Solar cell grid line, solar cell and solar cell

Abstract

The utility model discloses a solar cell grid line, a solar cell and a solar cell, and relates to the technical field of solar cells, the cell grid line comprises a plurality of rectangular grid line layers, each rectangular grid line layer comprises a rectangular frame, a main grid line and a fine grid line, the main grid line and the fine grid line are arranged in the rectangular frame, and the main grid line and the fine grid line are arranged in the rectangular frame. The fine grid lines are parallel to one another, and the main grid lines are perpendicular to the fine grid lines; the plurality of rectangular grid line layers are printed on the surface of the positive electrode of the solar cell in parallel. The plurality of rectangular grid line layers are parallel to each other, the length of the grid lines is infinitely close to that of the battery piece, the grid line layers in the rectangular frame are printed on the surface of the battery piece in parallel, and in the process of laser enhanced contact optimization of an LECO machine table, a probe row of the LECO machine table is vertically pressed, so that bias voltage can be applied to all grid line patterns at the same time; and the efficiency of applying the voltage to the grid line pattern of the battery piece by the LECO machine is improved.

Description

Technical Field

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

[0002] The LECO process involves using high-intensity laser pulses at a constant reverse voltage of more than 10V on the front of the solar cell. The resulting current of several amperes greatly reduces the contact resistivity between the semiconductor and the metal electrode. In the field of solar cell technology, LECO machines are often used to perform laser-enhanced contact optimization on sintered cells.

[0003] When the LECO machine is performing enhanced contact optimization on the battery cell, the laser and bias voltage need to work simultaneously. In the prior art, the grid line graphics are often designed into multiple independent graphics, such as Chinese patent CN111641388B - A method for testing metal contact composite value and solar cell. The disclosed graphics are divided into multiple independent small areas, and a bias voltage is applied to one of the areas, while no current passes through the other graphics. This causes the user to apply bias voltage to the independent small areas multiple times during the laser enhanced contact optimization process on the LECO machine, resulting in a decrease in the efficiency of applying voltage to the grid line graphics of the battery cell. Utility Model Content

[0004] In view of this, the utility model provides a solar cell grid line, a solar cell and a solar cell to solve the above technical problems.

[0005] To achieve the above object, the utility model provides the following technical solution: a solar cell grid line, including a plurality of rectangular grid line layers, wherein the rectangular grid line layer includes a rectangular frame, a main grid line and a thin grid line, wherein:

[0006] The main grid lines and the thin grid lines are within the rectangular frame, a plurality of the thin grid lines are parallel to each other, and the main grid lines are perpendicular to the thin grid lines;

[0007] Several rectangular grid line layers are printed in parallel on the positive electrode surface of the solar cell.

[0008] Furthermore, the length of the rectangular grid line layer is infinitely close to the length of the solar cell.

[0009] Furthermore, the line widths of the plurality of fine gate lines are the same, and the spacings between the plurality of fine gate lines are different.

[0010] In a second aspect, the utility model provides a solar cell, comprising a first cell and a second cell, wherein a solar cell grid line as described above is printed on a surface of the first cell, and the second cell is arranged on a side away from the first cell.

[0011] Furthermore, the solar cell is made of silicon nitride.

[0012] In a third aspect, the utility model provides a solar cell, including a cell grid line, a cell and an electrode, wherein:

[0013] The electrode comprises a front electrode and a back electrode, and the battery cell comprises a first battery cell and a second battery cell;

[0014] The front electrode is connected to the first battery cell, the back electrode is connected to the second battery cell, and the battery cell grid line is printed on the first battery cell.

[0015] Furthermore, it also includes a passivation layer, and the upper surface of the passivation layer is connected to the first battery cell.

[0016] Furthermore, it also includes a contact layer, and the upper surface of the contact layer is connected to the passivation layer.

[0017] Furthermore, it also includes an N-type silicon wafer and an N+ layer, and an anti-reflection coating is provided between the N-type silicon wafer and the N+ layer, wherein:

[0018] The upper surface of the N-type silicon wafer is connected to the lower surface of the contact layer, and the lower surface of the N-type silicon wafer is connected to the anti-reflection coating.

[0019] Furthermore, the upper surface of the N+ layer is connected to the anti-reflection coating, and the lower surface of the N+ layer is connected to the second battery cell.

[0020] The beneficial effects of adopting the technical solution of this application are as follows:

[0021] The utility model provides a solar cell grid line, a solar cell and a solar cell, which are improvements made on the grid line pattern. The solar cell grid line provided by the present application adopts the arrangement of areas with different metal proportions in a disrupted manner, and uses a closed rectangular frame as isolation on the outside of the grid line pattern, which can reduce the test error. On the other hand, the length of the grid line is infinitely close to the cell, and the grid line layer in the rectangular frame is printed in parallel on the surface of the cell. In the process of laser enhanced basic optimization by a LECO machine, the probe row of the LECO machine is vertically pressed to apply bias to all the grid line patterns at the same time, without the need to apply bias to grid line areas with different line widths respectively, thereby improving the efficiency of the LECO machine in applying voltage to the grid line pattern of the cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the drawings required for use in the implementation mode will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a partial structural schematic diagram of a solar cell grid line in an embodiment of the present application;

[0024] Figure 2 This is a schematic diagram of the overall structure of a solar cell grid line in an embodiment of the present application;

[0025] Figure 3 This is a schematic diagram of the overall structure of a solar cell in an embodiment of the present application.

[0026] The reference numerals are as follows:

[0027] 1. Front electrode; 2. Cell grid line; 201. Rectangular frame; 202. Main grid line; 203. Fine grid line; 3. First cell; 4. Passivation layer; 5. Contact layer; 6. N-type silicon wafer; 7. Anti-reflective coating; 8. N+ layer; 9. Second cell; 10. Back electrode. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the utility model clearer, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model for which protection is sought, but merely represents the selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0029] Laser-enhanced contact optimization (LECO) is a technology that irradiates high-intensity lasers on the cell and applies a deflection voltage of 10V or more, thereby generating a local current of several amperes, significantly reducing the contact resistance between the metal and the semiconductor, thereby improving the fill factor.

[0030] Crystalline silicon high-efficiency cells are solar cells made of monocrystalline silicon or polycrystalline silicon materials, also known as silicon-based solar cells. Crystalline silicon high-efficiency cells are one of the most widely used solar cells on the market, with advantages such as high efficiency, stability and long life.

[0031] The working principle of crystalline silicon high-efficiency cells is to use the photovoltaic effect to convert sunlight into electrical energy. When sunlight shines on the surface of crystalline silicon cells, photons will excite electrons in silicon, causing them to jump and generate current under the action of the electric field. In this way, light energy is converted into electrical energy, realizing the utilization of solar energy.

[0032] The present application embodiment provides a solar cell grid line, such as Figure 1 As shown, it includes several rectangular grid line layers, and the rectangular grid line layer includes a rectangular frame 201, a main grid line 202 and a thin grid line 203, wherein:

[0033] The main grid lines 202 and the fine grid lines 203 are within the rectangular frame 201, a plurality of the fine grid lines 203 are parallel to each other, and the main grid lines 202 are perpendicular to the fine grid lines 203;

[0034] Specifically, in the embodiment of the present application, the thin grid lines 203 are generally made of metal materials, including silver, aluminum, copper, etc. These metal materials have good electrical conductivity and mechanical properties, and are suitable for the thin grid line 203 structure in the solar cell.

[0035] Specifically, the closed rectangular frame 201 can be isolated to reduce the interference of other printed patterns on the same silicon wafer;

[0036] In the embodiment of the present application, the line widths of the fine grid lines 203 are all the same. After printing with the same line width, the actual line widths are basically the same and only need to be tested once, which can reduce the testing process. If different line widths are used, the actual line width of each printing area needs to be tested.

[0037] The metal fine grid lines 203 play an important role in solar cells, and are used to collect current and reduce the shadow effect on the surface of the cell, thereby improving the photoelectric conversion efficiency of the solar cell. The metal fine grid lines 203 are usually prepared by processes such as photolithography, evaporation, and printing to form a fine line structure on the electrode.

[0038] like Figure 2 As shown, several rectangular grid line layers are printed in parallel on the positive electrode surface of the solar cell.

[0039] Specifically, the function of printing the fine grid lines 203 on the surface of the cell is to enhance the current output efficiency of the cell. The fine grid lines 203 are conductive lines, usually made of conductive materials such as silver or aluminum, and printed on the surface of the cell. These fine grid lines 203 can help electrons flow inside the cell and increase the efficiency of converting light energy into electrical energy.

[0040] Further, in a preferred embodiment of the present application, Figure 2 As shown, the length of the rectangular grid line layer is infinitely close to the length of the solar cell.

[0041] Furthermore, in a preferred embodiment of the present application, the line widths of the plurality of fine gate lines 203 are the same, and the intervals between the plurality of fine gate lines 203 are different.

[0042] In the embodiment of the present application, the metal proportion of the gate lines is changed by changing the spacing between the fine gate lines 203. Specifically, the smaller the spacing between the fine gate lines 203, the larger the metal contact area.

[0043] In the second aspect, the utility model provides a solar cell, which includes a first cell 3 and a second cell 9, wherein the surface of the first cell 3 is printed with a solar cell grid line as described above, and the second cell 9 is arranged on a side away from the first cell 3.

[0044] Furthermore, in a preferred embodiment of the present application, the solar cell is made of silicon nitride.

[0045] Specifically, the cell is the main component of the solar cell and is located on the surface of the solar panel. The cell is composed of multiple silicon crystals, which generate current when exposed to light and convert solar energy into electrical energy. Therefore, the cell is the core component of the solar cell and plays a key role in converting light energy into electrical energy.

[0046] In a third aspect, the utility model provides a solar cell, such as Figure 3 As shown, it includes a cell grid line 2, a cell and an electrode, wherein:

[0047] The electrode comprises a front electrode 1 and a back electrode 10, and the battery cell comprises a first battery cell 3 and a second battery cell 9;

[0048] The front electrode 1 is connected to the first battery cell 3 , the back electrode 10 is connected to the second battery cell 9 , and the battery cell grid line 2 is printed on the first battery cell 3 .

[0049] Furthermore, in a preferred embodiment of the present application, a passivation layer 4 is also included, and the upper surface of the passivation layer 4 is connected to the first battery cell 3 .

[0050] Specifically, the passivation layer 4 is an aluminum oxide film, and the main functions of the aluminum oxide film are to improve the light absorption efficiency of the solar cell, reflect light, and protect the cell from the influence of the external environment.

[0051] Furthermore, in a preferred embodiment of the present application, a contact layer 5 is further included, and an upper surface of the contact layer 5 is connected to the passivation layer 4 .

[0052] Furthermore, in a preferred embodiment of the present application, it also includes an N-type silicon wafer 6 and an N+ layer 8, and an anti-reflection coating 7 is provided between the N-type silicon wafer 6 and the N+ layer 8, wherein:

[0053] The upper surface of the N-type silicon wafer 6 is connected to the lower surface of the contact layer 5 , and the lower surface of the N-type silicon wafer 6 is connected to the anti-reflection coating 7 .

[0054] In the embodiment of the present application, the N-type silicon wafer 6 generally refers to N-type silicon, which is formed by doping impurities (such as phosphorus or arsenic) into the silicon wafer, so that it has additional free electrons, thereby forming an N-type semiconductor. The N-type silicon wafer 6 has the characteristics of electron enrichment and is mainly responsible for the transport of electrons and the collection of charges. In a solar cell, the N-type silicon wafer 6 is combined with the N+ layer 8 to form a PN structure, which uses the combination of photogenerated electrons and holes to generate current and realize photoelectric conversion.

[0055] Furthermore, in a preferred embodiment of the present application, the upper surface of the N+ layer 8 is connected to the anti-reflection coating 7 , and the lower surface of the N+ layer 8 is connected to the second battery cell 9 .

[0056] In the embodiment of the present application, the N+ layer 8 may also be referred to as a P+ contact layer, also referred to as a P+ contact electrode. The P+ contact layer refers to a highly doped P+ region formed on the surface of a P-type silicon wafer, usually formed by processes such as diffusion or ion implantation. The main function of this P+ contact layer is to reduce resistance and improve charge collection efficiency, thereby improving the performance of the solar cell. The P+ contact layer is usually combined with the N+ contact layer of the N-type silicon wafer 6 to form a PN structure of the solar cell to achieve photoelectric conversion.

[0057] In one use scenario of an embodiment of the present application, a method for testing the metallization contact recombination current of a solar cell specifically includes the following steps:

[0058] Printing fine grid lines 203 on the non-test surface of the cell;

[0059] Print at least two grid line patterns with different metal proportions on the surface of the cell to be tested, and sinter them;

[0060] After sintering, the cells are passed through a LECO machine for laser-enhanced contact optimization;

[0061] Specifically, in the present invention, the LECO paste of the solar cell is different from the conventional silver paste and silver-aluminum paste. The LECO paste cannot form contact after being sintered in a sintering furnace alone, resulting in very low electrical properties FF and Isc. After being sintered in a LECO machine, better contact is formed, and FF and Isc return to normal.

[0062] The total dark state saturation current density values ​​corresponding to the gate line patterns with different metal proportions were tested respectively;

[0063] Specifically, the total dark state saturation current density value refers to the value when the current density of the photodiode or solar cell reaches the saturation state under illumination conditions. Under illumination conditions, the photodiode or solar cell will generate current, and when the illumination is strong enough, the current density will reach a stable maximum value, that is, the saturation current density value.

[0064] Collecting data of different metal proportions and total dark state saturation current density values ​​corresponding to the grid line patterns of different metal proportions, and drawing a scatter plot according to the total dark state saturation current density values ​​corresponding to the grid line patterns to obtain the slope of the linear function;

[0065] The metal contact recombination value is calculated based on the slope of the linear function and the solar cell recombination model.

[0066] Furthermore, in a preferred embodiment of the present application, at least two grid line patterns with different metal proportions are printed on the surface to be tested of the battery cell and are randomly distributed, and the different metal proportions are achieved by changing the grid line spacing by using the same line width.

[0067] Furthermore, in a preferred embodiment of the present application, the dark current test function in the battery efficiency test equipment of Sinton Company is used to measure the current density of the battery in the dark state, that is, the dark state current density. During this process, the battery cell to be tested is facing up and the battery non-to-be-tested surface is facing down, so that the non-to-be-tested surface of the battery can be fully contacted with the test bench, and the test probe can be in contact with the main grid line 202 of the grid line pattern on the surface of the battery cell to be tested.

[0068] The embodiment of the utility model simplifies the test process by changing the spacing between the gate lines.

[0069] In the embodiments of the present application, the current test scheme is optimized and applicable to silver-aluminum paste and LECO paste to isolate and disrupt the patterns, reduce interference between the substrate itself and different areas, accurately evaluate the composite current of the metal / semiconductor contact, use the same line width, change the gate line spacing to change the metal ratio, and thus simplify the test process.

[0070] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the above is a clear and complete description of the technical solutions in the embodiments of the utility model in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0071] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0072] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0073] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0074] The above contents are merely examples and explanations of the structure of the utility model. The technicians in the technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the utility model or exceed the scope defined in the claims, they should all fall within the protection scope of the utility model.

Claims

1. A solar cell grid line, characterized in that: It comprises a plurality of rectangular grid line layers, wherein the rectangular grid line layers comprise a rectangular frame, a main grid line and a thin grid line, wherein: The main grid lines and the thin grid lines are within the rectangular frame, a plurality of the thin grid lines are parallel to each other, and the main grid lines are perpendicular to the thin grid lines; Several rectangular grid line layers are printed in parallel on the surface of the solar cell.

2. A solar cell grid line according to claim 1, characterized in that: The length of the rectangular grid line layer is infinitely close to the length of the solar cell.

3. The solar cell grid line according to claim 1, characterized in that: The line widths of the plurality of fine gate lines are the same, and the spacings between the plurality of fine gate lines are different.

4. A solar cell, characterized in that: The solar cell comprises a first cell and a second cell. The surface of the first cell is printed with a solar cell grid line as claimed in claim 1 or 2. The second cell is arranged on a side away from the first cell.

5. A solar cell according to claim 4, characterized in that: The solar cell is made of silicon nitride.

6. A solar cell, characterized in that: The invention comprises the battery cell grid line, battery cell and electrode as claimed in claim 1 or 2, wherein: The electrode comprises a front electrode and a back electrode, the battery cell comprises a first battery cell and a second battery cell, a battery cell grid line is printed on a surface of the first battery cell, and the second battery cell is arranged on a side away from the first battery cell; The front electrode is connected to the first battery cell, the back electrode is connected to the second battery cell, and the battery cell grid line is printed on the first battery cell.

7. A solar cell according to claim 6, characterized in that: It also includes a passivation layer, the upper surface of which is connected to the first battery cell.

8. A solar cell according to claim 7, characterized in that: A contact layer is also included, wherein the upper surface of the contact layer is connected to the passivation layer.

9. A solar cell according to claim 8, characterized in that: It also includes an N-type silicon wafer and an N+ layer, and an anti-reflection coating is provided between the N-type silicon wafer and the N+ layer, wherein: The upper surface of the N-type silicon wafer is connected to the lower surface of the contact layer, and the lower surface of the N-type silicon wafer is connected to the anti-reflection coating.

10. A solar cell according to claim 9, characterized in that: The upper surface of the N+ layer is connected to the anti-reflection coating, and the lower surface of the N+ layer is connected to the second battery cell.

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