CN108346707A - A kind of hetero-junctions crystal silicon double-side solar cell structure that entering light region is blocked without heavily doped layer - Google Patents

Abstract

A kind of hetero-junctions crystal silicon double-side solar cell structure that entering light region is blocked without heavily doped layer, using N-shaped crystal silicon chip as substrate, transmitting pole-face is divided into emitter conductive region and passivation entering light region：Emitter conductive region is made of intrinsic amorphous silicon passivation layer, heavily-doped p-type amorphous silicon layer, metal grid lines I successively outward substrate, and passivation entering light region is penetrated a layer I by passivated reflection reducing and constituted；Back of the body electric field surface is divided into passivation entering light region and back of the body electric field conductive region：Entering light region is followed successively by highly doped n-type crystal silicon layer II by substrate outward, passivated reflection reducing penetrates a layer II for passivation；Back of the body electric field conductive region is followed successively by highly doped n-type crystal silicon layer II, metal grid lines II by substrate outward.The present invention obtains the characteristic of high open circuit voltage and high short circuit current under the premise of keeping the characteristic of the two-sided entering light of crystal-silicon solar cell, improves the generating capacity of crystal-silicon solar cell to the greatest extent.

Description

A heterogeneous crystal silicon double-sided solar cell with no heavily doped layer blocking the light-incoming region structure

technical field

The invention belongs to the fields of solar cells and semiconductor devices. It involves the preparation technology of solar cells.

Background technique

For crystalline silicon heterojunction solar cells, its general structure is on an n-type textured crystalline silicon substrate, one side is an intrinsic amorphous silicon passivation layer, a p-type amorphous silicon emitter layer, TCO transparent conductive film, silver grid line, the other side is the structure of intrinsic amorphous silicon passivation layer, n-type amorphous silicon emitter layer, TCO transparent conductive film, and silver grid line. The solar cell with this structure has the advantage of high open circuit voltage, but the disadvantage is that the TCO layer and the intrinsic and doped amorphous silicon layer cause a large light absorption loss, especially the amorphous silicon layer, which leads to the short-circuit current of this type of solar cell. high. How to improve the short-circuit current of this type of solar cell through the improvement of device structure design and preparation technology is an important direction for its performance improvement. In addition, one of the main elements of the TCO material used in solar cells with this structure is indium, which has very little reserves on the earth and is very expensive, which is one of the main factors leading to the high cost of the solar cell, so reducing the amount of TCO is also an important factor. An important direction for the improvement of solar cells with this structure.

Contents of the invention

The object of the present invention is to propose a heterogeneous crystal silicon double-sided solar cell structure without heavy doping layer shielding in the light-incoming region, and further improve the performance of the crystalline silicon double-sided solar cell by increasing the short-circuit current of the crystalline silicon heterojunction solar cell. Power generation efficiency; reduced consumption of valuable raw materials.

The present invention is achieved through the following technical solutions.

According to the present invention, a heterogeneous crystal silicon double-sided solar cell structure with no heavily doped layer shielding the light-incoming region uses an n-type crystal silicon wafer (5) as a substrate, and its emitter surface is divided into an emitter-conductive region And passivation-light-incoming area: the emitter-conductive area is sequentially composed of intrinsic amorphous silicon passivation layer (3), heavily doped p-type amorphous silicon layer (2), metal gate line I (1) from the base to the outside Composition, the passivation-light-incoming area is composed of the passivation anti-reflection layer I (4), and the two areas cross and do not overlap.

In order to improve the contact conductivity between the metal gate line I (1) and the heavily doped p-type amorphous silicon layer (2), it is preferable to insert a transitional TCO layer between the two.

The passivation anti-reflection layer I (4) of the present invention is preferably a silicon dioxide/silicon nitride composite thin film.

A heterogeneous crystal silicon double-sided solar cell structure without heavy doping layer shielding in the light-incoming region according to the present invention is a double-sided light-incoming solar cell, and its positive and negative electrodes are respectively located on the base of an n-type crystalline silicon wafer (5) of the two surfaces. The structure of the other side (back electric field surface) of the solar cell other than the emitter surface is divided into a passivation-light-incoming area and a back electric field-conductive area: the passivation-light-incoming area is heavily doped n-type crystal from the base to the outside Silicon layer II (6), passivation anti-reflection layer II (7); the back electric field-conductive region consists of heavily doped n-type crystalline silicon layer II (6) and metal gate line II (8) from the base to the outside. These two areas are intersected and do not overlap.

Wherein, the passivation anti-reflection layer II (7) is preferably silicon nitride.

Furthermore, in order to improve the performance of the device, the n-type crystalline silicon wafer (5) of the present invention can be textured on both sides, so as to further increase the short-circuit current of the solar cell.

Furthermore, the textures of both sides of the n-type crystalline silicon wafer (5) can be different, one side adopts a textured surface with a smaller size pyramid structure, and the other side adopts a larger size pyramid textured surface or a polished structure without pyramids.

Further, areas with metal grid lines (metal grid line I, metal grid line II) can be polished or made of larger-sized pyramid suede to reduce recombination loss and increase the open-circuit voltage of the solar cell.

Furthermore, the ratio of the total coverage area of the metal grid lines (metal grid lines I and metal grid lines II) on the device surface is preferably 1-3%, so as to improve the short-circuit current of the solar cell and ensure sufficient electrical conductivity.

The technical effect of the invention is: on the premise of maintaining the characteristics of double-sided light input of the crystalline silicon solar cell, the characteristics of high open circuit voltage and high short-circuit current are obtained at the same time, and the power generation capacity of the crystalline silicon solar cell is improved to the greatest extent. The mechanism is to obtain a high open-circuit voltage through the amorphous silicon emitter and supporting structure under the coverage area of the metal grid line; the structure of the surface anti-reflection passivation layer in the place where there is no metal grid line is compared with the conventional amorphous silicon/crystal Silicon heterojunction solar cells can reduce shading loss and effectively convert more incident sunlight into photogenerated carriers. The photogenerated holes generated in the device flow concentratedly to the emitter region, forming a large current effect similar to that of a concentrating solar cell, which can further increase the built-in potential of the solar cell, thereby further increasing the voltage of the solar cell. In addition, the present invention can completely avoid the use of expensive TCO compared to the HIT structure.

Description of drawings

Accompanying drawing 1 is the structure diagram of the present invention. Among them: 1 is the metal gate line I; 2 is the heavily doped p-type amorphous silicon layer; 3 is the intrinsic amorphous silicon layer; 4 is the passivation anti-reflection layer I; 5 is the n-type crystalline silicon wafer; Doped n-type crystalline silicon layer II; 7 is the passivation anti-reflection layer II; 8 is the metal grid line II.

Detailed ways

The invention will be further illustrated by the following examples.

Example 1.

As shown in Figure 1, a heterogeneous crystal silicon double-sided solar cell structure with no heavily doped layer shielding the light entering region. Both sides of the n-type crystalline silicon wafer (5) are textured with an average pyramid structure of ~1 micron, the heavily doped n-type crystalline silicon layer II (6) has a thickness of 100nm, and the passivation anti-reflection layer I (4) and passivation Both the anti-reflection layer II (7) are made of silicon nitride film, the metal grid line I (1) and the metal grid line II (8) both adopt the Ag grid line structure with the main and auxiliary grids, and the covering area is 2% of the surface area of the silicon wafer. %. The structure has excellent double-sided light-incoming characteristics, that is, any side can be used as the main light-incoming surface. If it is used as a single-side light-incoming solar cell, a layer of metal can be plated on the backlight as a reflective layer to increase the short-circuit current of the single-side light-incoming solar cell.

Example 2.

As shown in Figure 1, a heterogeneous crystal silicon double-sided solar cell structure with no heavily doped layer shielding the light entering region. The passivation-light-incoming regions on both sides of the n-type crystalline silicon wafer (5) adopt a pyramid-structure suede surface with an average of ~1 micron, and the areas covered by grid lines adopt a chemically polished structure. The thickness of the heavily doped n-type crystalline silicon layer II (6) is 200nm, the passivation anti-reflection layer I (4) and the passivation anti-reflection layer II (7) are both made of silicon dioxide/silicon nitride composite film, metal grid lines Both I (1) and metal grid line II (8) adopt the Ti/Pd/Ag composite metal grid line structure with main and auxiliary grids, and the covering area is 1% of the surface area of the silicon wafer. The structure has excellent double-sided light-incoming characteristics, that is, any side can be used as the main light-incoming surface. If it is used as a single-side light-incoming solar cell, a layer of metal can be plated on the backlight as a reflective layer to increase the short-circuit current of the single-side light-incoming solar cell.

Claims (8)

1. the hetero-junctions crystal silicon double-side solar cell structure that a kind of entering light region is blocked without heavily doped layer, it is characterized in that with N-shaped Crystal silicon chip（5）As substrate, transmitting pole-face is divided into emitter-conductive region and passivation-entering light region：Emitter-conduction Region is by substrate outward successively by intrinsic amorphous silicon passivation layer（3）, heavily-doped p-type amorphous silicon layer（2）, metal grid lines I（1）Structure At a layer I is penetrated in passivation-entering light region by passivated reflection reducing（4）It constitutes, the two region cross-distributions and is not overlapped；

It is carried on the back electric field surface and is divided into passivation-entering light region and back of the body electric field-conductive region：Passivation-entering light region by substrate outward successively For highly doped n-type crystal silicon layer II（6）, passivated reflection reducing penetrate a layer II（7）；Back of the body electric field-conductive region is attached most importance to successively outward by substrate Adulterate N-shaped crystal silicon layer II（6）, metal grid lines II（8）, the two region cross-distributions and it is not overlapped.

2. the hetero-junctions crystal silicon double-side solar cell that a kind of entering light region according to claim 1 is blocked without heavily doped layer Structure, it is characterized in that in metal grid lines I（1）With heavily-doped p-type amorphous silicon layer（2）Between be inserted into a transition tco layer.

3. the hetero-junctions crystal silicon double-side solar cell that a kind of entering light region according to claim 1 is blocked without heavily doped layer Structure, it is characterized in that the passivated reflection reducing penetrates a layer I（4）For silicon dioxide/silicon nitride laminated film.

4. the hetero-junctions crystal silicon double-side solar cell that a kind of entering light region according to claim 1 is blocked without heavily doped layer Structure, it is characterized in that the passivated reflection reducing penetrates a layer II（7）For silicon nitride.

5. the hetero-junctions crystal silicon double-side solar cell that a kind of entering light region according to claim 1 is blocked without heavily doped layer Structure, it is characterized in that the N-shaped crystal silicon chip（5）For two-sided making herbs into wool.

6. the hetero-junctions crystal silicon double-side solar cell that a kind of entering light region according to claim 1 is blocked without heavily doped layer Structure, it is characterized in that the N-shaped crystal silicon chip（5）Two-sided making herbs into wool situation：Small size pyramid structure is used on one side Matte, in addition one side is using large-sized pyramid matte or without pyramidal polishing structure.

7. the hetero-junctions crystal silicon double-side solar cell that a kind of entering light region according to claim 1 is blocked without heavily doped layer Structure, it is characterized in that there is metal grid lines region to polish or do the pyramidal matte of large scale.

8. the hetero-junctions crystal silicon double-side solar cell that a kind of entering light region according to claim 1 is blocked without heavily doped layer Structure, it is characterized in that the total area coverage ratio of device surface metal grid lines is 1 ~ 3%.