Processing method of heterojunction battery

Abstract

The invention relates to the technical field of solar cells, in particular to a processing method of a heterojunction cell, comprising: providing a heterojunction cell and a cell box, the heterojunction cell at least comprising a semiconductor substrate layer, a semiconductor functional layer and a transparent conductive layer which are stacked; the battery box is suitable for placing a heterojunction battery; providing a sealing bag; placing the heterojunction battery in a battery box; after the heterojunction battery is placed in a battery box, the battery box is placed in a sealing bag; the sealing bag is vacuumized so that the sealing bag can be tightly attached to the battery box; and after the sealing bag is vacuumized, the sealing bag is placed in a low-temperature environment to be stored. The method further comprises the step of performing recovery treatment on the heterojunction cell after being stored in a low-temperature environment and before being taken out for use. Comprising electric injection processing and / or light injection processing. The processing method of the heterojunction battery provided by the invention can inhibit dark attenuation of the heterojunction battery.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a processing method for a heterojunction cell. Background Art

[0002] Heterojunction cells have the advantages of high conversion efficiency, simple manufacturing process, thin silicon wafer application, low temperature coefficient, no photo-induced degradation and potential degradation, and double-sided power generation. The advantages of heterojunction cell modules in conversion efficiency greatly exceed those of other types of cells (such as PERC and TOPCon), and the average conversion efficiency is expected to exceed 25%. However, in actual production, the produced heterojunction cells often cannot be made into heterojunction cell modules in the first time, and require a long storage time; or when heterojunction cells are sent for sample testing, they also require a long storage time due to logistics. After being stored for a certain period of time, the efficiency of heterojunction cells will have a certain degree of dark decay, that is, after the production of heterojunction cells is completed, the photoelectric conversion efficiency of heterojunction cells will decay when they are packaged and sealed without strong light exposure. Correspondingly, other types of solar cells, such as PERC and TOPCon cells, generally do not experience obvious photoelectric conversion efficiency decay during light-proof storage.

[0003] In order to suppress the dark decay of heterojunction cells, the current practice is to place heterojunction cells in a nitrogen environment. However, placing heterojunction cells in a nitrogen environment requires nitrogen to be passed into a nitrogen cabinet specifically for storing heterojunction cells, and professionals are required to regularly check the air tightness of the pipeline, which has high maintenance costs. In addition, the above solution is not ideal for suppressing the dark decay of heterojunction cells. After testing, the above solution will still reduce the conversion efficiency by 0.12% due to dark decay on the 21st day of storage.

[0004] Therefore, there is an urgent need for a better way to properly store or handle heterojunction cells to suppress the dark decay of heterojunction cells. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is how to better suppress the dark decay of heterojunction batteries, thereby providing a processing method for heterojunction batteries.

[0006] The present invention provides a method for processing a heterojunction battery, comprising: the heterojunction battery at least comprises a semiconductor substrate layer, a semiconductor functional layer and a transparent conductive layer which are stacked; the method comprises: providing a sealing bag; placing the heterojunction battery in a battery box; after placing the heterojunction battery in the battery box, placing the battery box in the sealing bag; performing a vacuum treatment on the sealing bag so that the sealing bag is tightly attached to the battery box; after performing the vacuum treatment on the sealing bag, placing the sealing bag in a low-temperature environment for storage; the temperature of the low-temperature environment is -20°C to -10°C; and further comprising, after being stored in the low-temperature environment and before being taken out for use, performing a recovery treatment on the heterojunction battery; the recovery treatment comprises: an electrical injection treatment and / or a light injection treatment.

[0007] Optionally, the suction force of the vacuum treatment is 50 kPa to 80 kPa, and the time of the vacuum treatment is 5 s to 8 s.

[0008] Optionally, before vacuuming the sealed bag, the method further comprises: placing a desiccant in the sealed bag; the desiccant comprises anhydrous calcium chloride.

[0009] Optionally, the humidity of the low-temperature environment is 60% to 75%; during the process of storing the sealed bag in the low-temperature environment, the method further includes: introducing a protective atmosphere into the low-temperature environment; the protective atmosphere includes at least one of nitrogen, helium or argon.

[0010] Optionally, the step of placing the heterojunction battery in the battery box includes: providing a plurality of heterojunction batteries and stacking the plurality of heterojunction batteries; during the stacking process, setting a spacer layer between adjacent heterojunction batteries, setting a buffer layer on the surface of the outermost heterojunction battery, and after setting the buffer layer, setting a support layer on the side of the buffer layer away from the heterojunction battery; after stacking and setting the spacer layer, the buffer layer and the support layer, placing the stacked heterojunction batteries in the battery box; wherein: the spacer layer includes sulfuric acid paper; the buffer layer includes a foam board; the support layer includes a hard plastic board, and the Shore hardness of the hard plastic board is 80HD~90HD.

[0011] Optionally, the method further includes: before performing the recovery treatment, taking out the heterojunction battery in the sealed bag placed in the low-temperature environment and performing a static treatment; the static treatment time is 8 minutes to 15 minutes.

[0012] Optionally, the step of performing electrical injection treatment on the heterojunction battery includes: preheating the heterojunction battery; contacting the surface of the heterojunction battery with an electrode for electrical injection treatment; during the electrical injection treatment, using a blower to ventilate the heterojunction battery; the current of the electrical injection treatment is 6A to 10A, the time is 10min to 15min, and the temperature is 60℃ to 80℃.

[0013] Optionally, the step of performing light injection treatment on the heterojunction battery includes: preheating the heterojunction battery; performing light treatment on the heterojunction battery; during the light treatment, using a blower to purge the heterojunction battery; the light intensity of the light treatment is 70kW / m2~90kW / m2, the temperature is 180℃~190℃, and the time is 2min~4min; the light treatment uses one of halogen light, red light or infrared light.

[0014] Optionally, the method further includes: forming a gate electrode on a side of the transparent conductive layer away from the semiconductor substrate layer before placing the heterojunction battery in the battery box, or, after taking out the heterojunction battery from a sealed bag placed in a low-temperature environment for static treatment and before performing a recovery treatment on the heterojunction battery, forming a gate electrode on a side of the transparent conductive layer away from the semiconductor substrate layer.

[0015] Optionally, the method also includes: in the process of forming a gate line electrode on a side of the transparent conductive layer away from the semiconductor substrate layer, first forming an uncured gate line electrode, and then curing the gate line electrode to form a cured gate line electrode; the curing treatment temperature is 120°C to 140°C, and the time is 5min to 10min.

[0016] The beneficial effects of the present invention are:

[0017] The processing method of the heterojunction battery provided by the present invention first performs a vacuum treatment on the sealing bag to remove the water vapor in the battery box due to exposure to the atmospheric environment. During the vacuum treatment, the vacuum is performed by controlling the suction force so that the sealing bag is close to the battery box, thereby avoiding damage to the heterojunction battery; after the sealing bag is vacuumed, the sealing bag is placed in a low-temperature environment for storage. Specifically, a device with a refrigeration function can be selected, such as a refrigerator or a freezer. This can save complex factory service requirements and reduce maintenance costs; secondly, storage in a low-temperature environment can suppress the reduction of the life of minority carriers in the heterojunction battery, thereby suppressing the dark decay of the heterojunction battery. After testing, on the 21st day, the conversion efficiency did not decrease significantly, effectively avoiding the power loss of the battery cell due to dark decay during storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 Flow chart of a method for processing a heterojunction battery in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] This embodiment provides a method for processing a heterojunction battery, comprising: providing a heterojunction battery and a battery box, wherein the heterojunction battery at least comprises a semiconductor substrate layer, a semiconductor functional layer and a transparent conductive layer arranged in layers; and the battery box is suitable for placing the heterojunction battery;

[0023] refer to Figure 1 , also includes:

[0024] S1: Provide sealed bag;

[0025] S2: placing the heterojunction battery in a battery box;

[0026] S3: After placing the heterojunction battery in the battery box, placing the battery box in the sealed bag;

[0027] S4: vacuuming the sealing bag so that the sealing bag fits tightly against the battery box;

[0028] S5: After the sealed bag is vacuumed, the sealed bag is placed in a low temperature environment for storage;

[0029] Wherein, the temperature of the low temperature environment is -20°C to -10°C.

[0030] The invention also includes: S6: performing a recovery process on the heterojunction battery before taking it out for use after being stored in a low-temperature environment; the recovery process includes:

[0031] Electrical injection processing and / or optical injection processing.

[0032] In this embodiment, the sealing bag is first vacuumed to remove the water vapor in the battery box due to the heterojunction battery exposed to the atmosphere. During the vacuuming process, the vacuum is performed by controlling the suction force so that the sealing bag is close to the battery box, which can avoid damage to the heterojunction battery. After the sealing bag is vacuumed, the sealing bag is placed in a low-temperature environment for storage. Specifically, a device with a refrigeration function can be selected, such as a refrigerator or freezer. This can save complex factory service requirements and reduce maintenance costs. Secondly, storage in a low-temperature environment can inhibit the reduction of the life of minority carriers in the heterojunction battery, thereby inhibiting the dark decay of the heterojunction battery. In addition, although low-temperature storage can greatly inhibit dark decay, there will always be a certain degree of dark decay in the heterojunction battery. In order to restore the dark decay caused during the storage process, the heterojunction battery needs to be restored to a certain extent, which can further improve the passivation effect of the semiconductor functional layer, reduce carrier recombination, and improve the effective doping rate.

[0033] In this embodiment, the material of the semiconductor substrate layer includes a silicon wafer, which is usually an N-type silicon wafer for heterojunction cells; the semiconductor functional layer includes an intrinsic semiconductor layer on opposite sides of the semiconductor substrate layer and a doped semiconductor layer on the side of the intrinsic semiconductor layer facing away from the semiconductor substrate layer, wherein the intrinsic semiconductor layer includes an amorphous silicon layer, which is usually used to passivate the N-type silicon wafer; the doped semiconductor layer includes an amorphous silicon layer, a single-sided microcrystalline silicon layer or a double-sided microcrystalline silicon layer; the conductivity type of the doped semiconductor layer located on both sides of the semiconductor substrate layer includes P-type or N-type, and forms a PN junction or a high-low junction with the N-type silicon wafer, respectively, and the carriers excited by sunlight move in a certain direction to form a pressure difference. In other embodiments, the material of the semiconductor substrate layer is a single crystal or a silicon germanium wafer.

[0034] It should be understood that the attenuation of heterojunction cells that is not produced under particularly strong light conditions can be called dark attenuation. In terms of heterojunction, dark attenuation is an abnormal SW effect, in which defects will be generated inside the heterojunction cell after a long period of strong light irradiation or current passing through it, causing the performance of the transparent conductive layer in the heterojunction cell to deteriorate.

[0035] Specifically, the suction force of the vacuum treatment is 50 kPa to 80 kPa, for example, 50 kPa, 60 kPa, 70 kPa or 80 kPa. If the suction force of the vacuum treatment is too large, the effect of avoiding damage to the heterojunction battery is reduced; if the suction force of the vacuum treatment is too small, the battery box will still be in contact with the air, and the probability of discharging water vapor in the battery box is small.

[0036] In one embodiment, the vacuum treatment time is 5s to 8s, for example, 5s, 6s, 7s or 8s. In this embodiment, the vacuum treatment suction force is 50kPa to 80kPa, and the vacuum treatment time is controlled to be 5s to 8s, so that when the vacuum is satisfied, damage to the heterojunction battery can be prevented, and specifically, hidden cracks in the heterojunction battery can be prevented.

[0037] In one embodiment, before the sealing bag is vacuumed, the method further comprises: placing a desiccant in the sealing bag. The desiccant can absorb moisture in the atmosphere to further suppress dark decay of the heterojunction battery.

[0038] In one embodiment, the desiccant includes anhydrous calcium chloride.

[0039] In one embodiment, the temperature of the low temperature environment is -20°C to -10°C, for example, -20°C, -15°C or -10°C. If the temperature of the low temperature environment is greater than -10°C, the effect of suppressing the dark decay of the heterojunction battery is weakened; if the temperature of the low temperature environment is less than -20°C, the heterojunction battery is prone to the risk of hidden cracks, causing damage to the heterojunction battery.

[0040] In one embodiment, the humidity of the low temperature environment is 60% to 75%, for example, 60%, 70% or 75%. If the humidity of the low temperature environment is greater than 75%, there is water vapor inside the battery box, which contacts the heterojunction battery, resulting in poor reliability of the heterojunction battery; if the humidity of the low temperature environment is less than 60%, the package may be too dry and the heterojunction battery may rupture.

[0041] In one embodiment, during the process of placing the sealed bag in a low-temperature environment for storage, the method further comprises: introducing a protective atmosphere into the low-temperature environment, so as to prevent the sealed bag from leaking, avoid oxidation of the transparent conductive layer in the heterojunction battery structure, and thus inhibit dark decay of the heterojunction battery.

[0042] In one embodiment, the protective atmosphere includes at least one of nitrogen, helium or argon. In other embodiments, the protective atmosphere includes other inert gases.

[0043] In one embodiment, the step of placing the heterojunction battery in the battery box includes: providing a plurality of heterojunction batteries and stacking the plurality of heterojunction batteries; during the stacking process, setting a spacer layer between adjacent heterojunction batteries, setting a buffer layer on the surface of the outermost heterojunction battery, and after setting the buffer layer, setting a support layer on the side of the buffer layer away from the heterojunction battery; after stacking and setting the spacer layer, the buffer layer and the support layer, placing the stacked heterojunction batteries in the battery box (i.e., placing the overall structure including the heterojunction batteries alternately spaced, the spacer layer between the heterojunction batteries, the outermost buffer layer and the support layer in the battery box). First, a spacer layer is set between adjacent heterojunction batteries to prevent friction between adjacent heterojunction batteries and avoid wear of the transparent conductive layer in the heterojunction battery structure; then a buffer layer is formed on the surface of the outermost heterojunction battery to prevent the outermost heterojunction battery from being impacted by external force and avoid damage to the heterojunction battery; after the buffer layer is formed, a support layer is formed on the side of the buffer layer away from the heterojunction battery. Placing the heterojunction battery in the battery box requires carrying and transferring the heterojunction battery. The support layer can ensure the horizontal force during the transfer process and provide a certain rigidity for the heterojunction battery.

[0044] In one embodiment, the spacer layer comprises sulfate paper; the buffer layer comprises a foam board; the support layer comprises a hard plastic board, and the Shore hardness of the hard plastic board is 80HD to 90HD, for example, 80HD, 85HD or 90HD.

[0045] The method for treating a heterojunction battery further includes: before performing the recovery treatment, taking out the heterojunction battery in the sealed bag placed in the low temperature environment for static treatment. The purpose of the static treatment is to restore the heterojunction battery from low temperature to normal temperature. The heterojunction battery restored to normal temperature is subjected to the recovery treatment so that the recovery treatment can take effect normally, and there is no need to perform additional output in the recovery treatment step to restore the heterojunction battery to room temperature.

[0046] In this embodiment, the static treatment is performed at room temperature, the temperature of the static treatment is not specifically described, and the static treatment time is 8 minutes to 15 minutes, for example, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes. In other embodiments, the static treatment time can be set according to actual conditions.

[0047] Specifically, the steps of performing an electric injection treatment on a heterojunction battery include: preheating the heterojunction battery; contacting the surface of the heterojunction battery with an electrode for electric injection treatment; and during the electric injection treatment, the heterojunction battery is also ventilated. Avoid local overheating of the heterojunction battery due to the thermal effect of the current. Specifically, for example, a blower is used to blow air into the processing space, and at the same time, the entire space and the heterojunction battery are blown to keep the space temperature and the battery temperature within a suitable range.

[0048] In one embodiment, the current of the electrical injection treatment is 6A to 10A, for example, 6A, 7A, 8A, 9A or 10A, the time is 10min to 15min, for example, 10min, 11min, 12min, 13min, 14min or 15min, and the temperature is 60℃ to 80℃, for example, 60℃, 70℃ or 80℃.

[0049] In this embodiment, during the process of performing electrical injection treatment on a heterojunction battery, the electrical injection treatment may be performed on a single heterojunction battery or on multiple heterojunction batteries. When performing electrical injection treatment on a single heterojunction battery, one side of the heterojunction battery contacts the copper electrode and the other side contacts the aluminum electrode; when performing electrical injection treatment on multiple heterojunction batteries, the multiple heterojunction batteries are stacked again, the outermost side of the heterojunction battery contacts the copper electrode and the other side contacts the aluminum electrode, that is, the top of the heterojunction battery contacts the copper electrode or the aluminum electrode, and the bottom of the heterojunction battery contacts the aluminum electrode or the copper electrode. It should be noted that the adjacent heterojunction batteries need to be aligned before stacking to ensure the uniformity of the electrical injection treatment of each heterojunction battery and avoid wear during the stacking of heterojunction batteries.

[0050] The step of performing light injection treatment on the heterojunction battery includes: preheating the heterojunction battery; then, performing light treatment on the heterojunction battery; during the light treatment, it also includes: purging the heterojunction battery. The temperature on the surface of the heterojunction battery is kept uniform to prevent the local temperature from being too high. Specifically, for example, a blower is used to blow air on the processing space and the surface of the heterojunction battery, and at the same time, the entire space and the heterojunction battery are blown to keep the space temperature and the battery temperature within a suitable range.

[0051] In one embodiment, the light intensity of the light treatment is 70kW / m2 to 90kW / m2, for example, 70kW / m2, 80kW / m2 or 90kW / m2, the temperature is 180°C to 190°C, for example, 180°C or 190°C, and the time is 2min to 4min, for example, 2min, 3min or 4min. The duration of the photothermal treatment is as long as possible within the allowable range and is adjusted according to actual needs.

[0052] In one embodiment, the light treatment uses one of halogen light, red light or infrared light. Among them, halogen light has a simple structure, easy brightness adjustment, and low energy consumption; red light has good penetration and good thermal effect.

[0053] In one embodiment, during the light injection process, a protective atmosphere is introduced to prevent oxidation of the surface of the heterojunction cell, wherein the protective atmosphere includes at least one of nitrogen, helium or argon.

[0054] In other embodiments, before placing the heterojunction battery in the battery box, the heterojunction battery is subjected to an electric injection treatment and / or a light injection treatment; after being placed in a static state, the heterojunction battery is subjected to an electric injection treatment and / or a light injection treatment again. The semiconductor functional layer can be further passivated to reduce dark decay to a certain extent, but due to the complexity of the steps and the long process time, the technical solution mentioned in this application is adopted in actual production.

[0055] In this embodiment, the processing method of the heterojunction battery further includes: forming a gate electrode on a side of the transparent conductive layer away from the semiconductor substrate layer. Specifically:

[0056] In one embodiment, before placing the heterojunction battery in the battery box, a gate line electrode is formed on a side of the transparent conductive layer away from the semiconductor substrate layer.

[0057] In another embodiment, after the heterojunction battery in the sealed bag placed in the low temperature environment is taken out for static treatment, before the heterojunction battery is restored, a gate line electrode is formed on a side of the transparent conductive layer away from the semiconductor substrate layer.

[0058] In the process of forming the gate line electrode on the side of the transparent conductive layer away from the semiconductor substrate layer, an uncured gate line electrode is first formed, and then the gate line electrode is cured to form a cured gate line electrode.

[0059] In one embodiment, the curing treatment temperature is 120°C to 140°C, such as 120°C, 130°C or 140°C, and the curing time is 5 min to 10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0060] In this embodiment, the gate electrode is made of copper. Since copper has poor heat resistance and is prone to warping due to large temperature differences, the curing temperature needs to be controlled within a range of 120° C. to 140° C. In other embodiments, the gate electrode is made of silver.

[0061] It can be understood that before placing the heterojunction battery in the battery box, a gate electrode is formed on the side of the transparent conductive layer away from the semiconductor substrate layer; then, during the vacuum treatment, vacuuming is performed by controlling the suction force, so that damage to the heterojunction battery can be avoided. Specifically, the risk of hidden cracks in the heterojunction battery and falling off of the gate electrode can be avoided; during the storage of the sealed bag in a low-temperature environment, a protective atmosphere is introduced into the low-temperature environment to avoid oxidation of the gate electrode in the heterojunction battery structure, thereby inhibiting dark decay of the heterojunction battery.

[0062] In another embodiment, after the heterojunction battery in the sealed bag placed in the low-temperature environment is taken out for static treatment, before the heterojunction battery is restored, a gate electrode is formed on the side of the transparent conductive layer away from the semiconductor substrate layer; then, during the vacuum treatment, the vacuuming is performed by controlling the suction force to avoid hidden cracks in the heterojunction battery; during the storage of the sealed bag in the low-temperature environment, a protective atmosphere is introduced into the low-temperature environment to avoid oxidation of the transparent conductive layer. Several specific embodiments and comparative examples are provided below to compare and illustrate the effects of the heterojunction battery treatment method provided by the present invention.

[0063] Example 1

[0064] This embodiment 1 is carried out with reference to the above-mentioned processing method of the heterojunction battery. Specifically, the processing method includes:

[0065] Placing the heterojunction battery in the battery box;

[0066] After placing the heterojunction battery in the battery box, placing the battery box in the sealed bag;

[0067] The sealing bag is subjected to a vacuum treatment so that the sealing bag is closely attached to the battery box;

[0068] After the sealed bag is vacuumed, the sealed bag is placed in a low temperature environment for storage.

[0069] In this embodiment, the suction force of the vacuum treatment is 60 kPa, and the time of the vacuum treatment is 8 s.

[0070] In this embodiment, the temperature of the low temperature environment is -10°C and the humidity is 75%.

[0071] Example 2

[0072] This embodiment 2 is carried out with reference to the above-mentioned processing method of the heterojunction battery. On the basis of embodiment 1, the processing method further includes: performing electrical injection processing on the heterojunction battery.

[0073] In this embodiment, the current of the electric injection treatment is 8A, the time is 15 minutes, and the temperature is 60°C.

[0074] Example 3

[0075] The difference between Example 3 and Example 2 is that:

[0076] Based on the embodiment 1, it also includes: performing light injection processing on the heterojunction battery.

[0077] In this embodiment, the light intensity of the light treatment is 90 kW / m2, the temperature is 190°C, and the time is 2 minutes.

[0078] Example 4

[0079] The difference between Example 4 and Example 2 or Example 3 is that:

[0080] On the basis of Example 1, it also includes: performing an electric injection process on the heterojunction battery, and then performing a light injection process on the heterojunction battery.

[0081] In this embodiment, the current of the electric injection treatment is 8A, the time is 15 minutes, and the temperature is 60°C.

[0082] In this embodiment, the light intensity of the light treatment is 90 kW / m2, the temperature is 190°C, and the time is 2 minutes.

[0083] Comparative Example 1

[0084] Comparative Example 1 provides a method for processing a heterojunction battery, comprising: placing the heterojunction battery in an atmospheric environment.

[0085] Comparative Example 2

[0086] Comparative Example 2 provides a method for processing a heterojunction battery, comprising: placing the heterojunction battery in a nitrogen environment.

[0087] Comparative Example 3

[0088] Comparative Example 3 provides a method for processing a heterojunction battery, comprising: placing the heterojunction battery in a vacuum environment.

[0089] Before the heterojunction battery treatment methods provided in Example 1 and Comparative Examples 1 to 3 were used for treatment, the heterojunction battery produced by the assembly line was immediately subjected to performance testing, and the following data were obtained:

[0090] Table 1

[0091]

[0092] After the heterojunction battery treatment method provided by Example 1 and Comparative Examples 1 to 3 was used for 7 days, the heterojunction battery was obtained for performance testing, and the following data were obtained:

[0093] Table 2

[0094]

[0095]

[0096] Wherein, ΔEff is the change in conversion efficiency.

[0097] Among them, ΔEff in Example 1 is a positive value, which means that the conversion efficiency of the heterojunction battery has increased slightly, which shows that the treatment method of the heterojunction battery provided by Example 1 can suppress the dark decay of the heterojunction battery. The corresponding comparative examples 1 and 3 are both negative values, and the amplitudes are relatively large, indicating that the dark decay has begun to affect and take effect.

[0098] After the heterojunction battery treatment method provided by Example 1 and Comparative Examples 1 to 3 was used for 14 days, the heterojunction battery was obtained for performance testing, and the following data were obtained:

[0099] Table 3

[0100]

[0101] After the heterojunction battery treatment method provided by Example 1 and Comparative Examples 1 to 3 was used for 21 days, the heterojunction battery was obtained for performance testing, and the following data were obtained:

[0102] Table 4

[0103]

[0104] According to the test results, combined with Tables 1 to 4, it can be seen that the values ​​of Example 1 have a small attenuation as the placement time increases, and the open circuit voltage, short circuit current, fill factor, etc. remain basically unchanged, especially ΔEff always maintains a positive value. The corresponding other comparative examples have obvious attenuation, with a significant decrease, especially ΔEff is always negative. It can be seen that the method of Example 1 can effectively suppress dark attenuation.

[0105] According to the results of Tables 1 to 4, it can be known that the dark decay degrees of the heterojunction battery are as follows from small to large: Example 1 (vacuum + low temperature environment), Comparative Example 2 (nitrogen environment), Comparative Example 3 (vacuum environment), Comparative Example 1 (atmospheric environment), that is, the processing method of the heterojunction battery provided in Example 1 of the present application can better suppress the dark decay of the heterojunction battery.

[0106] Further, on the basis of Example 1, specifically, on the basis of treating the heterojunction batteries for 7 days, another batch of batteries was treated using the heterojunction battery treatment method provided in Example 2 to Example 4.

[0107] After being treated in Example 1 for 7 days, the heterojunction battery was subjected to performance testing before being treated in Example 2 to Example 4, and the following data were obtained:

[0108] Table 5

[0109]

[0110] After the heterojunction battery treated in Example 1 for 7 days was treated in Example 2 to Example 4, a performance test was performed to obtain the following data:

[0111] Table 6

[0112]

[0113] The dark decay of heterojunction cells is small, which is conducive to the accuracy of subsequent sample testing. When sending samples for testing, cold chain transportation or dry ice is used, and bubble bags are placed outside the sealed bag for buffering.

[0114] According to Tables 5 and 6, it can be seen that after the heterojunction battery is preserved in Example 1 (vacuum + low temperature environment) and restored using Example 2 (electric injection treatment), Example 3 (light injection treatment), and Example 4 (electric injection treatment + light injection treatment), the performance of the heterojunction battery is improved.

[0115] In summary, the present application places the heterojunction battery in an environment where vacuum and low temperature coexist, which can suppress the reduction of the lifetime of minority carriers in the heterojunction battery, thereby suppressing the dark decay of the heterojunction battery, and the effect is the best compared with other methods of the prior art. By controlling the suction force during vacuuming and the temperature and humidity of the low temperature, damage to the heterojunction battery can be avoided; by selecting a refrigerator or freezer with a refrigeration function, complex factory service requirements are eliminated and maintenance costs are reduced. Afterwards, the heterojunction battery is restored through electrical injection treatment and / or light injection treatment to improve the quality of the heterojunction battery.

[0116] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for processing a heterojunction battery, characterized in that: The heterojunction battery comprises at least a semiconductor substrate layer, a semiconductor functional layer and a transparent conductive layer which are stacked; the method comprises: Provide sealed bags; Placing the heterojunction battery in a battery box; After placing the heterojunction battery in the battery box, placing the battery box in the sealed bag; The sealing bag is subjected to a vacuum treatment so that the sealing bag is closely attached to the battery box; After the sealed bag is vacuumed, the sealed bag is placed in a low temperature environment for storage; The temperature of the low temperature environment is -20°C to -10°C; It also includes performing a recovery process on the heterojunction battery before taking it out for use after being stored in a low-temperature environment; the recovery process includes: Electrical injection processing and / or optical injection processing.

2. The method for processing a heterojunction battery according to claim 1, characterized in that: The suction force of the vacuum treatment is 50kPa to 80kPa, and the time of the vacuum treatment is 5s to 8s.

3. The method for processing a heterojunction battery according to claim 1, characterized in that: Before vacuuming the sealed bag, the method further includes: placing a desiccant in the sealed bag; The desiccant includes anhydrous calcium chloride.

4. The method for processing a heterojunction battery according to claim 1, characterized in that: The humidity of the low temperature environment is 60% to 75%; During the process of storing the sealed bag in a low-temperature environment, the method further comprises: introducing a protective atmosphere into the low-temperature environment; the protective atmosphere comprises at least one of nitrogen, helium or argon.

5. The method for processing a heterojunction battery according to claim 1, characterized in that: The step of placing the heterojunction battery in the battery box includes: providing a plurality of heterojunction batteries and stacking the plurality of heterojunction batteries; During the stacking process, a spacer layer is arranged between adjacent heterojunction batteries, a buffer layer is arranged on the surface of the outermost heterojunction battery, and after the buffer layer is arranged, a support layer is arranged on a side of the buffer layer away from the heterojunction battery; After stacking and setting the spacing layer, buffer layer and support layer, the stacked heterojunction battery is placed in the battery box; wherein: the spacing layer includes sulfuric acid paper; the buffer layer includes a foam board; the support layer includes a hard plastic board, and the Shore hardness of the hard plastic board is 80HD~90HD.

6. The method for processing a heterojunction battery according to any one of claims 1 to 5, characterized in that: The method further comprises: before performing the recovery treatment, taking out the heterojunction battery in the sealed bag placed in the low temperature environment and performing a static treatment; The static treatment time is 8min to 15min.

7. The method for processing a heterojunction battery according to claim 1, characterized in that: The step of performing an electric injection treatment on the heterojunction battery comprises: preheating the heterojunction battery; contacting the surface of the heterojunction battery with an electrode for electric injection treatment; and during the electric injection treatment, ventilating the heterojunction battery; The electric injection treatment has a current of 6A to 10A, a time of 10min to 15min, and a temperature of 60°C to 80°C.

8. The method for processing a heterojunction battery according to claim 1, characterized in that: The step of performing light injection treatment on the heterojunction battery comprises: preheating the heterojunction battery; performing light treatment on the heterojunction battery; and during the light treatment, the heterojunction battery is purged; The light intensity of the light treatment is 70kW / m2 to 90kW / m2, the temperature is 180°C to 190°C, and the time is 2min to 4min; The light treatment uses one of halogen light, red light or infrared light.

9. The method for processing a heterojunction battery according to claim 6, characterized in that: The method further comprises: before placing the heterojunction battery in the battery box, forming a gate electrode on a side of the transparent conductive layer away from the semiconductor substrate layer, or, After the heterojunction battery in the sealed bag placed in the low temperature environment is taken out for static treatment, before the heterojunction battery is restored, a gate line electrode is formed on the side of the transparent conductive layer away from the semiconductor substrate layer.

10. The method for processing a heterojunction battery according to claim 9, characterized in that: Also includes: In the process of forming the gate line electrode on the side of the transparent conductive layer away from the semiconductor substrate layer, an uncured gate line electrode is first formed, and then the gate line electrode is cured to form a cured gate line electrode; The curing treatment is performed at a temperature of 120° C. to 140° C. and for a time of 5 min to 10 min.

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