Electrode structure for a bc battery

Abstract

This invention discloses an electrode structure for a BC battery, relating to the field of battery technology. The electrode structure comprises n positive electrode main grids and n-1 negative electrode main grids, with one negative electrode main grid located between two positive electrode main grids. Each positive electrode main grid has m sets of positive sub-grids, and each negative electrode main grid has m sets of negative sub-grids. Adjacent sets of positive sub-grids are located on opposite sides of a positive electrode main grid, and adjacent sets of negative sub-grids are located on opposite sides of a negative electrode main grid. A set of negative sub-grids is located between two adjacent positive sub-grids on the same side. n and m are both positive integers not less than 2. The positive and negative electrode sub-grids correspond to multiple parallel designs for the P / N regions, with each P / N region being 15-24 mm long and 10-18 mm wide, and adjacent P / N regions spaced 2-4 mm apart. The number of P / N regions on the back side is 20-60, maintaining the overall electrode printing area of ​​a single PN region and effectively solving the problem of printing misalignment.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to an electrode structure for a BC battery. Background Technology

[0002] The unique performance of IBC (Internal Bundle Cell) batteries lies in their absence of grid lines obstructing the front surface; all emitters are located on the back of the battery, reducing the amount of light shading from the front metal. This novel battery structure places both positive and negative electrodes on the back, where electrons and holes are separated and collected separately through the positive and negative electrodes. Existing IBC battery electrodes are as follows... Figure 1 As shown. This electrode consists of a positive electrode main grid 1, a negative electrode main grid 3, an Ag sub-grid 2, and an Ag sub-grid 4. The Ag sub-grid 4 and the negative electrode main grid 3 are perpendicularly intersecting and conducting, while the Ag sub-grid 2 and the positive electrode main grid 1 are perpendicularly intersecting and conducting. Ag sub-grids 2 and 4 correspond to the P / N region of the battery. Currently, the P / N region is designed to maintain a width range of 2mm-3mm, such as... Figure 2 As shown. This width requires very high precision in screen printing, as it can easily cause printing misalignment, leading to poor positive and negative conductivity and affecting battery efficiency and component power. Utility Model Content

[0003] The purpose of this invention is to design an electrode structure for a BC battery in order to solve the above-mentioned problems.

[0004] The present invention achieves the above objectives through the following technical solutions:

[0005] An electrode structure for a BC battery includes n positive electrode main grids and n-1 negative electrode main grids. One negative electrode main grid is located between two positive electrode main grids. Each positive electrode main grid has m sets of positive electrode sub-grids, and each negative electrode main grid has m sets of negative electrode sub-grids. Two adjacent sets of positive electrode sub-grids are located on opposite sides of a positive electrode main grid, and two adjacent sets of negative electrode sub-grids are located on opposite sides of a negative electrode main grid. A set of negative electrode sub-grids is located between two adjacent positive electrode sub-grids on the same side. n and m are both positive integers not less than 2.

[0006] The beneficial effects of this invention are as follows: the positive and negative electrodes and the negative gate corresponding to the P / N regions adopt a multiple parallel design with spacing. Each P / N region is 15-24mm long and 10-18mm wide, with adjacent P / N regions spaced 2-4mm apart. The number of P / N regions on the back side is 20-60, maintaining the electrode printing area of ​​a single PN region, which can effectively solve the problem of printing misalignment. Attached Figure Description

[0007] Figure 1 This is a diagram of the positive and negative electrode structure on the back side of the existing BC technology;

[0008] Figure 2This is a schematic diagram of the PN region corresponding to the back sub-gate of existing BC technology;

[0009] Figure 3 This is a schematic diagram of the PN region on the back of the electrode structure of a BC battery according to the present invention;

[0010] Figure 4 This is a diagram of the positive and negative electrode structure on the back side of a BC battery according to the present invention.

[0011] Figure 5 This is an enlarged view of the positive and negative electrodes on the back side of the electrode structure of a BC battery according to the present invention;

[0012] Figure 6 This is a flowchart of a method for preparing an electrode structure for a BC battery according to the present invention;

[0013] The corresponding figure labels are:

[0014] 1-Positive sub-gate, 2-Positive main gate, 3-Negative main gate, 4-Negative sub-gate. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0017] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0018] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to 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 invention.

[0019] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0020] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" 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 a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] like Figure 3 , Figure 4 , Figure 5 As shown, an electrode structure for a BC battery includes n positive electrode main grids and n-1 negative electrode main grids. One negative electrode main grid is located between two positive electrode main grids. Each positive electrode main grid has m sets of positive sub-grids, and each negative electrode main grid has m sets of negative sub-grids. Two adjacent sets of positive sub-grids are located on opposite sides of a positive electrode main grid, and two adjacent sets of negative sub-grids are located on opposite sides of a negative electrode main grid. A set of negative sub-grids is located between two adjacent positive sub-grids on the same side. n and m are both positive integers not less than 2, facilitating laser patterning and reducing the complexity of the manufacturing process.

[0023] A set of positive sub-gates forms a P-region, and a set of negative sub-gates forms an N-region. The length of the P-region or N-region ranges from 15 to 24 mm, and the width ranges from 10 to 18 mm, collecting current.

[0024] The interval between two adjacent P-regions and N-regions is 2-4mm, which facilitates laser film opening and reduces leakage current.

[0025] The number of P and N regions on the back side is between 20 and 60, and they are interspersed to improve efficiency and Uoc.

[0026] Both the positive electrode main gate and the negative electrode main gate are of the through-type shape. The positive electrode main gate and the positive electrode secondary gate are perpendicularly intersecting and conducting, and the negative electrode main gate and the negative electrode secondary gate are perpendicularly intersecting and conducting, thus drawing out current.

[0027] The width of the positive and negative sub-gates ranges from 13 to 16 mm. The number of positive sub-gates in a set of positive sub-gates ranges from 25 to 45, and the number of negative sub-gates in a set of negative sub-gates ranges from 25 to 45, reducing warpage and fragmentation rate.

[0028] The spacing between two adjacent positive electrode sub-gates in the same group and between two adjacent negative electrode sub-gates in the same group is 0.5-1.5mm.

[0029] like Figure 6 As shown, a method for preparing an electrode structure for a BC battery, used to prepare an electrode structure for a BC battery as described above, includes:

[0030] 1) The original N-type silicon wafers undergo an alkaline polishing process, followed by double-sided polishing.

[0031] 2) After polishing, the silicon wafer undergoes a laser process to etch laser grooves along the gate lines of the P / N region on the back side. The laser pattern is as follows: Figure 4 ;

[0032] 3) A tunneling layer and a polycrystalline silicon layer are formed on the back side by LPCVD, with a film thickness ranging from 70 to 150 nm;

[0033] 4) Boron diffusion is carried out in a high-temperature diffusion furnace to form a P-type semiconductor on the front side, forming a PN junction with a sheet resistance ranging from 320 to 450 ohms, and a P+poly polysilicon doped layer is formed on the back side.

[0034] 5) Partially remove the outermost layer of silicon oxide on the back side to create a patterned structure;

[0035] 6) Use a tank cleaning machine to clean the polycrystalline silicon layer on the back after the film has been opened;

[0036] 7) A tunneling layer and an N+poly polysilicon layer are formed on the back side of the opened film area by LPCVD, with a film thickness ranging from 60 to 150 nm.

[0037] 8) Partially remove the silicon oxide layer on the outermost layer of the N+poly polysilicon layer on the back side to create a film;

[0038] 9) The front PSG layer and the back silicon oxide layer are cleaned by a chain cleaning machine, and then the back polysilicon layer is cleaned by a tank texturing cleaning machine, and the front is texturized.

[0039] 10) Alumina of 3-8 nm is deposited on both sides using an ALD device;

[0040] 11) Silicon nitride antireflection coatings were deposited on the front side by PECVD, with the thickness of the deposited film ranging from 60 to 100 nm.

[0041] 12) Silicon nitride antireflection coatings were deposited on the back side by PECVD, with the thickness of the deposited film ranging from 60 to 100 nm.

[0042] 13) Screen print silver paste on the P / N area of ​​the back side to print patterned electrodes, forming metal grid lines on the back side to transmit current;

[0043] 14) Ohmic contacts are formed through sintering equipment and light injection technology;

[0044] 15) Test the efficiency of the solar cells.

[0045] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. An electrode structure for a BC battery, characterized in that, There are n positive electrode main grids and n-1 negative electrode main grids. One negative electrode main grid is located between two positive electrode main grids. Each positive electrode main grid has m sets of positive electrode sub-grids and each negative electrode main grid has m sets of negative electrode sub-grids. Two adjacent sets of positive electrode sub-grids are located on both sides of a positive electrode main grid, and two adjacent sets of negative electrode sub-grids are located on both sides of a negative electrode main grid. A set of negative electrode sub-grids is located between two adjacent positive electrode sub-grids on the same side. n and m are both positive integers not less than 2.

2. The electrode structure of a BC battery according to claim 1, characterized in that, A set of positive electrode sub-gates constitutes a P-region, and a set of negative electrode sub-gates constitutes an N-region. The length of the P-region or N-region ranges from 15 to 24 mm, and the width ranges from 10 to 18 mm.

3. The electrode structure of a BC battery according to claim 2, characterized in that, The interval between two adjacent P-regions and N-regions is 2-4 mm.

4. The electrode structure of a BC battery according to claim 2, characterized in that, The number of P and N regions on the back is between 20 and 60.

5. The electrode structure of a BC battery according to claim 1, characterized in that, Both the positive electrode main gate and the negative electrode main gate are of the through type. The positive electrode main gate and the positive electrode sub-gate are perpendicularly intersecting and conducting, and the negative electrode main gate and the negative electrode sub-gate are perpendicularly intersecting and conducting.

6. The electrode structure of a BC battery according to claim 1, characterized in that, The width of the positive and negative sub-gates ranges from 13 to 16 mm. The number of positive sub-gates in a set of positive sub-gates ranges from 25 to 45, and the number of negative sub-gates in a set of negative sub-gates ranges from 25 to 45.

7. The electrode structure of a BC battery according to claim 6, characterized in that, The spacing between two adjacent positive electrode sub-gates in the same group and between two adjacent negative electrode sub-gates in the same group is 0.5-1.5mm.

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