阅读说明：本技术 一种双面p型电池片的背面结构及其制备方法 (Back structure of double-sided P-type battery piece and preparation method thereof ) 是由 单伶宝 于 2020-08-05 设计创作，主要内容包括：本发明公开了一种双面P型电池片的背面结构及其制备方法,包括硅衬底层,硅衬底层上设置钝化层,钝化层上设置铝层,铝层能穿过钝化层与硅衬底层接触,铝层在高温下生成铝硅化合物,在铝硅化合物上设置金属导线层。本结构的发明使得双面P型电池片的低成本的电镀铜取代银浆印刷成为简易可行的工艺,有助于双面P型电池的生产成本大幅降低,同时由于使用电镀铜取代网印银浆,可增加受光面积与提升填充因子(FF)进而提升整体电池发电效率,形成铝硅化合物在进行电池片的双面电镀时使得电池的背面可与阴极形成良好电接触通路,避免阻抗太高而无法形成完整电镀回路,有利于电镀时大电流的通过,进而提升电镀效率与大批量生产产品合格率。(The invention discloses a back structure of a double-sided P-type battery piece and a preparation method thereof. The invention of the structure enables the low-cost copper electroplating of the double-sided P-type cell to replace silver paste printing to be a simple and feasible process, and is beneficial to greatly reducing the production cost of the double-sided P-type cell.)

1. The utility model provides a back structure of two-sided P type battery piece which characterized in that: the aluminum-silicon-based composite material comprises a silicon substrate layer, wherein a passivation layer is arranged on the silicon substrate layer, an aluminum layer is arranged on the passivation layer, the aluminum layer can penetrate through the passivation layer to be in contact with the silicon substrate layer, an aluminum-silicon compound is generated on the aluminum layer at a high temperature, and a metal wire layer is arranged on the aluminum-silicon compound.

2. The back structure of a double-sided P-type battery piece of claim 1, wherein: the passivation layer is provided with continuous through holes, and the continuous through holes are in a grid shape.

3. The back structure of a double-sided P-type battery piece of claim 2, wherein: the area of the continuous through hole accounts for 2-98% of the surface area of the passivation layer.

4. The back structure of a double-sided P-type battery piece of claim 1, wherein: the passivation layer comprises at least one layer of aluminum oxide film and at least one layer of silicon nitride film.

5. The back structure of a double-sided P-type battery piece of claim 1, wherein: the metal conductor layer is provided with three layers, namely a nickel layer, a copper layer, a tin layer or a silver layer.

6. A preparation method of a back structure of a double-sided P-type battery piece is characterized by comprising the following steps: the method comprises the following steps:

s1, disposing a passivation layer: sequentially arranging at least an alumina film layer and at least a silicon nitride film layer on the silicon substrate layer, wherein the two film layers form a passivation layer;

s2, providing a continuity via: using laser to act on the passivation layer above the passivation layer, enabling the laser to burn through the passivation layer and expose the silicon substrate layer, enabling the laser to continuously work on the passivation layer, and enabling the burned-through pattern to be a continuous through hole;

s3, providing an aluminum layer: arranging an aluminum layer on the continuous through hole, wherein the aluminum layer is in contact with the silicon substrate layer;

s4, formation of aluminum silicon compound: the finished product in the last step is burnt for 30-60 minutes in the environment of 500-800 ℃ to obtain the aluminum-silicon compound;

s5, arranging a metal conductive layer: a metal lead layer is arranged on the aluminum-silicon compound, and the metal lead layer is provided with three layers, namely a nickel layer, a copper layer, a tin layer or a silver layer.

7. The preparation method of the back structure of the double-sided P-type battery piece as claimed in claim 6, wherein the preparation method comprises the following steps: the aluminum layer in S3 is provided by printing, metal sputtering or metal evaporation.

8. The preparation method of the back structure of the double-sided P-type battery piece as claimed in claim 6, wherein the preparation method comprises the following steps: the line width of the aluminum layer in S3 can completely cover the continuous via hole on the passivation layer, and the aluminum layer is higher than the passivation layer and is not higher than 3 um.

9. The method for preparing the back structure of the double-sided P-type battery piece as claimed in claim 8, wherein the method comprises the following steps: in S4-S5, an aluminum layer removing step is further provided to make the aluminum layer and the passivation layer at the same height.

10. The preparation method of the back structure of the double-sided P-type battery piece as claimed in claim 6, wherein the preparation method comprises the following steps: in S5, a metal wiring layer is provided by electroplating.

Technical Field

The invention relates to the field of photovoltaic cells, in particular to a novel back structure of a double-sided P-type cell piece and a preparation method thereof.

Background

With the continuous expansion and rapid development of the photovoltaic industry, since the first proposal of the bifacial P-type cell by ISFH (Hamelin solar research institute in Germany) and SolarWorld (a photovoltaic industry company located in Germany) in 2015, the bifacial P-type cell technology has been rapidly adopted by solar cell manufacturers. The rapid commercial application of double-sided P-type cells is mainly benefited by having a manufacturing process very similar to that of single-sided PERC cells, which is just the mainstream technology in the photovoltaic industry today. In the existing P-type cell, the front surface of the cell still adopts printing silver paste, and the back surface of the cell respectively uses a large amount of aluminum paste and silver-aluminum paste to manufacture grid lines; the silver paste, the silver-aluminum paste and the aluminum paste account for more than 25% of the total cost of producing the photovoltaic cell, and obviously, for a double-sided P-type cell, if the cheap metal can be used for replacing part or even all of the silver paste, the silver-aluminum paste and the aluminum paste, the method has a remarkable significance in reducing the production cost of the crystalline silicon photovoltaic cell.

However, in the existing P-type cell technology, the back surface of the cell adopts discontinuous laser openings, so that only aluminum-metal silicide (AlSix) can be formed locally, and a complete electric contact path cannot be formed during the electroplating process; secondly, because the porous structure (refer to the attached drawing) is formed after the aluminum paste printing and sintering, when the electroplating process is carried out, a large amount of electroplating liquid medicine can not only damage the lead welding points formed by silver-aluminum paste printing on the back surface of the double-sided P-type battery, but also seal the residual electroplating liquid medicine in the porous structure, and form unpredictable negative effects on the quality and the reliability of the battery.

Therefore, the present inventors, aiming at the above technical problems, aim to invent a back structure of a double-sided P-type cell and a method for manufacturing the same.

Disclosure of Invention

In order to overcome the above disadvantages, the present invention provides a back structure of a double-sided P-type cell and a method for manufacturing the same.

In order to achieve the above purposes, the invention adopts the technical scheme that: the back structure of the double-sided P-type battery piece comprises a silicon substrate layer, wherein a passivation layer is arranged on the silicon substrate layer, an aluminum layer is arranged on the passivation layer and can penetrate through the passivation layer to be in contact with the silicon substrate layer, the aluminum layer generates an aluminum-silicon compound at high temperature, and a metal lead layer is arranged on the aluminum-silicon compound.

Preferably, the passivation layer is provided with continuous through holes, and the continuous through holes are in a grid shape. The aluminum layer is conveniently arranged through the latticed continuous through holes, so that the aluminum layer and the silicon substrate layer are conveniently reacted, and the aluminum-silicon compound is generated.

Preferably, the area of the continuous through hole accounts for 2-98% of the surface area of the passivation layer. The area of the aluminum-silicon compound is ensured, and the conductivity is ensured.

Preferably, the passivation layer comprises at least one aluminum oxide film layer and at least one silicon nitride film layer. I.e. the passivation layer is aluminium oxide (Al)₂O₃) The film layer and the silicon nitride (SiNx) film layer form a passivation layer to ensure the protection of the silicon substrate layer.

Preferably, the metal conductor layer is provided with three layers, namely a nickel layer, a copper layer, a tin layer or a silver layer. Namely, the nickel layer is directly contacted with the aluminum-silicon compound layer, and the tin layer and the silver layer can be selected alternatively according to the requirement.

A preparation method of a back structure of a double-sided P-type battery piece comprises the following steps:

s1, disposing a passivation layer: sequentially arranging at least an alumina film layer and at least a silicon nitride film layer on the silicon substrate layer, wherein the two film layers form a passivation layer; the passivation layer is mainly deposited by means of vapor deposition.

S2, providing a continuity via: using laser to act on the passivation layer above the passivation layer, enabling the laser to burn through the passivation layer and expose the silicon substrate layer, enabling the laser to continuously work on the passivation layer, and enabling the burned-through pattern to be a continuous through hole;

s3, providing an aluminum layer: arranging an aluminum layer on the continuous through hole, wherein the aluminum layer is in contact with the silicon substrate layer;

s4, formation of aluminum silicon compound: the finished product in the last step is burnt for 30-60 minutes in the environment of 500-800 ℃ to obtain the aluminum-silicon compound;

s5, arranging a metal conductive layer: a metal lead layer is arranged on the aluminum-silicon compound, and the metal lead layer is provided with three layers, namely a nickel layer, a copper layer, a tin layer or a silver layer.

Preferably, the aluminum layer in S3 is provided by printing, metal sputtering or metal evaporation.

Preferably, the line width of the aluminum layer in S3 can completely cover the continuous via hole on the passivation layer, and the aluminum layer is higher than the passivation layer and is not higher than 3 um. In the case of an aluminum layer grown by metal sputtering or metal deposition, the thickness of the aluminum layer does not exceed 990nm, and thus the thickness is not easily grasped in printing, and the thickness is easily grasped by metal sputtering or metal deposition, which reduces the range.

Preferably, in S4-S5, an aluminum layer removing step is further provided to make the aluminum layer and the passivation layer at the same height. Thereby facilitating the arrangement of the subsequent metal wire layer.

Preferably, the metal wiring layer is provided by electroplating in S5. And simultaneously electroplating the other side of the P-type cell piece while electroplating the metal lead layer.

The back structure of the double-sided P-type battery piece has the advantages that the structure enables low-cost electroplated copper of the double-sided P-type battery piece to replace silver paste printing to be a simple and feasible process, production cost of the double-sided P-type battery piece is greatly reduced, and meanwhile, due to the fact that electroplated copper replaces screen printing silver paste, light receiving area can be increased, Filling Factor (FF) is improved, and power generation efficiency of the whole battery is improved.

The preparation method of the back structure of the double-sided P-type battery piece has the advantages that the aluminum-silicon compound is formed, so that the back of the battery can form a good electric contact path with a cathode when double-sided electroplating of the battery piece is carried out, the situation that a complete electroplating loop cannot be formed due to too high impedance is avoided, the passing of large current during electroplating is facilitated, and the electroplating efficiency and the qualification rate of mass production products are improved.

Drawings

Fig. 1 is a schematic diagram of a first step of a method for preparing a back structure of a double-sided P-type cell.

Fig. 2 is a schematic diagram of a second step of the method for preparing the back structure of the double-sided P-type cell.

Fig. 3 is a schematic diagram of a third step of the method for preparing the back structure of the double-sided P-type cell.

Fig. 4 is a schematic illustration of the removal of the aluminum layer after the production of the aluminum silicon compound.

Fig. 5 is a schematic diagram of a fifth step of the method for preparing the back structure of the double-sided P-type cell.

In the figure:

1-silicon substrate layer, 2-passivation layer, 3-aluminum layer, 4-aluminum silicon compound, 5-metal conductor layer, 6-continuous through hole,

21-alumina film layer, 22-silicon nitride film layer,

51-nickel layer, 52-copper layer, 53-silver layer.

Detailed Description

The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.

Referring to the attached drawings 1-5, the back structure of the double-sided P-type battery piece in the embodiment comprises a silicon substrate layer 1, a passivation layer 2 is arranged on the silicon substrate layer 1, an aluminum layer 3 is arranged on the passivation layer 2, the aluminum layer 3 can penetrate through the passivation layer 2 to be in contact with the silicon substrate layer 1, the aluminum layer 3 generates an aluminum-silicon compound 4 at a high temperature, and a metal lead layer 5 is arranged on the aluminum-silicon compound 4.

The passivation layer 2 is provided with continuous through holes 6, and the continuous through holes 6 are in a grid shape. The aluminum layer 3 is convenient to be arranged through the latticed continuous through holes 6, and then the aluminum layer 3 and the silicon substrate layer 1 are convenient to react to generate the aluminum-silicon compound 4.

The area of the continuous via 6 occupies 2-98% of the surface area of the passivation layer 2. Namely, the area of the aluminum-silicon compound 4 is ensured, and the conductivity is ensured.

The passivation layer 2 includes at least one alumina film layer 21 and at least one silicon nitride film layer 22. Namely, the passivation layer 2 is composed of an aluminum oxide (Al2O3) film layer and a silicon nitride (SiNx) film layer, and the passivation layer 2 is formed to ensure the protection of the silicon substrate layer 1.

The metal conductor layer 5 is provided with three layers, namely a nickel layer 51, a copper layer 52 and a tin layer or silver layer 53 in sequence. I.e. the nickel layer 51 is in direct contact with the layer of aluminium-silicon compound 4 and the tin or silver layer 53 may be alternative according to requirements.

A preparation method of a back structure of a double-sided P-type battery piece comprises the following steps:

s1, disposing passivation layer 2: at least an alumina film layer 21 and at least a silicon nitride film layer 22 are sequentially arranged on the silicon substrate layer 1, and the two film layers form a passivation layer 2; the passivation layer 2 is arranged mainly by means of vapour deposition. See fig. 1 for a description.

S2, providing the continuity through-holes 6: using laser to act on the passivation layer 2 above the passivation layer 2, wherein the laser can burn through the passivation layer 2 and expose the silicon substrate layer 1, and the laser performs continuous work on the passivation layer 2 and burns through the continuous through hole 6 with the pattern, as shown in fig. 2;

s3, providing aluminum layer 3: arranging an aluminum layer 3 on the continuous through hole 6, wherein the aluminum layer 3 is in contact with the silicon substrate layer 1, and the figure 3 is shown;

s4, formation of alumino-silicon compound 4: the finished product in the last step is sintered for 30-60 minutes under the environment of 500-800 ℃ to obtain an aluminum-silicon compound 4;

s5, arranging a metal conductive layer: a metal wire layer 5 is provided on the aluminum-silicon compound 4, and the metal wire layer 5 is provided with three layers, namely a nickel layer 51, a copper layer 52, and a tin layer or a silver layer 53 in sequence, as shown in fig. 5.

In S3, the aluminum layer 3 is provided by printing, metal sputtering or metal evaporation.

The line width of the aluminum layer 3 in S3 can completely cover the continuous via 6 on the passivation layer 2, and the aluminum layer 3 is higher than the passivation layer 2 and is not higher than 3 um. In the case of the aluminum layer 3 grown by the metal sputtering or metal deposition method, the thickness of the aluminum layer 3 does not exceed 2990nm, which is not easy to be grasped in printing, but the thickness is easy to be grasped by the metal sputtering or metal deposition method, and therefore, the range is narrowed, as shown in fig. 3.

In S4-S5, a step of removing the aluminum layer 3 is further provided such that the aluminum layer 3 is at the same height as the passivation layer 2. I.e. to facilitate the arrangement of the subsequent metal conductor layer 5, see fig. 4.

In S5, the metal wiring layer 5 is provided by electroplating. The other side of the P-type cell piece can be simultaneously electroplated while the metal lead layer 5 is electroplated.

The back structure of the double-sided P-type cell has the advantages that the invention of the structure enables the low-cost electroplated copper of the double-sided P-type cell to replace silver paste printing to be a simple and feasible process, and is beneficial to greatly reducing the production cost of the double-sided P-type cell.

The preparation method of the back structure of the double-sided P-type battery piece has the advantages that the aluminum-silicon compound 4 is formed, so that the back of the battery can form a good electric contact path with a cathode when double-sided electroplating of the battery piece is carried out, the situation that a complete electroplating loop cannot be formed due to too high impedance is avoided, the passing of large current during electroplating is facilitated, and the electroplating efficiency and the qualification rate of mass production products are improved.

Moreover, when the double-sided P-type photovoltaic cell adopting the structure is subjected to a double-sided electroplating process, the back surface of the cell piece is guaranteed to be damaged by electroplating liquid medicine when the electroplating process is carried out through double-sided horizontal electroplating equipment, or the liquid medicine is caused to remain in a porous structure of the back surface, so that the quality and the reliability of the cell piece are affected by uncertain negative effects.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the present invention is not limited thereto, and any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of the present invention.