阅读说明：本技术 光伏电池印刷不良片的回收方法及返工方法 (Recovery method and reworking method of poor printed sheet of photovoltaic cell ) 是由 付昊鑫 杜俊霖 陈红元 孟凡英 刘正新 于 2021-10-26 设计创作，主要内容包括：本发明涉及一种光伏电池印刷不良片的回收方法和返工方法,包括如下步骤：将光伏电池印刷不良片分别进行热处理和第一酸洗处理,以去除光伏电池印刷不良片表面的树脂、电极和透明导电氧化物薄膜,得到中间电池片,其中热处理的温度不低于树脂的分解温度；将中间电池片进行第二酸洗处理,以去除中间电池片表面的非晶硅薄膜,得到硅片；及对硅片进行制作光伏电池的步骤操作。如此保证了返工后的电池片的电池效率,实现了光伏电池印刷不良片的有效返工,避免了树脂在后续浸泡处理时残留在电池片上导致无法达到返工效果的问题,有效地减小由印刷不良而带来的经济损失,提高了经济效益。(The invention relates to a recovery method and a rework method of a photovoltaic cell piece with poor printing, which comprises the following steps: respectively carrying out heat treatment and first acid washing treatment on the poor printed sheet of the photovoltaic cell to remove the resin, the electrode and the transparent conductive oxide film on the surface of the poor printed sheet of the photovoltaic cell to obtain an intermediate cell sheet, wherein the temperature of the heat treatment is not lower than the decomposition temperature of the resin; carrying out second acid washing treatment on the intermediate cell to remove the amorphous silicon film on the surface of the intermediate cell to obtain a silicon wafer; and carrying out the step operation of manufacturing the photovoltaic cell on the silicon wafer. Therefore, the battery efficiency of the reworked battery piece is ensured, the effective reworking of the poor printed piece of the photovoltaic battery is realized, the problem that the reworking effect cannot be achieved due to the fact that resin is remained on the battery piece during subsequent soaking treatment is avoided, the economic loss caused by poor printing is effectively reduced, and the economic benefit is improved.)

1. A recovery method of a photovoltaic cell poor printing sheet is characterized by comprising the following steps:

respectively carrying out heat treatment and first acid washing treatment on the poor printed sheet of the photovoltaic cell to remove the resin, the electrode and the transparent conductive oxide film on the surface of the poor printed sheet of the photovoltaic cell to obtain an intermediate cell sheet, wherein the temperature of the heat treatment is not lower than the decomposition temperature of the resin; and

and carrying out second acid washing treatment on the intermediate battery piece to remove the amorphous silicon film on the surface of the intermediate battery piece.

2. A recycling method according to claim 1, characterized in that the conditions of the heat treatment are: sintering at 400-900 ℃ for 1-20 min in an oxygen-containing atmosphere.

3. The recovery method according to claim 1, wherein the acid solution used in the first acid washing treatment contains hydrochloric acid; in the acid solution adopted in the first acid washing treatment, the concentration of the hydrochloric acid is 5-37 wt%;

the temperature of the first acid washing treatment is 20-60 ℃, and the time is 5-120 min.

4. The recovery method according to claim 1, wherein the acid solution used in the second acid washing treatment comprises hydrofluoric acid and an oxidizing agent;

in the acid solution adopted in the second acid washing treatment, the concentration of the hydrofluoric acid is 0.5-10 wt%;

the temperature of the second acid washing treatment is 20-60 ℃, and the time is 2-20 min.

5. The recovery method of claim 4, wherein the oxidizing agent comprises at least one of ozone, nitric acid, and hydrogen peroxide.

6. The recovery method according to claim 5, wherein the oxidizing agent contains ozone, and the concentration of the ozone is 10ppm to 100 ppm; or

The oxidant contains nitric acid, and the concentration of the nitric acid is not higher than 20 wt%; or

The oxidant contains hydrogen peroxide, and the concentration of the hydrogen peroxide is not higher than 30 wt%.

7. The recovery process of any one of claims 1 to 6, further comprising, prior to the second acid wash treatment, the steps of:

carrying out third acid washing treatment on the battery piece after the first acid washing treatment; and the acid solution adopted by the third acid cleaning treatment is a solution containing nitric acid with the concentration of not less than 40 wt%.

8. The recycling method according to claim 7, wherein the step of heat-treating is prior to the step of first acid-washing treatment; or

The step of heat treatment is located between the steps of the first pickling treatment and the third pickling treatment; or

The step of heat treating is located between the steps of the third acid washing treatment and the second acid washing treatment.

9. The recovery method according to claim 7, wherein the temperature of the third acid washing treatment is 20 to 60 ℃ and the time is 5 to 120 min.

10. A reworking method for a poor printed sheet of a photovoltaic cell is characterized by comprising the following steps:

using the recovery method according to any one of claims 1 to 9, a silicon wafer is obtained; and

and carrying out the step operation of manufacturing the photovoltaic cell on the silicon wafer.

11. The rework method of claim 10, wherein the step of subjecting the silicon wafer to photovoltaic cell fabrication operations comprises the steps of:

and sequentially performing texturing, amorphous silicon film deposition, transparent conductive oxide film deposition, electrode printing and curing on the surface of the silicon wafer.

12. The rework method of claim 11, wherein the step of subjecting the silicon wafer to photovoltaic cell fabrication further comprises the steps of:

after the steps of printing electrodes and curing, the cell pieces are subjected to a light injection process.

13. The rework method of any one of claims 10 to 12, wherein the poorly printed sheet of photovoltaic cells is a sheet of cells printed with electrode paste uncured or a sheet of cells printed with electrode paste and cured.

Technical Field

The invention relates to the technical field of batteries, in particular to a recovery method and a rework method of a photovoltaic battery piece with poor printing.

Background

The solar photovoltaic cell (photovoltaic cell for short) is used for directly converting solar energy into electric energy. Silicon solar cells with silicon as a substrate are widely used in the ground photovoltaic system at present and can be divided into monocrystalline silicon, polycrystalline silicon and amorphous silicon solar cells.

Silicon Heterojunction Solar cells (SHJ cells for short in english) are a new generation of Silicon-based Solar cells following perc (passivated Emitter and reader cells) Solar cells. The SHJ battery has the advantages of simple production process, high battery conversion efficiency, good weak light effect, no light attenuation and the like, and is considered as the next generation of mass production solar battery technology in the industry. The manufacturing process of the SHJ battery mainly comprises four process steps of cleaning and texturing, amorphous silicon film (a-Si) deposition, transparent conductive oxide film (TCO) deposition and metallized electrode manufacturing. The metallized electrode is mainly manufactured by two methods, namely screen printing and electroplating, and the screen printing method is still mainly used at present.

In the printing process of preparing the SHJ battery, the factors such as equipment failure, unstable process, improper operation of personnel and the like easily cause a plurality of poor printed battery pieces, and the yield of the product is greatly influenced. The statistical data of production shows that the bad battery plates generally account for about 1.0-2.0%. The metallized electrode of the SHJ battery is mainly manufactured by adopting low-temperature silver paste and performing a screen printing mode of low-temperature curing, and the traditional reworking method cannot be applied; therefore, the current method for treating the battery piece is to degrade or scrap the battery piece according to fragments, which causes great economic loss.

Disclosure of Invention

Accordingly, there is a need for a method for recovering a defective printed sheet of a photovoltaic cell and a method for reworking the same, which can effectively reduce economic loss due to defective printing and improve economic efficiency.

The invention is realized by the following technical scheme.

In one aspect of the invention, a method for recovering a poor printed sheet of a photovoltaic cell is provided, which comprises the following steps:

respectively carrying out heat treatment and first acid washing treatment on the poor printed sheet of the photovoltaic cell to remove the resin, the electrode and the transparent conductive oxide film on the surface of the poor printed sheet of the photovoltaic cell to obtain an intermediate cell sheet, wherein the temperature of the heat treatment is not lower than the decomposition temperature of the resin; and

and carrying out second acid washing treatment on the intermediate battery piece to remove the amorphous silicon film on the surface of the intermediate battery piece.

In some of these embodiments, the conditions of the heat treatment are: sintering at 400-900 ℃ for 1-20 min in an oxygen-containing atmosphere.

In some of these embodiments, the acid solution used in the first acid washing treatment comprises hydrochloric acid; in the acid solution adopted in the first acid washing treatment, the concentration of the hydrochloric acid is 5-37 wt%;

the temperature of the first acid washing treatment is 20-60 ℃, and the time is 5-120 min.

In some embodiments, the acid solution used in the second acid washing process comprises hydrofluoric acid and an oxidizing agent;

in the acid solution adopted in the second acid washing treatment, the concentration of the hydrofluoric acid is 0.5-10 wt%;

the temperature of the second acid washing treatment is 20-60 ℃, and the time is 2-20 min.

In some of these embodiments, the oxidizing agent comprises at least one of ozone, nitric acid, and hydrogen peroxide.

In some embodiments, the oxidizing agent comprises ozone, and the concentration of the ozone is 10ppm to 100 ppm; or

The oxidant contains nitric acid, and the concentration of the nitric acid is not higher than 20 wt%; or

The oxidant contains hydrogen peroxide, and the concentration of the hydrogen peroxide is not higher than 30 wt%.

In some of these embodiments, prior to the second pickling treatment, the recovery process further comprises the steps of:

carrying out third acid washing treatment on the battery piece after the first acid washing treatment; and the acid solution adopted by the third acid cleaning treatment is a solution containing nitric acid with the concentration of not less than 40 wt%.

In some of these embodiments, the step of heat treating precedes the step of first acid washing; or

The step of heat treatment is located between the steps of the first pickling treatment and the third pickling treatment; or

The step of heat treating is located between the steps of the third acid washing treatment and the second acid washing treatment.

In some embodiments, the temperature of the third acid washing treatment is 20-60 ℃ and the time is 5-120 min.

In another aspect of the invention, a rework method of a poor printed sheet of a photovoltaic cell is provided, which comprises the following steps:

obtaining a silicon wafer by adopting any one of the recovery methods; and

and carrying out the step operation of manufacturing the photovoltaic cell on the silicon wafer.

In some of these embodiments, the step of subjecting the silicon wafer to photovoltaic cell fabrication comprises the steps of:

and sequentially performing texturing, amorphous silicon film deposition, transparent conductive oxide film deposition, electrode printing and curing on the surface of the silicon wafer.

In some of these embodiments, the step of operating the silicon wafer to fabricate a photovoltaic cell further comprises the steps of:

after the steps of printing electrodes and curing, the cell pieces are subjected to a light injection process.

In some of these embodiments, the photovoltaic cell poor printed sheet is a printed electrode paste uncured sheet or a printed electrode paste and cured sheet.

According to the recovery method and the rework method of the photovoltaic cell poor printing sheet, the resin, the electrode and the transparent conductive oxide film on the surface of the photovoltaic cell poor printing sheet can be removed through heat treatment and first acid washing treatment, and the temperature of the heat treatment is not lower than the decomposition temperature of the resin; the amorphous silicon film on the surface of the middle cell piece is further removed by adopting second acid washing treatment, so that the step operation of manufacturing the photovoltaic cell again by taking the obtained silicon wafer as a basic silicon wafer is carried out, the cell efficiency of the reworked cell piece is ensured, the effective reworking of the printed defective piece of the photovoltaic cell is realized, the problem that the reworking effect cannot be achieved due to the fact that resin is remained on the cell piece during subsequent soaking treatment is avoided, the economic loss caused by poor printing is effectively reduced, the economic benefit is improved, and the integral yield of the product is favorably improved.

Drawings

FIG. 1 is an optical photograph of an SHJ cell piece obtained by the HCl soaking treatment of step (2) of example 1;

fig. 2 is an optical photograph of an SHJ cell sheet obtained by the HCl immersion treatment of step (1) of comparative example 1.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any order or number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

At present, for a poor battery piece generated in the manufacture of a PERC battery after screen printing, the reworking method generally comprises the following steps: soaking the battery piece in alcohol → wiping silver paste and aluminum paste with dust-free paper → pickling residual metal impurities → screen printing again. However, a person skilled in the art has found through extensive practice that the rework method is not suitable for poor cell pieces after screen printing generated in the manufacture of SHJ cells. The study finds that the following problems can be caused if the SHJ battery is completely reworked according to the rework process of the PERC battery: firstly, after the battery piece is soaked in alcohol, the battery piece is wiped by using dust-free paper, so that the whole silver paste can not be removed like a PERC battery, even if a part of the battery piece is removed, serious residual printing exists, and the product quality requirement can not be met; secondly, the main component of the blue film of the PERC battery is SiNx, and the main component of the blue film (namely TCO film) of the SHJ battery is indium oxide; the difference of the material properties of the two is great. The optical characteristics of the TCO film are poor after alcohol wiping and acid washing, and the TCO film cannot be used continuously.

The reason for this is analyzed by the skilled person, mainly due to the following differences between the SHJ cell and the PERC cell. First, the PN junction of a PERC cell is formed by high temperature phosphorus diffusion; the PN junction of the SHJ battery is composed of an amorphous silicon film, and the amorphous silicon film is not high in temperature resistance; second, based on the first point, in the screen printing for preparing the SHJ cell, the electrode paste used is a low-temperature silver paste composed of a resin, a silver paste, etc., and the electrode paste used in the screen printing for preparing the PERC cell is a high-temperature silver paste composed of a glass frit, a silver paste, etc. Further investigation by the skilled artisan has revealed that these residual marks are mainly due to marks left by resin spreading in the SHJ cell, which are difficult to remove by means of alcohol-soaked wiping. More seriously, if the residual resin, such as the resin on the electrode, is not removed in time, the residual resin will remain on the battery piece in the subsequent acid washing process, and finally the product quality requirement can not be met.

Based on this, an embodiment of the present invention provides a rework method of a defective printed sheet of a photovoltaic cell, including the following steps S1 to S3.

Step S1: and respectively carrying out heat treatment and first acid washing treatment on the poor printed sheet of the photovoltaic cell to remove the resin, the electrode and the transparent conductive oxide film on the surface of the poor printed sheet of the photovoltaic cell to obtain an intermediate cell sheet, wherein the temperature of the heat treatment is not lower than the decomposition temperature of the resin.

The poor printing sheet of the photovoltaic cell comprises the following components: various defective photovoltaic cell sheets generated in the step of printing to form electrodes for producing photovoltaic cells.

It is understood that the photovoltaic cell of the present invention includes, but is not limited to, SHJ cell and HBC cell, as long as the photovoltaic cell is a laminate cell comprising a transparent conductive oxide thin film, an amorphous silicon film, and an electrode made of silver paste containing resin, can be processed by the method of the present invention.

In some of the embodiments, the photovoltaic cell is an SHJ cell, which uses a silicon wafer as a substrate, and has an amorphous silicon thin film and a transparent conductive oxide film on both surfaces, i.e., the front surface and the back surface of the cell, in sequence from the substrate to the outer layer. Only the specific types of the amorphous silicon thin films on the front and back sides of the battery are different, and detailed description thereof is omitted.

Specifically, the poor printed sheet of the photovoltaic cell of the present invention includes, but is not limited to: printing the electrode paste uncured battery piece or printing the electrode paste and curing the battery piece. The battery piece without solidified printed electrode paste comprises a battery piece without dried printed electrode paste and a battery piece without solidified dried printed electrode paste.

It is worth mentioning that: the temperature of the heat treatment in step S1 is not lower than the decomposition temperature of the resin, so the heat treatment step can decompose the resin in the electrode paste under the heat treatment conditions. However, the sintering temperature of the heat treatment is high for the amorphous silicon thin film, which may damage the amorphous silicon thin film, and thus the amorphous silicon thin film needs to be reworked.

The primary purpose of the first acid washing treatment in step S1 is to dissolve the transparent conductive oxide thin film with an acid solution, and since the electrodes are formed on the transparent conductive oxide thin film, the electrodes on the upper surface of the battery piece are removed while the transparent conductive oxide thin film on the upper surface of the battery piece is dissolved and removed.

It is understood that the present invention does not limit the order of the heat treatment and the first acid washing treatment; in other words, the step of heat treatment may be before or after the step of first acid washing treatment.

Preferably, the step of heat treatment precedes the step of first acid washing treatment; thus, before each acid washing treatment, the resin is decomposed and removed, so that the influence of the existence of the resin on the battery efficiency is avoided; and even a small amount of residue can be effectively removed in the subsequent acid washing treatment, and the residue can not be remained on the battery piece.

In other examples, the step of heat treating may be after the step of first acid washing treatment. The resin can be prevented from remaining on the silicon wafer to be textured just before the second acid washing treatment in step S2, thereby ensuring the cell efficiency of the reworked cell.

It should be noted that, when the photovoltaic cell poor printing sheet of the present invention is a cell sheet with uncured printing electrode paste, before performing step S1, the method may further include: and removing the uncured electrode paste printed on the poor printed sheet of the photovoltaic cell by using an organic solvent such as ethanol.

Although the uncured electrode paste printed on the poor printed sheet of the photovoltaic cell is removed by the organic solvent, the resin print in the electrode paste remains on the transparent conductive oxide film. Therefore, the subsequent steps of heat treatment and first acid washing treatment are still required.

It is understood that, in some examples, the step of removing the printed uncured electrode paste on the poor printed sheet of the photovoltaic cell may be not performed, but the steps of the heat treatment and the first acid washing treatment of the direct step S1 may be performed.

Further, in the present invention, each step of the acid-washing treatment is preferably performed by acid-soaking. After each pickling treatment, the metal strip can be taken out by washing with water.

In some of these embodiments, the conditions of the heat treatment are: sintering at 400-900 ℃ for 1-20 min in an oxygen-containing atmosphere. Thus, it is preferable to sinter the electrode in an oxygen-containing atmosphere at the above-mentioned specific heat treatment temperature for a specific time to effectively remove the resin in the electrode on the surface of the poorly printed sheet of the photovoltaic cell.

Further, the conditions of the heat treatment are: sintering at 500-900 deg.c for 2-10 min in oxygen-containing atmosphere.

Further, the oxygen-containing atmosphere may be an air atmosphere.

Step S2: and carrying out second acid washing treatment on the intermediate cell to remove the amorphous silicon film on the surface of the intermediate cell to obtain the silicon wafer.

As described above, the amorphous silicon thin film is damaged in the step of heat treatment, and thus the amorphous silicon thin film needs to be removed in step S2 in order to be reworked.

Therefore, the invention also provides a method for recovering the poor printing sheet of the photovoltaic cell, which comprises the steps of S1 and S2, and the silicon sheet is obtained by recovery. Further, the recovery method may further include step S4 mentioned later.

It is understood that the silicon wafer recovered by the present invention can be reworked to manufacture a photovoltaic cell by the step S3 mentioned later, and can be used for other purposes, which is not limited herein.

Step S3: and (3) manufacturing a photovoltaic cell on the surface of the silicon wafer.

It is understood that step S3 can be performed using conventional photovoltaic cell fabrication processes.

In some embodiments, the photovoltaic cell is an SHJ cell, and step S3 includes the steps of: the method comprises the steps of texturing, depositing an amorphous silicon film, depositing a transparent conductive oxide film, printing an electrode and curing the surface of a silicon wafer in sequence.

It can be understood that after texturing, an amorphous silicon film is deposited on the surface of the cell to prepare the PN junction.

Further, in a specific example, the step of depositing the amorphous silicon thin film on the surface of the cell slice comprises the steps of sequentially forming intrinsic amorphous silicon and an N-type doped amorphous silicon thin film on the front side of the cell slice; and sequentially forming a back intrinsic amorphous silicon film and a P-type doped amorphous silicon film on the back of the cell.

The transparent conductive oxide film deposited on the amorphous silicon film serves as a blue film. The purpose of depositing the transparent conductive oxide film is to passivate the surface of the amorphous silicon film and to increase the transmission of lateral current.

Further, the transparent conductive oxide thin film may be at least one of tin-doped indium oxide (ITO), tungsten-doped indium oxide (IWO), or other doped indium oxide.

Electrodes are formed on the transparent conductive oxide film for the purpose of printing and curing to conduct a current generated by light irradiation. Generally, the electrodes are in the shape of a grid.

Further, the curing condition after printing the electrode paste is that the electrode paste is processed for 10min to 40min at the temperature of 170 ℃ to 200 ℃. Further, the electrode paste includes a resin and a silver paste.

In some of these embodiments, step S3 further includes the steps of: and carrying out light injection treatment on the cell piece after electrode printing and curing so as to repair defects in the photovoltaic cell and improve the cell conversion efficiency.

Further, the light injection treatment is a front side light injection treatment on the cell slice.

According to the reworking method of the poor printed sheet of the photovoltaic cell, the resin, the electrode and the transparent conductive oxide film on the surface of the poor printed sheet of the photovoltaic cell can be removed through heat treatment and first acid pickling treatment, and the temperature of the heat treatment is not lower than the decomposition temperature of the resin; the amorphous silicon film on the surface of the middle cell piece is further removed by adopting second acid washing treatment, so that the step operation of manufacturing the photovoltaic cell again by taking the obtained silicon wafer as a basic silicon wafer is carried out, the cell efficiency of the reworked cell piece is ensured, the effective reworking of the printed defective piece of the photovoltaic cell is realized, the problem that the reworking effect cannot be achieved due to the fact that resin is remained on the cell piece during subsequent soaking treatment is avoided, the economic loss caused by poor printing is effectively reduced, the economic benefit is improved, and the integral yield of the product is favorably improved.

In some of these embodiments, the rework method further includes, before the second pickling process, the following step S4:

carrying out third acid washing treatment on the battery piece after the first acid washing treatment; the acid solution used in the third acid washing treatment is a solution containing nitric acid with a concentration of not less than 40 wt%.

The third acid washing treatment is used for cleaning the battery piece and comprises the following steps: and residual metal impurities on the surface of the cell are further cleaned, so that the influence on the performance of the reworked cell is avoided.

When the step of heat treatment is located after the first pickling treatment, the step of heat treatment may be located between the steps of the first pickling treatment and the third pickling treatment, or may be located between the steps of the third pickling treatment and the second pickling treatment.

Further, the acid solution adopted by the third acid washing treatment is a nitric acid solution or aqua regia with the concentration of 40-98 wt%. Furthermore, the acid solution used in the third acid washing treatment is a nitric acid solution with a concentration of 60 wt% to 98 wt%.

Further, the temperature of the third acid washing treatment is 20-60 ℃, and the time is 5-120 min. Further, the temperature of the third acid washing treatment is 20 to 30 ℃. Furthermore, the time of the third acid cleaning treatment is 5min to 30 min.

In some of these embodiments, the acid used in the first acid wash treatment comprises hydrochloric acid. Further, in the acid solution adopted in the first acid washing treatment, the concentration of the hydrochloric acid solution is 5-37 wt%; furthermore, the concentration of the hydrochloric acid solution is 20 wt% to 37 wt%. In one embodiment, the acid solution used in the first acid washing process is hydrochloric acid.

Further, the temperature of the first acid washing treatment is 20-60 ℃, and the time is 5-120 min. Further, the temperature of the first acid washing treatment is 20 to 30 ℃. Furthermore, the time of the first acid washing treatment is 5min to 30 min.

In some embodiments, the acid solution used in the second acid washing process contains hydrofluoric acid and an oxidizing agent to clean the amorphous silicon thin film on the surface of the cell.

Further, in the acid solution adopted in the second acid washing treatment, the concentration of hydrofluoric acid is 0.5 wt% -10 wt%; furthermore, the concentration of the hydrofluoric acid is 2 wt% -8 wt%.

Further, the temperature of the second acid washing treatment is 20-60 ℃, and the time is 2-20 min. Further, the temperature of the second acid washing treatment is 20 ℃ to 30 ℃. Furthermore, the time of the second acid washing treatment is 2min to 10 min.

Further, the oxidizing agent includes at least one of ozone, nitric acid, and hydrogen peroxide.

Furthermore, the oxidant contains ozone, and the concentration of the ozone is 10ppm to 100 ppm.

Further, the oxidizing agent contains nitric acid, and the concentration of the nitric acid is not higher than 20 wt%.

Further, the oxidizing agent contains hydrogen peroxide, and the concentration of the hydrogen peroxide is not higher than 30 wt%.

In order to make the objects, technical solutions and advantages of the present invention more concise and clear, the present invention is described with the following specific embodiments, but the present invention is by no means limited to these embodiments. The following described examples are only preferred embodiments of the present invention, which can be used to describe the present invention and should not be construed as limiting the scope of the present invention. It should be understood that any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

In order to better illustrate the invention, the following examples are given to further illustrate the invention. The following are specific examples.

It should be noted that: in each embodiment, the electrode paste for the defective printed sheet and the rework printing is made of the same material, and the components of the electrode paste comprise resin and silver paste. In a specific embodiment, the slurry used for the main grid is DD-1760R-103, the slurry used for the fine grid is DD-1760Q-116, and the manufacturer is KYOTO ELEX. The objects to which the present invention is applied are not limited to the above two types.

Example 1

The SHJ cell poor-printing sheet of example 1 was a cell produced in the screen printing step and printed with an electrode paste and cured.

(1) And (3) heat treatment: placing the poor battery piece generated in the screen printing process into a high-temperature furnace (air atmosphere, the same below) at 500 ℃ for heat treatment for 5min, decomposing resin left after curing when printing a metal electrode at the moment in high temperature, and immediately taking out the battery piece from the high-temperature furnace and placing the battery piece in a wet flower basket;

(2) and (3) HCl soaking treatment: soaking the SHJ battery piece obtained in the step (1) in a tank filled with HCl solution with the mass fraction of 37% for 5min at 25 ℃, dissolving the TCO film by HCl at the moment, and taking out the battery piece from the tank, wherein the corresponding front/back metal electrodes fall off along with the TCO film;

(3)HNO₃soaking treatment: soaking the SHJ battery piece obtained in the step (2) in a tank containing a concentrated nitric acid solution with the mass fraction of 98% for 5min at 25 ℃, dissolving a small amount of metal impurities remained on the surface of the battery piece by the nitric acid, and taking out the battery piece from the tank;

(4) HF soaking treatment: putting the SHJ battery piece obtained in the step (3) into a container containing HF with the mass fraction of 5% and O with the concentration of 30ppm₃Treating the mixed solution in a tank body at 25 ℃ for 5min, removing the amorphous silicon film on the front and back surfaces of the SHJ battery by using an HF solution containing ozone, and taking out the battery piece from the tank body;

the steps (2), (3) and (4) are wet treatment containing chemical reagents, so that the surface of the cell piece is cleaned by soaking with ultrapure water after each step of chemical treatment. It can be understood that the subsequent steps (5) - (9) are performed according to the conventional process of the SHJ battery piece.

(5) Texturing and cleaning: performing secondary surface texturing and surface cleaning treatment on the battery piece (namely the silicon chip) obtained in the step (4), wherein the texturing weight is controlled to be about 0.3 g;

(6) amorphous silicon thin film deposition: performing front intrinsic amorphous silicon and N-type doped amorphous silicon film deposition and back intrinsic amorphous silicon and P-type doped amorphous silicon film deposition on the textured silicon wafer obtained in the step (5) so as to passivate the surface of the crystalline silicon and form a PN junction;

(7) TCO film deposition: depositing a positive TCO film on the back surface of the cell piece with the amorphous silicon film deposited on the surface in the step (6) so as to passivate the surface of the amorphous silicon and increase the transmission of transverse current;

(8) manufacturing a metal electrode: and (4) printing and curing the metal electrodes on the front side and the back side of the battery piece obtained in the step (7) so as to lead out current generated by illumination. Wherein the curing condition is 180 ℃ for 30 min.

(9) Light injection treatment: and (4) performing front side illumination treatment on the cell obtained in the step (8) to repair defects in the SHJ cell and improve the cell conversion efficiency. And manufacturing the reworked SHJ battery.

Example 2

The SHJ cell poor-printing sheet of example 2 was a cell produced in the screen printing process and printed with an electrode paste and cured.

(1) And (3) HCl soaking treatment: soaking the poor battery piece produced in the screen printing process in a tank filled with HCl solution with the mass fraction of 20% for 30min at 25 ℃, dissolving the TCO film by HCl at the moment, and taking out the battery piece from the tank along with the falling of the corresponding front/back metal electrodes;

(2) and (3) heat treatment: putting the SHJ battery piece obtained in the step (1) into a high-temperature furnace with the temperature of 700 ℃ for heat treatment for 2min, decomposing resin left after curing when printing a metal electrode at the moment in high temperature, and immediately taking out the battery piece from the high-temperature furnace and placing the battery piece in a wet-process flower basket;

(3)HNO₃soaking treatment: soaking the SHJ battery piece obtained in the step (2) in a tank containing 60% concentrated nitric acid solution at 25 ℃ for 30min,at the moment, a small amount of metal impurities remained on the surface of the cell are dissolved by nitric acid, and then the cell is taken out from the groove body;

(4) HF soaking treatment: putting the SHJ battery piece obtained in the step (3) into a container containing 5% by mass of HF and 5% by mass of HNO₃Treating the mixed solution in a tank body at 25 ℃ for 5min, removing the amorphous silicon film on the front and back surfaces of the SHJ battery by using an HF solution containing nitric acid, and taking out the battery piece from the tank body;

all the steps (1), (3) and (4) are wet treatment containing chemical reagents, so that the surface of the cell piece is cleaned by soaking with ultrapure water after each step of chemical treatment.

The subsequent steps (5) to (9) are the same as in example 1.

Example 3

The SHJ cell poor-printing sheet of example 3 was a cell produced in the screen printing process and printed with an electrode paste and cured. Example 3 is substantially the same as example 1 except that the order of the steps of the heat treatment is different.

(1) And (3) HCl soaking treatment: placing the poor battery piece produced in the screen printing process into a tank containing 37% of HCl solution by mass percent, soaking for 5min at 25 ℃, dissolving the TCO film by HCl at the moment, and taking out the battery piece from the tank, wherein the corresponding front/back metal electrodes fall off along with the TCO film;

(2)HNO₃soaking treatment: soaking the SHJ battery piece obtained in the step (1) in a tank containing a concentrated nitric acid solution with the mass fraction of 98% for 5min at 25 ℃, dissolving a small amount of metal impurities remained on the surface of the battery piece by the nitric acid, and taking out the battery piece from the tank;

(3) and (3) heat treatment: putting the SHJ battery piece obtained in the step (2) into a high-temperature furnace (air atmosphere, the same below) at the temperature of 500 ℃ for heat treatment for 5min, decomposing resin left after curing when printing a metal electrode at the moment at high temperature, and immediately taking out the battery piece from the high-temperature furnace and placing the battery piece in a wet-process basket;

(4) HF soaking treatment: putting the SHJ battery piece obtained in the step (3) into a container containing HF with the mass fraction of 5% and O with the concentration of 30ppm₃The tank of the mixed solution of (1)Treating at 25 deg.C for 5min, removing the amorphous silicon film on the front and back surfaces of SHJ battery with HF solution containing ozone, and taking out the battery piece from the tank;

the steps (1), (2) and (4) are wet treatment containing chemical reagents, so that the surface of the cell piece is cleaned by soaking with ultrapure water after each step of chemical treatment.

The subsequent steps (5) to (9) are the same as in example 1.

And manufacturing the reworked SHJ battery.

Example 4

Example 4 is essentially the same as example 1, except that: the sintering temperature of the heat treatment is 400 ℃ and the time is 20 min.

Example 5

Example 5 is essentially the same as example 1, except that: the sintering temperature of the heat treatment is 900 ℃ and the time is 10 min.

Comparative example 1

Comparative example 1 is essentially the same as example 1 except that: comparative example 1 the heat treatment step of step (1) in example 1 was not performed, but the process conditions of step (2) and other steps were the same by directly placing the defective cell in the cell body. Specifically, steps (1) to (3) of comparative example 1 are as follows:

(1) and (3) HCl soaking treatment: placing the poor battery piece produced in the screen printing process into a tank containing 37% of HCl solution by mass percent, soaking for 5min at 25 ℃, dissolving the TCO film by HCl at the moment, and taking out the battery piece from the tank, wherein the corresponding front/back metal electrodes fall off along with the TCO film;

(2)HNO₃soaking treatment: soaking the SHJ battery piece obtained in the step (1) in a tank containing a concentrated nitric acid solution with the mass fraction of 98% for 5min at 25 ℃, dissolving a small amount of metal impurities remained on the surface of the battery piece by the nitric acid, and taking out the battery piece from the tank;

(3) HF soaking treatment: putting the SHJ battery piece obtained in the step (2) into a container containing HF with the mass fraction of 5% and O with the concentration of 30ppm₃The mixed solution is treated in a tank body at 25 ℃ for 5min, and at the moment, the amorphous silicon on the front and back surfaces of the SHJ batteryRemoving the film by HF solution containing ozone, and taking out the cell from the tank body;

the steps (1), (2) and (3) are wet treatment containing chemical reagents, so that the surface of the cell piece is cleaned by soaking with ultrapure water after each step of chemical treatment.

Comparative example 2

Comparative example 2 is substantially the same as example 1 except that the temperature of the heat treatment of step (1) in comparative example 2 is 300 ℃ for 10 min.

The SHJ cells obtained by the HCl immersion treatment of example 1 and comparative example 1 were optically inspected to obtain optical photographs of fig. 1 and 2, respectively. In fig. 1 and 2, (a) is an overall optical photograph of an SHJ cell obtained by an HCl immersion process; (b) is a partial magnified photo of the exemplary area of the circle on the corresponding (a).

It is clear from this that example 1 effectively removed the resin by the high temperature heat treatment. The cell of comparative example 1, which was directly subjected to the HCl immersion treatment without high-temperature heat treatment, appeared clean in macroscopical view, however, in practice, after the gate line electrode and the TCO film were removed, a large amount of extended resin marks still existed on the surface of the cell in the gate line electrode region, and such resin marks seriously affected the appearance and electrical properties of the cell in subsequent rework.

The following are the I/V electrical property tests performed on the SHJ battery pieces prepared in the respective examples and comparative examples, and the results of the property tests are shown in the following tables.

The normal process refers to the conventional process for manufacturing the SHJ cell in the steps (5) to (9) of the example 1 to manufacture the qualified cell. The number of the investigation of each example is 400, and each performance result is an average value of 400 battery pieces.

Where Eta is the cell efficiency (%), Voc is the open circuit voltage (V), Isc is the short circuit current (a), and FF is the fill factor (%).

The test conditions were: AM1.5 Spectrum (i.e. 1.0 KW/m)²) At 25 ℃. The tester is a Halm tester.

Group of	Quantity (pcs)	Eta(％)	Voc(V)	Isc(A)	FF(％)
						Example 1	400	23.85	0.7431	9.344	83.92
Example 2	400	23.82	0.7432	9.325	83.99
						Example 3	400	23.84	0.7435	9.328	83.97
Example 4	400	23.83	0.7435	9.327	83.96
						Example 5	400	23.84	0.7428	9.345	83.92
Comparative example 2	400	23.35	0.7410	9.283	82.95
						Normal process	400	23.86	0.7435	9.324	84.08

As can be seen from the above table, the performances of the SHJ battery pieces obtained after the reworking in examples 1 to 5 are equivalent to those of the SHJ battery pieces obtained by the normal process, and the reworking method is feasible and can improve the economic benefit.

Compared with the SHJ battery piece prepared by a normal process, the SHJ battery piece prepared by the comparative example 2 has the performance aspects of open-circuit voltage, short-circuit current, filling factor and the like which are reduced to different degrees, and the battery efficiency is further reduced by 0.5%; does not meet the production requirement.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims, and the description and the drawings can be used for explaining the contents of the claims.