阅读说明：本技术 一种太阳能电池的光注入钝化方法 (Light injection passivation method of solar cell ) 是由 刘娟 乐雄英 孔金辉 于 2021-08-04 设计创作，主要内容包括：本发明公开一种太阳能电池的光注入钝化方法,对金属化烧结后的太阳能电池进行光注入并辅以加热以实现钝化,包括如下步骤：(1)在常压下,对太阳能电池进行光注入,光注入的辐射强度为10-25suns,光注入时间为100-300秒；(2)在对太阳能电池进行光注入的同时辅以加热以实现钝化；加热过程包括：加热阶段、降温阶段和保温阶段；加热阶段是：将太阳能电池加热至表面温度为第一温度；降温阶段是：将太阳能电池的表面温度从第一温度降至第二温度；保温阶段是：将太阳能电池在第二温度下进行保温；第一温度为300-650℃；第二温度为200-250℃。本发明的钝化方法,能够解决电注入方法中存在的产量低,均匀性差,容易出现效率提升不稳定的问题,本发明的方法实施过程简单。(The invention discloses a light injection passivation method of a solar cell, which is used for carrying out light injection on the metallized and sintered solar cell and assisting in heating to realize passivation and comprises the following steps: (1) under normal pressure, light injection is carried out on the solar cell, the radiation intensity of the light injection is 10-25suns, and the light injection time is 100 seconds and 300 seconds; (2) heating is assisted while light injection is carried out on the solar cell so as to realize passivation; the heating process comprises the following steps: a heating stage, a cooling stage and a heat preservation stage; the heating stage is as follows: heating the solar cell to a surface temperature of a first temperature; the cooling stage is as follows: reducing the surface temperature of the solar cell from a first temperature to a second temperature; the heat preservation stage is as follows: insulating the solar cell at a second temperature; the first temperature is 300-650 ℃; the second temperature is 200-250 ℃. The passivation method can solve the problems of low yield, poor uniformity and unstable efficiency improvement in the electric injection method, and the implementation process of the method is simple.)

1. A light injection passivation method of a solar cell is characterized in that light injection is carried out on the solar cell after metallization sintering, and heating is assisted to realize passivation, and the method specifically comprises the following steps:

(1) carrying out light injection on the solar cell under normal pressure, wherein the radiation intensity of the light injection is 10-25suns, and the time of the light injection is 100-300 seconds;

(2) heating is assisted while the solar cell is subjected to light injection to realize passivation; the heating process comprises the following steps: a heating stage, a cooling stage and a heat preservation stage;

the heating stage is as follows: heating the solar cell to a surface temperature of a first temperature;

the cooling stage is as follows: lowering the surface temperature of the solar cell from the first temperature to a second temperature;

the heat preservation stage is as follows: insulating the solar cell at the second temperature;

the first temperature is 300-650 ℃; the second temperature is 200-250 ℃.

2. The method as claimed in claim 1, wherein the radiation intensity of the light injection is 10-18suns, and the time of the light injection is 200-300 seconds; the first temperature is 300-550 ℃.

3. The method as claimed in claim 2, wherein the radiation intensity of the light injection is 14suns, and the time of the light injection is 250-300 s; the first temperature is 350-400 ℃.

4. The method of claim 1, wherein the solar cell is incubated at the second temperature for a period of time that is 40-60% of the light injection time.

5. The method for light injection passivation of the solar cell according to claim 1, wherein the solar cell sequentially transmits the single solar cells in a chain transmission manner during the light injection.

6. The method of claim 1, wherein the light injection passivation is performed by using an infrared light source or an LED light source.

7. The light injection passivation method for the solar cell as claimed in claim 1, wherein the heating is performed by a hot plate heating method.

Technical Field

The invention relates to the technical field of solar cells, in particular to a light injection passivation method of a solar cell, and particularly relates to a light injection passivation method of a P-type solar cell.

Background

With the rapid development of solar cell technology, the development of high-efficiency cells is more and more emphasized, and in the current photovoltaic market, the solar cells successfully commercialized mainly include: crystalline silicon solar cells, gallium arsenide solar cells, cadmium telluride solar cells, thin film amorphous silicon solar cells, and copper indium selenide solar cells. Crystalline silicon solar cells occupy more than 80% of the solar photovoltaic market due to the advantages of relatively low cost, high conversion efficiency, good stability and the like, and the share can be continuously maintained for a long time, while perc cells are widely applied due to good passivation effect, low cost and large efficiency improvement space.

The tunneling oxide layer and the doped layer of the solar cell jointly form a passivation contact structure, and the structure provides good surface passivation for the back surface of the silicon wafer. However, in the prior art, the H passivation of the solar cell is usually realized by adopting an electrical injection method, that is, after the solar cell is placed in an electrical injection device, current is supplied to each station to achieve the electrical injection passivation effect. However, in the research, the solar cell has the problems of low yield, poor uniformity and unstable efficiency improvement in the process of passivation by using electric injection.

In the mechanism, after the Perc process, the carrier transmission distance is lengthened, the surface recombination rate is low after double-sided passivation, the volume life attenuation ratio is increased due to light-induced attenuation, back aluminum gettering is lacked, and the attenuation of a recombination center formed by enrichment of metal magazines is large.

Disclosure of Invention

The tunneling oxide layer and the doped layer of the solar cell jointly form a passivation contact structure, and the structure provides good surface passivation for the back surface of the silicon wafer. In the prior art, the H passivation of the solar cell is usually realized by adopting an electrical injection method, but in research, the problems that the yield of the solar cell is low, the uniformity is poor, and the efficiency improvement is unstable are easily caused in the process of adopting the electrical injection passivation.

The invention provides a light injection passivation method of a solar cell, aiming at the problems of low yield, poor uniformity and unstable efficiency improvement existing in the electric injection passivation.

The invention is realized by the following technical scheme:

a light injection passivation method of a solar cell is characterized in that light injection is carried out on the solar cell after metallization sintering, and heating is assisted to realize passivation, and the method comprises the following steps:

(1) carrying out light injection on the solar cell under normal pressure, wherein the radiation intensity of the light injection is 10-25suns, and the time of the light injection is 100-300 seconds;

(2) heating is assisted while the solar cell is subjected to light injection to realize passivation; the heating process comprises the following steps: a heating stage, a cooling stage and a heat preservation stage; the heating stage is as follows: heating the solar cell to a surface temperature of a first temperature; the cooling stage is as follows: lowering the surface temperature of the solar cell from the first temperature to a second temperature; the heat preservation stage is as follows: insulating the solar cell at the second temperature; the first temperature is 300-650 ℃; the second temperature is 200-250 ℃.

Specifically, the metallized solar cell refers to a solar cell in which a positive electrode and a negative electrode have been fabricated.

The light injection passivation method of the solar cell provided by the invention comprises the following steps: performing light injection on the metallized and sintered solar cell and heating to realize passivation; the radiation intensity of light injection under normal pressure is 10-18suns, and the time of light injection is 100-300 s. The auxiliary heating process comprises the following steps: the method comprises a heating stage, a cooling stage and a heat preservation stage, wherein the two temperature stages are total, the surface of the solar cell is firstly heated to a required temperature (a first temperature), then the temperature is reduced to a second temperature, and the heat preservation stage is that the solar cell is preserved at the second temperature. In the heating stage, the cooling stage and the heat preservation stage of the method, the light injection is kept all the time; light injection not only has high productivity, but also can improve injection strength, improve the BO attenuation and improve the HID at the same time, and the light injection can be combined with sintering to be integrally processed, so that one-time separation is reduced, the cost is reduced, and compared with a sheet transfer mode of electric injection stacking, the problem of light and dark sheets at the assembly end in batches is solved.

The principle that the light injection passivation method of the solar cell can realize passivation is as follows: in the heating stage and the cooling stage, the temperature plays a main role, and the H ions in the back film in the solar cell can be fully activated under the condition that the first temperature is 300-650 ℃; in the heat preservation stage, light injection plays a main role, and under the condition that the second temperature is 200-250 ℃, activated H ions are transferred from the back film to the crystalline silicon layer through the high energy of the light injection, so that the dangling bonds can be saturated by the activated H ions, and the interface passivation is completed.

Further, the radiation intensity of the light injection is 10-18suns, and the time of the light injection is 200-300 seconds; the first temperature is 300-550 ℃.

Further, the radiation intensity of the light injection is 14suns, and the time of the light injection is 250-300 s; the first temperature is 350-400 ℃.

Further, the solar cell is subjected to heat preservation at the second temperature, and the heat preservation time is 40-60% of the light injection time.

Further, the solar cells adopt a chain transmission mode to sequentially transmit the single solar cells in the light injection process.

Further, the light injection can be performed by using an infrared light source or an LED light source.

Further, the heating may be performed by a hot plate heating method.

Compared with the prior art, the light injection passivation method of the solar cell provided by the invention has the following beneficial effects:

(1) the light injection passivation method for the solar cell can further solve the problems of low yield, poor uniformity and unstable efficiency improvement in the electric injection method, and the implementation process of the method is simple.

(2) The light injection passivation method of the solar cell plays a main role in the temperature in the heating stage and the cooling stage, and can fully activate H ions in the back film of the solar cell under the condition that the first temperature is 300-650 ℃; the back film comprises back aluminum oxide and silicon nitride, or the back film comprises back aluminum oxide and silicon oxynitride, or the back film comprises back aluminum oxide, silicon nitride and silicon oxynitride; if the first temperature is too low, H ions in the solar cell cannot be well activated; if the first temperature is too high, it becomes secondary sintering that causes the metal region to be over-fired, thereby degrading the solar cell performance.

(3) In the light injection passivation method of the solar cell, the light injection plays a main role in the heat preservation stage (second temperature), the heat preservation is carried out at the temperature of 200-250 ℃, and activated H ions are transferred to the crystalline silicon layer through the high energy of the light injection to complete interface passivation; if the temperature in the heat preservation stage is too high, the alloy area is expanded, and the composite area is enlarged, so that the conversion efficiency of the solar cell is reduced; if the temperature in the heat preservation stage is too low, the activated H ions are changed into an inactivated state, so that the passivation of the solar cell cannot be completed by means of light injection, and the performance of the solar cell is reduced.

Drawings

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

Fig. 1 is a diagram of an apparatus for performing a light injection passivation method of a solar cell according to the present invention.

In the figure: the device comprises a feeding area 1, a heating area 2, a cooling area 3, a heat preservation area 4, a conveying wheel 5, a cooling fan 6, a discharging area 7, a heating device 21, a heat exhaust fan 31 and a heat preservation device 41.

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. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. 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.

Example 1

A light injection passivation method of a solar cell is used for carrying out light injection on the solar cell after metallization sintering and assisting heating to realize passivation, and specifically comprises the following steps:

(1) carrying out light injection on the solar cell under normal pressure, wherein the radiation intensity of the light injection is 10suns, and the time of the light injection is 150 seconds;

(2) the solar cell is subjected to light injection and simultaneously assisted with heating so as to realize passivation of the solar cell; and the heating process comprises: a heating stage, a cooling stage and a heat preservation stage; the heating stage is as follows: heating the solar cell to a surface temperature of 400 ℃ (first temperature); the cooling stage is as follows: reducing the surface temperature of the solar cell from 400 ℃ to 200 ℃ (second temperature); the heat preservation stage is as follows: and (3) preserving the heat of the solar cell at the temperature of 200 ℃ (second temperature) for 80 seconds to realize the passivation of the solar cell.

Preferably, in the process of light injection, the solar cells in embodiment 1 adopt a chain transmission mode to sequentially transmit the single solar cells; the light injection can adopt an infrared light source; the heating can be carried out by a hot plate heating method.

Specifically, the passivation method of example 1 can adopt the implementation apparatus shown in fig. 1 to perform light injection passivation on the solar cell, and the operation process is as follows: under normal pressure, solar cells are fed from a feeding area 1, and are conveyed into a heating area 2 through a conveying wheel 5 (a crawler belt is arranged on the conveying wheel); the cell is light-injected by means of an infrared light source, while the surface of the solar cell is heated to 400 ℃ (first temperature) by means of a heating device 21 (hot plate heating); then, the heated solar cells are continuously conveyed into the cooling zone 3 by the conveying wheel 5, and the air is exhausted by the heat exhaust fan 31, so that the surface temperature of the solar cells is reduced from 400 ℃ to 200 ℃ (second temperature); then the solar cell enters a heat preservation area 4, and the solar cell is maintained at the temperature of 200 ℃ for 80 seconds by a heat preservation device 41, so that the passivation of the solar cell is completed; finally, the material is discharged from a discharging area 7 after being cooled by a cooling fan 6.

Example 2

A light injection passivation method of a solar cell is used for carrying out light injection on the solar cell after metallization sintering and assisting heating to realize passivation, and specifically comprises the following steps:

(1) carrying out light injection on the solar cell under normal pressure, wherein the radiation intensity of the light injection is 14suns, and the time of the light injection is 200 seconds;

(2) the solar cell is subjected to light injection and simultaneously assisted with heating so as to realize passivation of the solar cell; and the heating process comprises: a heating stage, a cooling stage and a heat preservation stage; the heating stage is as follows: heating the solar cell to a surface temperature of 550 ℃ (first temperature); the cooling stage is as follows: reducing the surface temperature of the solar cell from 550 ℃ to 220 ℃ (second temperature); the heat preservation stage is as follows: and (3) preserving the heat of the solar cell at the temperature of 220 ℃ (second temperature) for 100 seconds to realize the passivation of the solar cell.

Preferably, in the above embodiment 2, the solar cells sequentially transmit the single solar cells in a chain transmission manner during the light injection process; the light injection can adopt an LED light source; the heating can be carried out by a hot plate heating method.

Example 3

A light injection passivation method of a solar cell is used for carrying out light injection on the solar cell after metallization sintering and assisting heating to realize passivation, and specifically comprises the following steps:

(1) carrying out light injection on the solar cell under normal pressure, wherein the radiation intensity of the light injection is 14suns, and the time of the light injection is 250 seconds;

(2) the solar cell is subjected to light injection and simultaneously assisted with heating so as to realize passivation of the solar cell; and the heating process comprises: a heating stage, a cooling stage and a heat preservation stage; the heating stage is as follows: heating the solar cell to a surface temperature of 350 ℃ (first temperature); the cooling stage is as follows: reducing the surface temperature of the solar cell from 350 ℃ to 230 ℃ (second temperature); the heat preservation stage is as follows: and (3) insulating the solar cell at the 230 ℃ (second temperature) for 120 seconds to realize the passivation of the solar cell.

Preferably, in the above embodiment 3, the solar cells sequentially transmit the single solar cells in a chain transmission manner during the light injection process; the light injection can adopt an LED light source; the heating can be carried out by a hot plate heating method.

Example 4

A light injection passivation method of a solar cell is used for carrying out light injection on the solar cell after metallization sintering and assisting heating to realize passivation, and specifically comprises the following steps:

(1) carrying out light injection on the solar cell under normal pressure, wherein the radiation intensity of the light injection is 18suns, and the time of the light injection is 300 seconds;

(2) the solar cell is subjected to light injection and simultaneously assisted with heating so as to realize passivation of the solar cell; and the heating process comprises: a heating stage, a cooling stage and a heat preservation stage; the heating stage is as follows: heating the solar cell to a surface temperature of 650 ℃ (first temperature); the cooling stage is as follows: reducing the surface temperature of the solar cell from 650 ℃ to 250 ℃ (second temperature); the heat preservation stage is as follows: and (3) preserving the heat of the solar cell for 180 seconds at the temperature of 250 ℃ (second temperature) to realize the passivation of the solar cell.

Preferably, in the above embodiment 4, the solar cells sequentially transmit the single solar cells in a chain transmission manner during the light injection process; the light injection can adopt an infrared light source; the heating can be carried out by a hot plate heating method.

Comparative example 1

A light injection passivation method of a solar cell is used for carrying out light injection on the solar cell after metallization sintering and assisting heating to realize passivation, and specifically comprises the following steps:

(1) carrying out light injection on the solar cell under normal pressure, wherein the radiation intensity of the light injection is 14suns, and the time of the light injection is 250 seconds;

(2) the solar cell is subjected to light injection and simultaneously assisted with heating so as to realize passivation of the solar cell; and the heating process comprises: a heating stage, a cooling stage and a heat preservation stage; the heating stage is as follows: heating the solar cell to a surface temperature of 250 ℃ (first temperature); the cooling stage is as follows: reducing the surface temperature of the solar cell from 250 ℃ to 230 ℃ (second temperature); the heat preservation stage is as follows: and (3) insulating the solar cell at the 230 ℃ (second temperature) for 120 seconds to realize the passivation of the solar cell.

Preferably, the solar cells in comparative example 1 adopt a chain transmission mode to sequentially transmit the single solar cells in the light injection process; the light injection can adopt an LED light source; the heating can be carried out by a hot plate heating method.

The difference between the above comparative example 1 and example 3 is that the first temperature is different, the rest of the passivation conditions are the same, and the first temperature in comparative example 1 is lower than that in example 3.

Comparative example 2

Comparative example 2 differs from example 3 above in that the first temperature is different and the rest of the passivation conditions are the same, and the first temperature in comparative example 2 is 700 c higher than in example 3.

Comparative example 3

Comparative example 3 differs from example 3 above in that the second temperature is different and the rest of the passivation conditions are the same, and the second temperature in comparative example 3 is 150 c, which is lower than example 3.

Comparative example 4

Comparative example 4 differs from example 3 above in that the second temperature is different and the rest of the passivation conditions are the same, and the second temperature in comparative example 4 is 300 c higher than in example 3.

And (3) testing: the solar cells passivated according to the above examples 1 to 4 and comparative examples 1 to 4 were subjected to electrical property tests, and the test results are shown in table 1:

the test results of the above examples 1 to 4 show that the solar cell light injection passivation method of the invention can well complete the passivation process of the solar cell and has stable efficiency. It can be seen from the test results of comparative examples 1-4 that either an excessively high or low first temperature or an excessively high or low second temperature is not favorable for cell passivation, which may degrade the electrical performance of the solar cell.

The above-mentioned preferred embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention. Obvious variations or modifications of the present invention are within the scope of the present invention.