阅读说明：本技术 一种光伏电池局部遂穿氧化层钝化接触结构及光伏组件 (Photovoltaic cell local tunneling oxide layer passivation contact structure and photovoltaic module ) 是由 杨洁 孙海杰 王钊 徐孟雷 郑霈霆 张昕宇 金浩 于 2019-11-20 设计创作，主要内容包括：本发明公开了一种光伏电池局部遂穿氧化层钝化接触结构及光伏组件,光伏电池局部遂穿氧化层钝化接触结构包括电池片主体、设置在所述电池片主体表面的第一遂穿氧化层、设置在所述遂穿氧化层表面的所述第一多晶硅薄膜层,所述电池片主体表面包括钝化接触区和吸光区,所述第一遂穿氧化层设置在所述钝化接触区,所述第一多晶硅薄膜层在所述电池片主体表面的投影在所述钝化接触区内。通过第一遂穿氧化层、第一多晶硅薄膜层仅仅覆盖钝化接触区,提高了该区域的钝化水平,降低了电池表面的复合,而第一遂穿氧化层、第一多晶硅薄膜层不在吸光区即非金属接触区,减少了对阳光的遮挡,提高了光吸收效率。(The invention discloses a photovoltaic cell local tunneling oxide layer passivation contact structure and a photovoltaic module. The first tunneling oxide layer and the first polycrystalline silicon thin film layer only cover the passivation contact area, so that the passivation level of the area is improved, and the recombination of the surface of the battery is reduced.)

1. The passivation contact structure is characterized by comprising a cell body, a first tunneling oxide layer arranged on the surface of the cell body, and a first polycrystalline silicon thin film layer arranged on the surface of the tunneling oxide layer, wherein the surface of the cell body comprises a passivation contact area and a light absorption area, the first tunneling oxide layer is arranged in the passivation contact area, and the projection of the first polycrystalline silicon thin film layer on the surface of the cell body is in the passivation contact area.

2. The passivation contact structure of a photovoltaic cell local tunneling oxide layer according to claim 1, further comprising a second tunneling oxide layer and a second polysilicon thin film layer disposed between the first tunneling oxide layer and the cell body, wherein a projection of the second tunneling oxide layer and the second polysilicon thin film layer on the cell body covers the passivation contact region and the light absorption region at the same time.

3. The passivation contact structure of a local tunneling oxide layer of a photovoltaic cell according to claim 2, wherein the first and second tunneling oxide layers have a thickness of 5nm to 50 nm.

4. The photovoltaic cell localized tunneling oxide layer passivation contact structure of claim 3, wherein the thickness of the first polysilicon thin film layer is 20nm to 300 nm.

5. The photovoltaic cell localized tunneling oxide layer passivation contact structure of claim 3, wherein the thickness of the second polysilicon thin film layer is 5nm to 50 nm.

6. The photovoltaic cell local tunneling oxide passivation contact structure of claim 5, wherein a thickness of the first tunneling oxide layer is equal to a thickness of the second tunneling oxide layer.

7. The photovoltaic cell localized tunnel oxide layer passivation contact structure of claim 6, wherein the cell body is a single-sided cell body or a double-sided cell body.

8. A photovoltaic module comprising a cell body and a tunnel oxide passivation contact structure according to any of claims 1-7 disposed on the cell body.

Technical Field

The invention relates to the technical field of photovoltaic cells, in particular to a photovoltaic cell local tunneling oxide layer passivation contact structure and a photovoltaic module.

Background

With the development of the solar photovoltaic market, people have an increasingly urgent need for efficient crystalline silicon cells. Due to the continuous development of photovoltaic technology, the manufacturing technology cost of the photovoltaic cell is continuously reduced, the market competition is more intense, and the high-quality low-cost photovoltaic cell is a main factor for improving the competitiveness.

For crystalline silicon solar energy, the surface passivation technology is mature day by day, and the passivation level tends to be saturated. The main factor for limiting the open-circuit voltage and further improving the conversion efficiency of the crystalline silicon solar cell is that the composite current of the metal electrode and the crystalline silicon surface contact area is too large and 2 orders of magnitude higher than that of the non-metal contact area.

The tunneling oxide layer passivation contact technology can compound the metal contact area, however, the strong absorption of the silicon-based film in the structure to sunlight limits the use of the tunneling oxide layer passivation contact technology on the front surface of the crystalline silicon solar cell, which results in that the further improvement of the conversion efficiency of the crystalline silicon solar cell is hindered.

Disclosure of Invention

The invention aims to provide a photovoltaic cell local tunneling oxide layer passivation contact structure and a photovoltaic module, which are compatible with the existing mass production process of mass-produced crystalline silicon cells, can be quickly put into mass production, and play a role in quickly improving efficiency and reducing cost.

In order to solve the foregoing technical problem, an embodiment of the present invention provides a photovoltaic cell local tunneling oxide layer passivation contact structure, including a cell body, a first tunneling oxide layer disposed on a surface of the cell body, and a first polysilicon thin film layer disposed on a surface of the tunneling oxide layer, where the surface of the cell body includes a passivation contact area and a light absorption area, the first tunneling oxide layer is disposed on the passivation contact area, and a projection of the first polysilicon thin film layer on the surface of the cell body is in the passivation contact area.

The light-absorbing layer is arranged between the first tunneling oxide layer and the cell main body, and the projections of the second tunneling oxide layer and the second polycrystalline silicon thin film layer on the cell main body cover the passivation contact area and the light-absorbing area.

Wherein the thickness of the first tunneling oxide layer and the second tunneling oxide layer is 0.5nm to 5 nm.

Wherein the thickness of the first polysilicon thin film layer is 20nm-300 nm.

Wherein the thickness of the second polysilicon thin film layer is 5nm-50 nm.

Wherein the thickness of the first tunneling oxide layer is similar to the thickness of the second tunneling oxide layer.

The battery piece main body is a single-sided battery piece main body or a double-sided battery piece main body.

In addition, the embodiment of the invention also provides a photovoltaic module, which comprises a cell main body and the photovoltaic cell local tunneling oxide layer passivation contact structure arranged on the cell main body.

Compared with the prior art, the photovoltaic cell local tunneling oxide layer passivation contact structure and the photovoltaic module provided by the embodiment of the invention have the following advantages:

according to the photovoltaic cell local tunneling oxide layer passivation contact structure and the photovoltaic module provided by the embodiment of the invention, the passivation contact area is only covered by the first tunneling oxide layer and the first polycrystalline silicon thin film layer, so that the passivation level of the area is improved, the compounding of the cell surface is reduced, the first tunneling oxide layer and the first polycrystalline silicon thin film layer are not in the light absorption area, namely the non-metal contact area, the shielding of sunlight is reduced, the light absorption efficiency is improved, and the photovoltaic cell local tunneling oxide layer passivation contact structure and the photovoltaic module are compatible with the existing mass production crystalline silicon cell mass production process, can be rapidly put into mass production, and play a role in rapidly increasing efficiency and reducing cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a local tunneling oxide passivation contact structure of a photovoltaic cell according to an embodiment of the present invention;

fig. 2 is a schematic structural view of another embodiment of a passivation contact structure for a local tunnel oxide layer of a photovoltaic cell according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to fig. 2, fig. 1 is a schematic structural diagram of a local tunneling oxide passivation contact structure of a photovoltaic cell according to an embodiment of the present invention; fig. 2 is a schematic structural view of another embodiment of a passivation contact structure for a local tunnel oxide layer of a photovoltaic cell according to the present invention.

In one specific embodiment, the photovoltaic cell local tunneling oxide layer passivation contact structure includes a cell body 10, a first tunneling oxide layer 20 disposed on a surface of the cell body 10, and a first polysilicon thin film layer 30 disposed on a surface of the tunneling oxide layer, where the surface of the cell body 10 includes a passivation contact area and a light absorption area, the first tunneling oxide layer 20 is disposed on the passivation contact area, and a projection of the first polysilicon thin film layer 30 on the surface of the cell body 10 is in the passivation contact area.

Only cover the passivation contact region through first tunnel oxide layer 20, first polycrystalline silicon thin film layer 30, improved the passivation level in this region, reduced the compound on battery surface, and first tunnel oxide layer 20, first polycrystalline silicon thin film layer 30 are not in the non-metal contact region that absorbs light district promptly, have reduced sheltering from to sunshine, have improved light absorption efficiency, and compatible with current volume production crystalline silicon battery volume production technology, can put into volume production fast, play to promote fast and fall the effect of this.

Since the existing passivation contact areas are covered on the front side, but only on the metal contact areas, in the present invention, an increase in cell efficiency is achieved in this way.

Since the metal electrode is finally sintered on the surface of the first tunnel oxide layer 20, the thicknesses of the first tunnel oxide layer 20 and the first polysilicon thin film layer 30 are very small, in the process of arranging the metal electrode, the first crystal silicon thin film layer is easy to burn through to reach the cell main body 10 to cause damage, in order to avoid the situation, the recombination of the metal contact area is further reduced, the performance of the battery is improved, in an embodiment of the invention, the local tunnel oxide passivation contact structure of the photovoltaic cell further includes a second tunnel oxide layer 40 and a second polysilicon thin film layer 50 disposed between the first tunnel oxide layer 20 and the cell body 10, the projections of the second tunneling oxide layer 40 and the second polysilicon thin film layer 50 on the cell body 10 cover the passivation contact region and the light absorption region at the same time.

In the structure, the doping concentration of the first polycrystalline silicon thin film layer 30 is greater than that of the second polycrystalline silicon thin film layer 50, a high-low junction structure is formed, and the problem of incompatibility between complete passivation and light absorption of the passivation contact structure and penetration damage of a metal electrode is solved by utilizing a passivation contact high-low junction structure, so that the conversion efficiency of the battery is improved.

In the present invention, the thickness and the forming method of the tunnel oxide layer are not limited, and the thickness of the first tunnel oxide layer 20 and the second tunnel oxide layer 40 is generally 0.5nm to 5 nm.

The thickness and deposition method of the crystalline silicon thin film layer are not limited in the present invention, and the thickness of the first polysilicon thin film layer 30 and the second polysilicon thin film layer 50 is generally 20nm to 300 nm.

Preferably, the thickness of the first tunnel oxide layer 20 is equal to the thickness of the second tunnel oxide layer 40.

Preferably, the thickness of the first polysilicon thin film layer 30 is equal to the thickness of the second polysilicon thin film layer 50.

The battery sheet main body 10 in the present invention may be a single-sided battery sheet main body 10, or may be a double-sided battery sheet main body 10.

In one embodiment, the process for the photovoltaic cell local tunneling oxide layer passivation contact structure is as follows:

(1) and forming a first tunneling oxide layer 20 on the surface of the silicon wafer. The silicon wafer may be a single crystal or polycrystalline silicon wafer, the doping type on the surface of the silicon wafer may be P-type or N-type, the surface of the silicon wafer may be a silicon wafer after being damaged, polished or textured, and the first tunnel oxide layer 20 may be deposited by thermal oxidation, thermal HNO3 oxidation or a CVD method, and has a thickness of 0.5-5 nm.

(2) A first polysilicon film is formed on the first tunnel oxide layer 20. Specifically, the polysilicon film may be a doped or intrinsic polysilicon film, the preparation method may be one of CVD deposition, PVD deposition and chemical spin coating, and may or may not include a subsequent annealing process, and the thickness of the first polysilicon film is between 20nm and 300 nm.

(3) And depositing a local corrosion-resistant protective layer on the surface of the first polycrystalline silicon film to protect a passivation contact area of the tunneling oxide layer to be reserved. Specifically, the pattern may be organic or inorganic, and the partial patterning may be performed by inkjet printing or screen printing.

(4) And etching the polysilicon film in the non-protection area by using the first chemical liquid. Specifically, the first chemical liquid may be an alkali or an alkali mixture liquid, and the liquid may etch the first polysilicon thin film layer 30, but does not corrode the first tunneling oxide layer 20, and may control the etching to stay on the surface of the first tunneling oxide layer 20, so as to protect the surface topography of the cell main body 10;

(5) and removing the corrosion-resistant protective layer by using second chemical liquid. Specifically, the corrosion-resistant protective layer can be removed by acid or alkali mixed liquid, and the corrosion-resistant protective layer can be removed without damaging the surface of the cell main body 10 by the liquid etching environment;

(6) and removing the first tunnel oxide layer 20 in the etched area by using a third chemical liquid. Specifically, the third chemical liquid is an HF solution, and the etching rate can be controlled by controlling the reaction time and the solution concentration.

In another embodiment, the process for the photovoltaic cell local tunneling oxide layer passivation contact structure is as follows:

(1) and forming a second tunneling oxide layer 40 on the surface of the silicon wafer. The silicon wafer can be a monocrystalline or polycrystalline silicon wafer, the doping type on the surface of the silicon wafer can be a P type or an N type, and the surface of the silicon wafer can be subjected to damage removal, polishing or texturing. Second tunnel oxide layer 40 may be deposited using thermal oxidation, thermal HNO3 oxidation, or CVD methods to a thickness of between 0.5nm and 5 nm.

(2) And a second polysilicon film is formed on the second tunnel oxide layer 40. The second polysilicon film can be doped or intrinsic polysilicon film, the preparation method comprises CVD deposition, PVD deposition, chemical spin coating and the like, and can or can not comprise a subsequent annealing process, and the thickness of the second polysilicon film is between 5nm and 50 nm.

(3) And forming a first tunneling oxide layer 20 on the surface of the second polysilicon film. In the specific implementation case, the silicon wafer can be a monocrystalline or polycrystalline silicon wafer, the doping type on the surface of the silicon wafer can be a P type or an N type, and the surface of the silicon wafer can be after damage removal, polishing or texturing. The tunnel oxide layer may be deposited by thermal oxidation, thermal HNO3 oxidation, or CVD methods to a thickness of 0.5-5 nm.

(4) A first polysilicon film is formed on the first tunnel oxide layer 20. In a specific implementation case, the polysilicon thin film may be a doped or intrinsic polysilicon thin film, the preparation method includes CVD deposition, PVD deposition, chemical spin coating, and the like, and may or may not include a subsequent annealing process, and the thickness of the first silicon thin film is between 20nm and 300 nm.

(5) And forming a local corrosion-resistant protective layer on the surface of the first polycrystalline silicon film to protect the passivation contact area of the tunneling oxide layer to be reserved. Can be organic or inorganic, and the local patterning can be realized by adopting an ink-jet printing or screen printing mode.

(6) And etching the first polysilicon film layer 30 in the non-protective area by using a first chemical liquid. The first etching chemical liquid is alkali or an alkali mixed liquid, and the liquid can etch the first polysilicon thin film layer 30 without corroding the first tunneling oxide layer 20, and the etching is controlled to stay on the surface of the first tunneling oxide layer 20 to protect the first tunneling oxide layer 20;

(7) and removing the corrosion-resistant protective layer by using second chemical liquid. The second chemical liquid can be mixed liquid of acid or alkali, and the liquid etches the environment and can remove the corrosion-resistant protective layer without damaging the second polycrystalline silicon thin film layer 50 and the first polycrystalline silicon thin film layer 30;

(8) and removing the first tunneling oxide layer in the etched area by using a third chemical liquid, wherein the third chemical liquid is generally an HF solution.

By adopting the process, the process method for passivating the contact structure by the local tunneling oxide layer does not need a PECVD (plasma enhanced chemical vapor deposition) mask process, and the process is simple; the process method for passivating the contact structure by the local tunneling oxide layer does not use a laser etching process, so that the damage of a silicon wafer substrate caused by laser is avoided; the local tunneling oxide layer passivation contact structure process method can control the etching of polycrystalline silicon on the surface of the tunneling oxide layer, can protect the surface appearance of the silicon substrate and avoid a secondary texturing process; the passivation contact upgrading structure of the local tunneling oxide layer solves the problem of incompatibility between complete passivation and light absorption of the passivation contact structure and penetration damage of a metal electrode by utilizing a passivation contact high-low junction structure, and improves the conversion efficiency of the battery; the local tunneling oxide layer passivation contact upgrading structure process method does not need a PECVD mask process, and is simple in process; the local tunneling oxide layer passivation contact structure process method does not use a laser etching process, so that the damage of laser to the ultrathin passivation contact structure and the silicon substrate is avoided; the local tunneling oxide layer passivation contact structure process method can control the etching of polycrystalline silicon on the surface of the tunneling oxide layer and can keep an ultrathin passivation contact structure in a nonmetal contact area.

In addition, the embodiment of the invention also provides a photovoltaic module, which comprises a cell main body and the photovoltaic cell local tunneling oxide layer passivation contact structure arranged on the cell main body.

Since the photovoltaic module includes the above-described passivation contact structure for the local tunneling oxide layer of the photovoltaic cell, the same beneficial effects are obtained, and the details are not repeated herein.

In summary, according to the photovoltaic cell local tunneling oxide layer passivation contact structure and the photovoltaic module provided by the embodiments of the present invention, the first tunneling oxide layer and the first polysilicon thin film layer only cover the passivation contact region, so that the passivation level of the region is improved, and the recombination on the cell surface is reduced, and the first tunneling oxide layer and the first polysilicon thin film layer are not in the light absorption region, i.e., the non-metal contact region, so that the shielding of sunlight is reduced, the light absorption efficiency is improved, and the structure and the module are compatible with the existing mass production process of crystalline silicon cells, and can be quickly put into mass production, thereby playing a role in quickly improving the efficiency and reducing the cost.

The photovoltaic cell local tunneling oxide layer passivation contact structure and the photovoltaic module provided by the invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.