spaced positioning grooves.

9. The solar cell according to claim 8, characterized in that: The depth of the positioning groove is between 8-10 nm.

10. A photovoltaic module, characterized in that: The photovoltaic module comprises the solar cell according to any one of claims 1 to 9.

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