CN106449779B - A kind of photovoltaic cell of high temperature resistance high humidity environment - Google Patents

Abstract

The invention relates to a photovoltaic cell resistant to high temperature and high humidity environment, which belongs to the field of solar photovoltaic power generation production. At present, there is no high-reliability, economical, portable and practical photovoltaic cell that can solve the problem of the decrease in photoelectric conversion rate caused by the PID effect caused by the high-temperature and high-humidity environment. The invention includes a crystalline silicon substrate, the front and back of the crystalline silicon substrate are coated with a layer of anti-reflection film, and the feature is that: the edge of the silicon wafer of the crystalline silicon substrate is coated with a layer of edge protection film, and the edge The protective film is connected to the anti-reflection film, and the crystalline silicon substrate is completely sealed through the edge protective film and the anti-reflection film so that the crystalline silicon substrate is completely isolated from the external environment. The invention has reasonable structure design, strong reliability, good economy, lightness and practicality, and can effectively solve the problem of photoelectric conversion rate decrease caused by PID effect caused by high temperature and high humidity environment.

Description

A photovoltaic cell resistant to high temperature and high humidity environment

technical field

The invention relates to a photovoltaic cell resistant to high-temperature and high-humidity environments, belonging to the field of solar photovoltaic power generation production, and is specifically used for improving the performance of photovoltaic cells and improving the ability to resist the PID effect caused by high-temperature and high-humidity environments.

Background technique

Solar photovoltaic cells are devices that directly convert light energy into electrical energy through the photovoltaic effect. Crystalline silicon photovoltaic cells account for the vast majority of photovoltaic cell production due to their high conversion efficiency, stable performance, and moderate price. They have been put into use in many commercial power stations, and their effects are significantly better than other types of photovoltaic cells.

However, with the expansion of applications, from the ground to the roof, from agricultural greenhouses to fish ponds and tidal flats, crystalline silicon photovoltaic cells have also encountered some problems, especially in high temperature and humid environments, prone to PID effects, making the performance of photovoltaic cells rapidly decay . At present, the production process of photovoltaic cells generally does not take into account the applicable occasions, and only uses the initial conversion efficiency index as the basis for judgment; while in the stage of making modules, double-sided glass interlayers are used to reduce the impact of moisture on the cells. Although double-glass modules do play a certain role in resisting high-temperature and high-humidity environments, double-glass modules need to use glass on both sides, which not only increases their own cost, but also increases the cost of brackets and foundations due to increased weight. Coupled with the need to make certain changes to the module production line, the cost of double-glass modules has always been much higher than that of traditional modules. Although there are some other technologies used to reduce the impact of moisture on the battery sheet, such as the Chinese patent with the publication date of April 29, 2015 and the publication number CN104576796A, which discloses a protective film on the back of the photovoltaic module, but the photovoltaic module It is also difficult for the protective film on the back of the module to effectively solve the problem of the decrease in photoelectric conversion rate caused by the PID effect caused by the high temperature and high humidity environment.

To sum up, there is currently no photovoltaic cell with high reliability, good economy, lightness and practicality that can solve the problem of the decrease of photoelectric conversion rate caused by the PID effect caused by the high temperature and high humidity environment.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art, and provide a kind of reasonable structure design, strong reliability, good economy, light and practical, and can effectively solve the PID effect caused by high temperature and high humidity environment at the same time. Photovoltaic cells resistant to high-temperature and high-humidity environments with the problem of photoelectric conversion rate decline.

The technical solution adopted by the present invention to solve the above problems is: the photovoltaic cell resistant to high temperature and high humidity environment includes a crystalline silicon substrate, the front and back of the crystalline silicon substrate are coated with an anti-reflection film, and its structural characteristics are: The edge of the silicon wafer of the crystalline silicon substrate is coated with a layer of edge protection film, and the edge protection film is connected to the anti-reflection film, and the crystalline silicon substrate is completely sealed together by the edge protection film and the anti-reflection film to make the crystalline silicon substrate Completely isolated from the outside environment.

Preferably, the material of the antireflection film in the present invention is silicon nitride.

Preferably, the thickness of the antireflection film in the present invention is 140 nanometers.

Preferably, the material of the edge protection film in the present invention is silicon nitride.

Preferably, the surface of the edge of the silicon wafer in the present invention is jagged or pyramidal.

As a preference, the process of coating the edge protection film of the present invention is as follows: when the process flow of the solar cell reaches the step of coating the anti-reflection film, it will be carried out in a vacuum environment, and the plasma-enhanced chemical vapor deposition method will be used on the crystal silicon A layer of anti-reflection film is coated on the substrate, and the thickness of the anti-reflection film is 140 nanometers; because the position at the edge of the silicon wafer is special compared to the front and back of the crystalline silicon substrate, the plasma-enhanced chemical vapor deposition method is coated on the edge of the silicon wafer. The anti-reflection film is not as dense as the front and back of the crystalline silicon substrate. The anti-reflection film on the edge of the silicon wafer forms a porous and loose structure, which makes it easy for water and air in the external environment to enter, resulting in a decrease in the efficiency and performance of the solar cell. Worsening situation; after the plasma-enhanced chemical vapor deposition method, continue to stack multiple solar cells in a vacuum environment, then move to another vacuum chamber, evacuate to a vacuum, and first bombard the edge of the silicon wafer with high-energy particles Cleaning, remove the loose anti-reflection film on the edge of the silicon wafer, and further eliminate the influence of the diffused impurities on the edge of the silicon wafer on the performance of the battery, and form a layer of jagged or pyramid-shaped surface, which is beneficial to the newly plated edge protection film Attached to the edge of the silicon wafer; then use the physical vapor deposition method to coat a dense edge protection film on the edge of the silicon wafer.

Preferably, the vacuum degree of the high-energy particle bombardment cleaning in the present invention is higher than that of the plasma-enhanced chemical vapor deposition method.

Preferably, the physical vapor deposition method of the present invention adopts the magnetron sputtering method.

Preferably, the vacuum degree of the present invention is lower than 0.1 Pa when the edge protection film is plated.

Preferably, after a plurality of solar cell sheets of the present invention are stacked, the edges of the silicon sheets in all crystalline silicon substrates are flush.

Compared with the prior art, the present invention has the following advantages and effects: the edge of the silicon wafer of the crystalline silicon substrate is coated with a layer of edge protection film, which replaces the original loose silicon nitride film, and protects the internal and external environment of the cell. The water vapor in the air is completely isolated from the air, which reduces the possibility of PID effect in high temperature and high humidity environment. In addition, the bombardment of high-energy particles removes the shallowly diffused silicon base at the edge, forming a jagged edge, which reduces the chance of leakage at the edge of the cell, improves the photoelectric conversion efficiency, and further improves the performance of the cell, especially in terms of anti-PID effect. superior. The produced photovoltaic cells can be directly entered into the downstream production process without changing other parts of the production line.

Description of drawings

Fig. 1 is a schematic structural diagram of a photovoltaic cell resistant to high temperature and high humidity environment in an embodiment of the present invention.

In the figure: 1—crystalline silicon substrate; 2—anti-reflection film; 3—edge protection film; 4—edge of silicon wafer.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. The following examples are explanations of the present invention and the present invention is not limited to the following examples.

Example.

Referring to Fig. 1, the photovoltaic cell resistant to high temperature and high humidity environment in this embodiment comprises a crystalline silicon substrate 1, and the front and back sides of the crystalline silicon substrate 1 are coated with a layer of anti-reflection film 2, and the silicon wafer of the crystalline silicon substrate 1 The edge 4 is coated with a layer of edge protection film 3, the edge protection film 3 is connected with the anti-reflection film 2, and the crystal silicon substrate 1 is completely sealed by the edge protection film 3 and the anti-reflection film 2 so that the crystal silicon substrate 1 is separated from the external environment. Complete isolation can effectively solve the problem of photoelectric conversion rate drop caused by PID effect caused by high temperature and high humidity environment, and it has high reliability, good economy, light and practical.

The material of the anti-reflection film 2 in this embodiment can be silicon nitride. The thickness of the anti-reflection film 2 can be 140 nanometers, that is, controlled to be approximately equal to 1/4 wavelength of the peak value of the solar radiation spectrum. The material of the edge protection film 3 can be silicon nitride, or other materials with better performance can be selected as the protective film layer. The surface of the edge 4 of the silicon wafer is usually jagged or pyramidal.

In this embodiment, the process of coating the edge protection film 3 is as follows: when the process flow of the solar cell reaches the step of coating the anti-reflection film 2, it will be carried out in a vacuum environment, and the plasma enhanced chemical vapor deposition method (PECVD) will be used. ) Coating a layer of anti-reflection film 2 on the crystalline silicon substrate 1, the thickness of the anti-reflection film 2 is 140 nanometers; because the position at the edge 4 of the silicon wafer is special compared to the front and back of the crystalline silicon substrate 1, resulting in plasma enhanced chemical The anti-reflection film 2 plated on the edge 4 of the silicon wafer by vapor phase deposition (PECVD) is not as dense as the front and back sides of the crystalline silicon substrate 1, and the anti-reflection film 2 on the edge 4 of the silicon wafer forms a porous and loose structure, so that Water and air in the external environment are easy to enter, resulting in a decrease in the efficiency and performance of solar cells; after the end of the plasma enhanced chemical vapor deposition (PECVD), continue to stack multiple solar cells in a vacuum environment for Carry out concentrated treatment, then move to another vacuum chamber, evacuate to vacuum, first perform high-energy particle bombardment cleaning on the edge 4 of the silicon wafer, remove the loose anti-reflection film 2 on the edge 4 of the silicon wafer, and further eliminate the edge 4 of the silicon wafer. The impact of diffusion impurities on battery performance, and a layer of jagged or pyramid-shaped surface is formed, which is conducive to the adhesion of the newly plated edge protection film 3 to the edge 4 of the silicon wafer, and improves the combination of the new coating layer and the crystalline silicon substrate 1 ; Then use physical vapor deposition (PVD) to coat a layer of dense edge protection film 3 on the edge 4 of the silicon wafer.

In this embodiment, the vacuum degree during the high-energy particle bombardment cleaning is higher than that of the plasma-enhanced chemical vapor deposition (PECVD) method. Physical vapor deposition (PVD) uses magnetron sputtering, and other PVD methods can also be used. The vacuum degree when plating the edge protection film 3 is lower than 0.1 Pa. After a plurality of solar cell sheets are stacked, the edges 4 of the silicon sheets in all the crystalline silicon substrates 1 are flush with each other.

On the basis of the conventional crystalline silicon solar photovoltaic cell structure, a dense film is formed on the edge 4 of the silicon wafer as the edge protection film 3, completely isolating the crystalline silicon substrate 1 from the external environment, so as to reduce the impact of the surrounding environment on the performance of the cell , especially in the PID effect caused by high temperature and high humidity environment, there is a significant improvement. In the conventional production process of photovoltaic cells, after PECVD plating silicon nitride anti-reflection film, continue to add a process in vacuum; stack solar cells, and in the case of higher vacuum, the cells The edge is processed to remove the loose silicon nitride and the shallowly diffused silicon substrate on the edge of the cell, and then a denser protective film is formed on the silicon substrate by physical vapor deposition (PVD), replacing the original process on the cell The loose silicon nitride film layer formed at the edge; after completing this new process, continue to enter the production process of conventional photovoltaic cells.

In addition, it should be noted that the specific embodiments described in this specification may be different in parts, shapes and names of parts, and the above content described in this specification is only an illustration of the structure of the present invention. All equivalent changes or simple changes made according to the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims. All should belong to the protection scope of the present invention.

Claims (9)

1. a kind of photovoltaic cell of high temperature resistance high humidity environment, including crystalline silicon substrate, the front and back of the crystalline silicon substrate plate There is one layer of antireflective coating, it is characterised in that：The silicon chip edge of the crystalline silicon substrate is coated with one layer of edge-protected film, and the edge is protected Cuticula is connected with antireflective coating, and crystalline silicon substrate is fully sealed into crystal silicon jointly by edge-protected film and antireflective coating Substrate is thoroughly isolated with external environment；The technique for being coated with edge-protected film is as follows：Plating is gone in solar battery sheet technological process When this link of antireflective coating processed, it can carry out under vacuum conditions, using plasma-enhanced chemical vapor deposition PECVD method in crystalline substance One layer of antireflective coating is plated on silicon chip, the thickness of antireflective coating is 140 nanometers；Terminating plasma-enhanced chemical vapor deposition PECVD method Afterwards, continue that multi-disc solar battery sheet stacks up under vacuum conditions, then move on to other vacuum chamber, be evacuated to vacuum, High-energy particle bombardment cleaning first is carried out to silicon chip edge, the loose antireflective coating of silicon chip edge be purged, and further disappears Except influence of the silicon chip edge diffusion impurity to battery performance, and the surface of one layer of zigzag or pyramid is formd, be advantageous to The edge-protected film being newly coated with is attached to silicon chip edge；Then it is fine and close in silicon chip edge plating last layer using physical vaporous deposition Edge-protected film.

2. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：The material of the antireflective coating Matter is silicon nitride.

3. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：The thickness of the antireflective coating Spend for 140 nanometers.

4. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：The edge-protected film Material is silicon nitride.

5. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：The table of the silicon chip edge Face is zigzag or pyramid.

6. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：High-energy particle bombardment cleans When vacuum be higher than plasma-enhanced chemical vapor deposition PECVD method vacuum.

7. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：Physical vaporous deposition is adopted Use magnetron sputtering method.

8. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：When being coated with edge-protected film Vacuum be less than 0.1 pa.

9. the photovoltaic cell of high temperature resistance high humidity environment according to claim 1, it is characterised in that：Multi-disc solar battery sheet After stacking up, the silicon chip edge in all crystalline silicon substrates is flush.