Novel N-type double-sided solar cell

Abstract

The utility model discloses a novel N-type double-sided solar cell, which relates to the technical field of solar cells, and comprises an N-type silicon wafer substrate, a pn emitter junction layer, a passivation anti-reflection layer, a front electrode and a suede layer are arranged on the N-type silicon wafer substrate, the suede layer comprises a first pyramid suede and a second pyramid suede, pits are arranged on the second pyramid suede, and the second pyramid suede is provided with a second pyramid suede. Edge areas are arranged on two sides of the substrate; a second pyramid suede with a smaller average size and irregular pits are arranged below the front electrode, and a first tower base region with a smaller size is arranged below the back electrode, so that contact points between the front electrode and the conducting layer and between the back electrode and the conducting layer are increased, reduction of contact resistance is facilitated, the passivation effect of the passivation anti-reflection layer is improved, and the service life of the passivation anti-reflection layer is prolonged. By arranging the edge region, the isolation distance between the front pn emitter junction layer and the back tower base layer is increased, and the leakage current of the N-type double-sided battery is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to solar cell technical field, concretely relates to a novel N type bifacial solar cell. BACKGROUND

[0002] In recent years, the vigorous development of renewable energy is increasing, among which solar energy is the most common. Compared with traditional energy, solar energy has the characteristics of simple use, safety and no pollution, and becomes the focus of research in the field of renewable new energy. The basic principle of solar cell power generation is photovoltaic effect, and solar cell is a new energy device for converting solar light into electric energy. The bifacial solar cell in the solar cell utilizes the front and back light receiving surfaces to obtain higher photocurrent density and greatly improve the power generation power. Bifacial solar cells are mainly divided into N type and P type. At present, N type bifacial solar cells have replaced P type bifacial solar cells and become the mainstream product in the solar cell industry.

[0003] For example, the utility model patent with publication number CN206271712U and the name of "a bifacial crystalline silicon solar cell" is provided with a textured structure on the front single crystal silicon substrate, and the back surface adopts a polished uniform surface.

[0004] In order to optimize the electrical performance of the N type bifacial solar cell, the contact resistance between the electrode and the conductive layer in the electrode area needs to be as low as possible, and the passivation effect in the non-electrode area needs to be as high as possible. The former requires that the average size of the textured structure / tower base platform in the electrode area be reduced to provide more metal electrode contact points, and the latter requires that the average size of the textured structure / tower base platform be increased. However, some existing solar bifacial cells, such as the above-mentioned patent, have the same average size of the textured structure / tower base platform in the electrode area and the non-electrode area, which cannot simultaneously optimize the contact resistance between the electrode / conductive layer and the passivation effect in the non-electrode area, so that the electrical performance of the bifacial cell is limited. UTILITY MODEL CONTENTS

[0005] The utility model aims to provide a novel N type bifacial solar cell to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above-mentioned purpose, the utility model provides the following technical scheme: a novel N type bifacial solar cell, comprising an N type silicon wafer substrate, the front surface of the N type silicon wafer substrate is sequentially formed with a pn emission junction layer, a passivation anti-reflection layer and a front electrode from inside to outside, further comprising a textured layer formed on the front surface of the N type silicon wafer substrate, the textured layer comprises a first pyramid textured surface and a second pyramid textured surface, the second pyramid textured surface is arranged at the bottom of the front electrode, the second pyramid textured surface is provided with irregular pits with a size of 10-400nm, and the two sides of the substrate are provided with edge areas, and the width of the edge area is 0.05-0.5mm.

[0007] Preferably, the N-type silicon wafer substrate is provided with a tower base layer on the back surface, and the back electrode is arranged on the tower base layer.

[0008] Preferably, the tower base layer is divided into a first tower base area and a second tower base area, and the first tower base area is located on the side close to the N-type silicon wafer substrate.

[0009] Preferably, the passivation anti-reflection layer is composed of an upper silicon nitride film and a lower aluminum oxide film.

[0010] In the above technical solution, the present application provides a novel N-type bifacial solar cell, which has the following beneficial effects: the pyramid texturing layer is divided into different sizes, the second pyramid texturing layer with a smaller average size is arranged under the front electrode, the irregular pits with a size of 10-500 nm are arranged on the pyramid texturing layer in this area, the first tower base area with a smaller average size is arranged under the back electrode, thereby increasing the contact points between the front electrode, the back electrode and the conductive layer, reducing the contact resistance, improving the passivation effect of the passivation anti-reflection layer, and improving the electrical performance of the N-type bifacial solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0012] Figure 1 The overall structure schematic diagram of the embodiments of the present application is provided.

[0013] MARKED EXPLANATION:

[0014] 1, N-type silicon wafer substrate; 2, first pyramid texturing layer; 201, second pyramid texturing layer; 3, pn emitter junction layer; 4, edge area; 5, passivation anti-reflection layer; 6, front electrode; 7, first tower base area; 8, second tower base area; 9, back electrode. DETAILED DESCRIPTION

[0015] In order to make those skilled in the art better understand the technical solutions of the present application, the present application will be further described in detail with reference to the drawings.

[0016] Please refer to Figure 1The utility model provides a novel N type bifacial solar cell, the technical scheme that the utility model provides is including N type silicon wafer substrate 1, N type silicon wafer substrate 1 front face from inside to outside forms successively has pn emission junction layer 3, passivation antireflection layer 5 and front electrode 6, still include the rough layer formed in N type silicon wafer substrate 1 front face, rough layer includes first pyramid rough 2 and second pyramid rough 201, and second pyramid rough 201 sets up at the bottom of front electrode 6, and the irregular recess of size in 10-400nm is arranged on second pyramid rough 201, and the both sides of substrate are provided with edge area 4, and the width of edge area 4 is 0.05-0.5mm, the average surface area of second pyramid rough 201 is less than the average surface area of first pyramid rough 2, and pn emission junction layer 3 is above rough layer, and pn emission junction layer 3 is high concentration's boron doped pn emission junction, and the pn emission junction of front face is as front P type conducting layer, and second pyramid rough 201 is directly below front electrode 6, and the average surface area of second pyramid rough 201 is less than the average surface area of first pyramid rough 2, so that the surface area of both has difference, improves the quantity of second pyramid rough 201 under unit area, thereby improves the surface area of second pyramid rough 201 whole, and through the irregular recess of size in 10-500nm arranged in second pyramid rough 201, the contact area of second pyramid rough 201 and front electrode 6 is increased, thereby the contact resistance of second pyramid rough 201 is reduced, can reduce the limitation to the surface area of first pyramid rough 2 simultaneously, effectively improves the passivation effect of passivation antireflection layer 5 on first pyramid rough 2, improves the electric performance of N type bifacial cell, and edge area 4 has no pn emission junction, so that the isolation distance of front pn emission junction layer 3 and back pn emission junction layer 3 increases, helps to reduce the leakage current of N type bifacial cell.

[0017] Specifically, the tower base layer is formed on the back surface of the N-type silicon wafer substrate 1, and the back electrode 9 is arranged on the tower base layer; the passivation antireflection layer 5 is wrapped around the N-type silicon wafer substrate 1 except for the front electrode 6 and the back electrode 9; the tower base layer and the pn emission junction layer 3 are both high-concentration phosphorus-doped pn emission junctions, and the tower base layer serves as a front N-type conductive layer; the tower base layer can be a polycrystalline material covering the surface of the N-type silicon wafer substrate 1, separated from the substrate by a 0.5-2.5 nm thick ultra-thin dielectric film, or embedded in the back of the substrate and has the same crystal structure as the N-type silicon wafer substrate 1.

[0018] Specifically, the tower base layer is divided into a first tower base area 7 and a second tower base area 8, the first tower base area 7 is located at the side of the back electrode 9 close to the N-type silicon wafer substrate 1, the passivation anti-reflection layer 5 is wrapped in the N-type silicon wafer substrate 1 except the positive electrode 6 and the back electrode 9, the width of the first tower base area 7 is greater than the back electrode 9 by 10-250um, the back of the N-type silicon wafer substrate 1 is the second tower base area 8 except the edge area 4 and the first tower base area 7, the tower base area shape is composed of multiple trapezoidal shapes, the average size of the tower base platform structure of the first tower base area 7 is smaller than the average size of the tower base platform structure of the second tower base area 8, the average size of the tower base platform structure of the second tower base area 8 is less than or equal to the edge area 4, due to the size of the tower base platform structure distinguishing the first tower base area 7 and the second tower base area 8, the tower base platform size of the first tower base area 7 is smaller, and the tower base platform size of the second tower base area 8 is larger, which helps to reduce the contact resistance between the back electrode 9 and the tower base layer, and improve the passivation effect of the second tower base area 8, and the impurity concentration of the first tower base area 7 is higher than that of the second tower base area 8, which helps to reduce the contact resistance between the back electrode 9 and the conductive layer, and improve the passivation effect of the non-electrode area.

[0019] Specifically, the passivation anti-reflection layer 5 is composed of an upper silicon nitride film and a lower aluminum oxide film, the silicon nitride film is located at the surface, and the aluminum oxide film is located at the inner side, so that the advantages of each thin film can be fully utilized, the high passivation performance of the aluminum oxide film can be utilized, the good anti-reflection effect and mechanical performance of the silicon nitride film can be utilized, better passivation and anti-reflection effects can be achieved, and corresponding high-concentration impurities can be introduced into the pn emission junction layer 3 and the tower base layer through ion implantation or diffusion process, so as to increase the carrier concentration and reduce the contact resistance.

[0020] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and modifications can be made to the embodiments without departing from the principles and spirits of the present application, the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A novel N-type bifacial solar cell, comprising an N-type silicon substrate (1), wherein a pn emitter junction layer (3), a passivation antireflection layer (5), and a front electrode (6) are sequentially formed from the inside to the outside on the front side of the N-type silicon substrate (1), characterized in that, It also includes a textured layer formed on the front side of the N-type silicon wafer substrate (1), the textured layer including a first pyramid textured surface (2) and a second pyramid textured surface (201), the second pyramid textured surface (201) is disposed at the bottom of the front electrode (6), the second pyramid textured surface (201) is provided with irregular pits with a size of 10-400nm, and edge regions (4) are provided on both sides of the substrate, the width of the edge regions (4) is 0.05-0.5mm.

2. A novel N-type bifacial solar cell according to claim 1, characterized in that, A tower base layer is formed on the back side of the N-type silicon substrate (1), and a back electrode (9) is disposed on the tower base layer.

3. A novel N-type bifacial solar cell according to claim 2, characterized in that, The base layer is divided into a first base area (7) and a second base area (8). The first base area (7) is located on the side of the back electrode (9) close to the N-type silicon substrate (1).

4. A novel N-type bifacial solar cell according to claim 3, characterized in that, The passivation antireflection layer (5) is composed of an upper silicon nitride film and a lower aluminum oxide film.

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