CN116404051A - A kind of back contact solar cell and its manufacturing method, photovoltaic module - Google Patents

Abstract

The invention discloses a back-contact solar cell, a manufacturing method thereof, and a photovoltaic module, and relates to the field of photovoltaic technology, so as to reduce or eliminate laser energy when a laser etching process is used to isolate an N region and a P region included in a back-contact solar cell. Damage to back contact solar cells. The back contact solar cell includes: a semiconductor substrate, a transparent conductive layer and an insulating light-absorbing layer. The semiconductor substrate has opposing first and second sides. The second surface has N-type regions and P-type regions distributed alternately at intervals, and an isolation region between each N-type region and the corresponding P-type region. The transparent conductive layer covers the second surface. Each isolation region is provided with an isolation groove penetrating through the transparent conductive layer, and the isolation groove is used to isolate the part of the transparent conductive layer on the N-type region from the part of the transparent conductive layer on the P-type region. The insulating light-absorbing layer is at least located at the bottom of the isolation groove, and the width of the insulating light-absorbing layer is greater than or equal to the width of the isolation groove.

Description

A kind of back contact solar cell and its manufacturing method, photovoltaic module

technical field

The invention relates to the field of photovoltaic technology, in particular to a back-contact solar cell, a manufacturing method thereof, and a photovoltaic module.

Background technique

Back-contact solar cells refer to solar cells in which the emitter and metal contacts are on the back of the cell, and the front is not blocked by metal electrodes. Compared with solar cells with shaded on the front, back-contact solar cells have higher short-circuit current and photoelectric conversion efficiency, and are currently one of the technical directions for realizing high-efficiency crystalline silicon cells.

However, in the existing manufacturing method, the process for isolating the N region and the P region included in the back contact solar cell is easy to cause damage to the back contact solar cell, resulting in a decrease in the yield of the back contact solar cell, which is not conducive to improving the back contact solar cell. Electrical properties of contact solar cells.

Contents of the invention

The purpose of the present invention is to provide a back contact solar cell and its manufacturing method, photovoltaic module, to reduce or eliminate the laser energy when the N region and the P region included in the back contact solar cell are separated by using a laser etching process Cause damage to the back contact solar cell, improve the yield rate of the back contact solar cell, and then help to improve the electrical performance of the back contact solar cell.

In a first aspect, the present invention provides a back-contact solar cell, which includes: a semiconductor substrate, a transparent conductive layer and an insulating light-absorbing layer.

The aforementioned semiconductor substrate has opposite first and second faces. The second surface has N-type regions and P-type regions distributed alternately at intervals, and an isolation region between each N-type region and the corresponding P-type region. The transparent conductive layer covers the second surface. Each isolation region is provided with an isolation groove penetrating through the transparent conductive layer, and the isolation groove is used to isolate the part of the transparent conductive layer on the N-type region from the part of the transparent conductive layer on the P-type region. The insulating light-absorbing layer is at least located at the bottom of the isolation groove, and the width of the insulating light-absorbing layer is greater than or equal to the width of the isolation groove.

In the case of adopting the above-mentioned technical solution, in the back-contact solar cell provided by the present invention, the second surface of the semiconductor substrate has N-type regions and P-type regions alternately distributed, and each N-type region and the corresponding P-type region isolation area between. The isolation region can isolate the N-type region and the P-type region of opposite conductivity types, inhibit the recombination of carriers at the lateral junction of the two, and improve the photoelectric conversion efficiency of the back contact solar cell. In addition, the transparent conductive layer included in the back contact solar cell covers the above-mentioned second surface. Wherein, the part of the transparent conductive layer located on the N-type region can reduce the contact barrier between the N-type region and the first electrode, which is beneficial to the derivation of electrons. The part of the transparent conductive layer on the P-type region can reduce the contact barrier between the P-type region and the second electrode, which is beneficial to the derivation of holes. Based on this, an isolation groove penetrating through the transparent conductive layer is formed on each isolation region, and the isolation groove is used to isolate the part of the transparent conductive layer on the N-type region from the part of the transparent conductive layer on the P-type region, preventing The back contact solar cell is short-circuited, and the electrical stability of the back contact solar cell is improved.

Secondly, the back contact solar cell further includes an insulating light-absorbing layer at least at the bottom of the isolation groove. Based on this, since the insulating light-absorbing layer is a non-conductive film layer, the part of the transparent conductive layer located on the N-type region and the part of the transparent conductive layer located on the P-type region cannot be conducted through the insulating light-absorbing layer, which can prevent back contact with the solar cell. short circuit. At the same time, the insulating light-absorbing layer also has light-absorbing properties. In this case, after the entire transparent conductive layer covering the second surface is formed, even if an isolation groove penetrating through the transparent conductive layer is formed on each isolation region by a laser etching process, the existence of the insulating light-absorbing layer can While ensuring that the transparent conductive layer is completely carved through, the damage caused by the laser to the underlying film layer is reduced or even eliminated, and the yield rate of the back contact solar cell is improved. At the same time, it can also solve the problems of high manufacturing cost and unsuitability for large-scale mass production caused by the combination of photolithography and wet etching or ink printing and wet etching in the prior art. The manufacturing cost of contact solar cells, and the mass-producibility of improving back contact solar cells.

As a possible implementation manner, the width of the insulating light-absorbing layer is greater than the width of the isolation groove. The insulating light-absorbing layer is also located between the part of the transparent conductive layer and the portion of the semiconductor substrate corresponding to the isolation region.

In the case of adopting the above technical solution, in the actual manufacturing process, the width of the isolation groove is the etching width of the transparent conductive layer by the laser etching process. Based on this, when the width of the insulating light-absorbing layer is greater than the width of the isolation groove, the width of the insulating light-absorbing layer is also greater than the etching width of the transparent conductive layer by the laser etching process. Moreover, the insulating light-absorbing layer is also located on the part of the transparent conductive layer and the part of the semiconductor substrate corresponding to the isolation region. At this time, the existence of the insulating light-absorbing layer can reduce or eliminate the damage caused by laser etching on the part of the semiconductor substrate corresponding to the bottom of the isolation groove and the part near the corresponding isolation groove, and further improve the yield of the back contact solar cell.

As a possible implementation manner, along the width direction of the isolation groove, the thicknesses of the edge regions on both sides of the insulating light-absorbing layer gradually decrease.

In the case of adopting the above-mentioned technical solution, in the actual manufacturing process, when the isolation groove that runs through the entire layer of the transparent conductive layer covered on the second surface is formed by using the laser etching process, the part of the laser on the transparent conductive layer corresponding to the middle part of the isolation groove The etching strength is higher. Based on this, when the thickness of the edge regions on both sides of the insulating light-absorbing layer gradually decreases along the width direction of the isolation groove, it means that the thickness of the central region of the insulating light-absorbing material for making the insulating light-absorbing layer along the width direction is relatively large. Correspondingly, the central region of the insulating light-absorbing material along the width direction has a stronger light-absorbing characteristic, thereby further reducing or even eliminating damage to the film layer of the semiconductor substrate at the bottom of the isolation groove caused by laser light. In addition, along the width direction of the isolation groove, the thickness of the edge regions on both sides of the insulating light-absorbing layer gradually decreases, which can also reduce the consumption of consumables in the edge regions on both sides of the insulating light-absorbing layer, and reduce the manufacturing cost of the insulating light-absorbing layer. At the same time, the surface of the side of the insulating light-absorbing material facing away from the transparent conductive layer can also be convex, so that the light-absorbing area of the insulating light-absorbing material facing away from the transparent conductive layer can be increased, and the unit of the insulating light-absorbing material facing away from the transparent conductive layer can be reduced. The amount of light absorption can reduce the damage degree of the laser etching process to the insulating light-absorbing material that makes the insulating light-absorbing layer, and finally can reduce the manufacturing thickness of the insulating light-absorbing material, and further reduce the consumption of insulating light-absorbing materials.

As a possible implementation manner, at least one light-trapping structure is provided on the side of the insulating light-absorbing layer in contact with the transparent conductive layer.

In the case of adopting the above-mentioned technical solution, the above-mentioned light-trapping structure can allow more laser light to be projected into the insulating light-absorbing material for manufacturing the insulating light-absorbing layer during the process of forming the isolation groove through the transparent conductive layer by the laser etching process, preventing The scattering of laser light affects the morphology of the side wall of the transparent conductive layer corresponding to the isolation groove, so as to ensure that the morphology of the two side walls of the transparent conductive layer along the width direction of the isolation groove meets the working requirements, and then ensure that the transparent conductive layer along the width of the isolation groove Each part of the region in the direction has good conductive properties, which is conducive to improving the photoelectric conversion efficiency of the back contact solar cell.

As a possible implementation manner, the above light trapping structure is a recessed structure recessed into the insulating light absorbing layer. In this case, in the actual manufacturing process, an insulating light-absorbing material with a light-trapping structure whose shape meets the work requirements can be formed on the isolation region by only using methods such as screen printing or inkjet, and there is no need to form the above-mentioned The light-trapping structure adds additional processing steps, simplifies the manufacturing process of the insulating light-absorbing material for manufacturing the insulating light-absorbing layer, and reduces the difficulty of manufacturing the insulating light-absorbing material.

As a possible implementation manner, the above-mentioned concave structure is a hemispherical concave structure.

In the case of adopting the above technical solution, the shape of the hemispherical concave structure is relatively regular, and there is no need to strictly require the precision of the manufacturing process in order to form the light-trapping structure with a complex shape, which further reduces the difficulty of manufacturing the insulating light-absorbing material. In addition, the hemispherical concave structure is a highly symmetrical concave structure, and the surface morphology of each part of the inwardly concave surface is the same, so that each part of the insulating light-absorbing material has an excellent light-trapping effect, and further ensures transparency. The sidewall morphology of the conductive layer along the width direction meets the working requirements.

As a possible implementation manner, the width of the insulating light-absorbing layer is greater than or equal to 5 μm and less than or equal to 5 mm.

In the case of adopting the above technical solution, as mentioned above, the width of the insulating light-absorbing layer is greater than or equal to the width of the isolation groove. Based on this, when the width of the insulating light-absorbing layer is within the above range, it can prevent the part of the transparent conductive layer located on the N-type region from being difficult to communicate with the transparent conductive layer due to the smaller width of the insulating light-absorbing layer and the smaller width of the isolation groove. The portion of the layer that lies on the P-type region is separated to suppress leakage. At the same time, it can also prevent the consumption of consumable materials for the insulating light-absorbing layer due to the large width of the insulating light-absorbing layer, and reduce the manufacturing cost of the insulating light-absorbing material for manufacturing the insulating light-absorbing layer. In addition, it can also prevent the area of the N-type region and the P-type region covered by the transparent conductive layer from being reduced due to the larger width of the insulating light-absorbing layer, resulting in a larger width of the isolation groove, which in turn causes the semiconductor substrate to be in the working state. Carriers cannot be exported by the transparent conductive layer in time, so the width of the insulating light-absorbing layer within the above range can also improve the photoelectric conversion efficiency of the back contact solar cell.

As a possible implementation manner, the material of the insulating light-absorbing layer is ink, photoresist or UV curable glue.

In the case of adopting the above technical solution, the ink, photoresist and UV curable glue all have good light-absorbing characteristics, so if the material of the above-mentioned insulating light-absorbing layer is one of the above-mentioned materials, it can be formed by using a laser etching process. In the process of isolating the groove, it is ensured that the insulating light-absorbing material of the insulating light-absorbing layer can be manufactured to reduce or even eliminate the damage caused by the laser to the part of the semiconductor substrate corresponding to the isolation region.

As a possible implementation manner, the above conductor base includes: a semiconductor substrate, a first semiconductor stack and a second semiconductor stack. The above-mentioned first semiconductor stack is formed at least on a portion of the semiconductor substrate corresponding to the N-type region. Along the direction away from the semiconductor substrate, the first semiconductor stack includes a first passivation layer and an N-type doped semiconductor layer on the first passivation layer. The above-mentioned second semiconductor stack is formed at least on a portion of the semiconductor substrate corresponding to the P-type region. Along the direction away from the semiconductor substrate, the second semiconductor stack includes a second passivation layer and a P-type doped semiconductor layer on the second passivation layer.

In the case of adopting the above technical solution, both the first semiconductor stack and the second semiconductor stack are selective contact structures. Based on this, because the selective contact structure has excellent interface passivation effect and selective collection of carriers, the first semiconductor stack and the second semiconductor stack that are both selective contact structures can further improve the performance of back contact solar cells. photoelectric conversion efficiency. In addition, the chemical properties of the above-mentioned first passivation layer and the second passivation layer are prone to change in a high-temperature scene. For example: when at least one of the first passivation layer and the second passivation layer is an intrinsic amorphous silicon layer, in the case of using a laser etching process to form isolation grooves, the high-temperature laser will make the intrinsic amorphous silicon The portion of the layer located on or near the isolation region is prone to form polysilicon or single crystal silicon, which affects the interface passivation effect of this portion and the selective collection of carriers. Based on this, the existence of the insulating light-absorbing layer can reduce or even eliminate laser damage to the first passivation layer and/or the second passivation layer, ensuring excellent working performance of the back contact solar cell.

As a possible implementation, the above-mentioned first semiconductor stack is further formed on a portion of the semiconductor substrate corresponding to the isolation region, and the second semiconductor stack is also formed above the portion of the first semiconductor stack corresponding to the isolation region; or, The second semiconductor stack is also formed on the portion of the semiconductor substrate corresponding to the isolation region, and the first semiconductor stack is also formed above the portion of the second semiconductor stack corresponding to the isolation region. In this case, the above-mentioned semiconductor substrate further includes an insulating layer located between the part of the first semiconductor stack corresponding to the isolation region and the part of the second semiconductor stack corresponding to the isolation region.

In the case of adopting the above technical solution, the carriers of the corresponding conductivity type can respectively pass through the first passivation layer and the second passivation layer through the tunneling effect, and be transported by the N-type doped semiconductor layer or the P-type doped semiconductor layer. collected. Based on this, when a portion of one of the first semiconductor stack and a second semiconductor stack corresponding to the isolation region is located on a portion of the other corresponding to the isolation region, the insulating layer can separate the portion of the first semiconductor stack corresponding to the isolation region The portion corresponding to the isolation region of the second semiconductor stack is isolated to prevent carrier recombination at the longitudinal junction between the first semiconductor stack and the second semiconductor stack, and further improve the photoelectric conversion efficiency of the back contact solar cell.

In a second aspect, the present invention also provides a photovoltaic module, which includes the back contact solar cell provided in the above first aspect and various implementations thereof.

For the beneficial effects of the second aspect of the present invention, reference may be made to the analysis of the beneficial effects in the first aspect and its various implementation manners, and details are not described here.

In a third aspect, the present invention also provides a method for manufacturing a back-contact solar cell. The method for manufacturing a back-contact solar cell includes: firstly, forming a semiconductor substrate. The semiconductor substrate has opposing first and second sides. The second surface has N-type regions and P-type regions distributed alternately at intervals, and an isolation region between each N-type region and the corresponding P-type region. Next, an insulating light-absorbing material is formed on at least part of the isolation region. Next, a transparent conductive layer covering the N-type region, the P-type region and the insulating light-absorbing material is formed. Then, using a laser etching process, an isolation groove penetrating through the transparent conductive layer is formed on each isolation region, and the remaining insulating light-absorbing material forms an insulating light-absorbing layer. The isolation groove is used to isolate the part of the transparent conductive layer on the N-type region from the part of the transparent conductive layer on the P-type region. The insulating light-absorbing layer is at least located at the bottom of the isolation groove, and the width of the insulating light-absorbing layer is greater than or equal to the width of the isolation groove.

As a possible implementation manner, the top surface area of the part of the insulating light-absorbing material corresponding to the isolation groove is larger than the bottom surface area of the part of the insulating light-absorbing material corresponding to the isolation groove.

As a possible implementation manner, along the width direction of the isolation groove, the average thickness of the middle region of the insulating light-absorbing material is greater than the average thickness of the edge regions on both sides of the insulating light-absorbing material.

As a possible implementation manner, a plurality of light-trapping structures are provided on the side of the above-mentioned insulating light-absorbing material away from the semiconductor substrate.

As a possible implementation manner, the multiple light trapping structures are evenly distributed on the side of the insulating light absorbing material away from the semiconductor substrate. In this case, the light trapping effect of each part of the insulating light-absorbing material is roughly the same, thereby ensuring that the area of the semiconductor substrate covered by each part of the insulating light-absorbing material can be effectively protected, and further improving the yield of the back contact solar cell.

As a possible implementation manner, a screen printing process or an inkjet printing process is used to form an insulating light-absorbing material.

In the case of adopting the above technical solution, the screen printing process and the inkjet printing process are conventional processes for manufacturing back-contact solar cells. Based on this, the insulating light-absorbing material can be formed by using a screen printing process or an ink-jet printing process, without using separate manufacturing equipment for forming the insulating light-absorbing material. In other words, the manufacturing method of the back-contact solar cell provided by the present invention is compatible with the conventional manufacturing process and equipment of the conventional back-contact solar cell, reduces the manufacturing difficulty of the back-contact solar cell, and improves the manufacturing efficiency.

As a possible implementation manner, the minimum thickness of the part of the insulating light-absorbing material corresponding to the isolation groove is greater than or equal to 0.05 μm and less than or equal to 100 μm.

In the case of adopting the above technical solution, the minimum thickness of the part of the above-mentioned insulating light-absorbing material corresponding to the isolation groove is within the above-mentioned range, which can prevent the part of the insulating light-absorbing material corresponding to the isolation groove from not completely cutting through the transparent conductive layer due to the small minimum thickness. All layers are etched away by laser before the entire etching process to ensure that the insulating light-absorbing material can protect the part of the semiconductor substrate corresponding to the isolation region during the entire etching process, and further ensure that the back contact solar cell has a higher yield. At the same time, it can also prevent the use of consumables of the insulating light-absorbing material from being large due to the above-mentioned large minimum thickness, which is beneficial to reducing the manufacturing cost of the insulating light-absorbing material.

As a possible implementation manner, the foregoing formation of a semiconductor substrate includes: providing a semiconductor substrate. Next, a first semiconductor stack is formed at least on a portion of the semiconductor substrate corresponding to the N-type region. Along the direction away from the semiconductor substrate, the first semiconductor stack includes a first passivation layer and an N-type doped semiconductor layer on the first passivation layer. Next, a second semiconductor stack is formed at least on a portion of the semiconductor substrate corresponding to the P-type region. Along the direction away from the semiconductor substrate, the second semiconductor stack includes a second passivation layer and a P-type doped semiconductor layer on the second passivation layer. The semiconductor base includes a semiconductor substrate, a first semiconductor stack and a second semiconductor stack.

As a possible implementation, the above-mentioned first semiconductor stack is further formed on a portion of the semiconductor substrate corresponding to the isolation region, and the second semiconductor stack is also formed above the portion of the first semiconductor stack corresponding to the isolation region; or, The second semiconductor stack is also formed on the portion of the semiconductor substrate corresponding to the isolation region, and the first semiconductor stack is also formed above the portion of the second semiconductor stack corresponding to the isolation region. In the above case, between the formation of the first semiconductor stack on at least the portion of the semiconductor substrate corresponding to the N-type region and the formation of the second semiconductor stack on at least the portion of the semiconductor substrate corresponding to the P-type region, the rear The manufacturing method of the contact solar cell further includes: forming an insulating layer between the portion of the first semiconductor stack corresponding to the isolation region and the portion of the second semiconductor stack corresponding to the isolation region.

For the beneficial effects of the third aspect of the present invention and its various implementations, reference may be made to the analysis of the beneficial effects of the first aspect and its various implementations, which will not be repeated here.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is a structural longitudinal cross-sectional schematic diagram of a back contact solar cell provided by an embodiment of the present invention;

FIG. 2 is an enlarged schematic diagram of a structure at the isolation groove in an embodiment of the present invention;

3 is an enlarged schematic view of another structure at the isolation groove in the embodiment of the present invention;

FIG. 4 is an enlarged schematic view of yet another structure at the isolation groove in the embodiment of the present invention;

Fig. 5 is a structural longitudinal cross-sectional schematic diagram 1 of the back contact solar cell provided by the embodiment of the present invention during the manufacturing process;

Fig. 6 is a schematic longitudinal cross-sectional view II of the structure of the back contact solar cell in the manufacturing process provided by the embodiment of the present invention;

Fig. 7 is a schematic longitudinal cross-sectional view III of the structure of the back contact solar cell in the manufacturing process provided by the embodiment of the present invention;

Fig. 8 is a schematic longitudinal cross-sectional view IV of the structure of the back contact solar cell in the manufacturing process provided by the embodiment of the present invention;

Fig. 9 is a schematic longitudinal cross-sectional schematic view 5 of the structure of the back contact solar cell in the manufacturing process provided by the embodiment of the present invention;

Fig. 10 is a schematic longitudinal cross-sectional view six of the structure of the back contact solar cell in the manufacturing process provided by the embodiment of the present invention;

Fig. 11 is a schematic longitudinal cross-sectional view VII of the structure of the back contact solar cell in the manufacturing process provided by the embodiment of the present invention;

12 is a schematic longitudinal cross-sectional view of a structure after forming an insulating light-absorbing material in an embodiment of the present invention;

13 is a schematic longitudinal cross-sectional view of another structure after forming an insulating light-absorbing material in an embodiment of the present invention;

14 is a schematic longitudinal cross-sectional view of yet another structure after forming an insulating light-absorbing material in an embodiment of the present invention;

Fig. 15 is a schematic longitudinal cross-sectional view eighth of the structure of the back contact solar cell during the manufacturing process provided by the embodiment of the present invention;

16 is a schematic longitudinal cross-sectional view of a structure after forming a transparent conductive material in an embodiment of the present invention;

17 is a schematic longitudinal cross-sectional view of another structure after forming a transparent conductive material in the embodiment of the present invention;

18 is a schematic longitudinal cross-sectional view of another structure after forming a transparent conductive material in the embodiment of the present invention;

Fig. 19 is a schematic longitudinal cross-sectional view nine of the structure of the back contact solar cell in the manufacturing process provided by the embodiment of the present invention;

FIG. 20 is a schematic longitudinal cross-sectional view of the structure of the back contact solar cell provided by the embodiment of the present invention during the manufacturing process.

Reference numerals: 1 is a semiconductor substrate, 2 is a first passivation material layer, 3 is an N-type doped semiconductor material layer, 4 is an insulating material layer, 5 is a mask layer, 6 is a first passivation layer, 7 is an N-type doped semiconductor layer, 8 is a second passivation material layer, 9 is a P-type doped semiconductor material layer, 10 is a passivation anti-reflection layer, 11 is a second passivation layer, and 12 is a P-type doped semiconductor layer 13 is an insulating layer, 14 is an insulating light-absorbing material, 15 is a transparent conductive layer, 16 is an isolation groove, 17 is an insulating light-absorbing layer, 18 is a first electrode, and 19 is a second electrode.

Detailed ways

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be understood, however, that these descriptions are exemplary only, and are not intended to limit the scope of the present disclosure. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the present disclosure.

Various structural schematic diagrams according to embodiments of the present disclosure are shown in the accompanying drawings. The figures are not drawn to scale, with certain details exaggerated and possibly omitted for clarity of presentation. The shapes of the various regions and layers shown in the figure, as well as their relative sizes and positional relationships are only exemplary, and may deviate due to manufacturing tolerances or technical limitations in practice, and those skilled in the art will Regions/layers with different shapes, sizes, and relative positions can be additionally designed as needed.

In the context of the present disclosure, when a layer/element is referred to as being "on" another layer/element, the layer/element may be directly on the other layer/element, or there may be intervening layers/elements in between. element. Additionally, if a layer/element is "on" another layer/element in one orientation, the layer/element can be located "below" the other layer/element when the orientation is reversed. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more than one, unless otherwise clearly and specifically defined.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connection, or integral connection; can be mechanical connection or electrical connection; can be direct connection or indirect connection through an intermediary, and can be the internal communication of two elements or the interaction relationship between two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

At present, as a new energy alternative, solar cells are used more and more widely. Among them, a photovoltaic solar cell is a device that converts the light energy of the sun into electrical energy. Specifically, the solar cell uses the principle of photovoltaics to generate carriers, and then uses electrodes to extract the carriers, so as to facilitate the effective use of electric energy.

When the solar cell includes both positive and negative electrodes on the back side of the solar cell, the solar cell is a back-contact solar cell. Existing back contact solar cells include metal wrap through (abbreviated as MWT) cells and interdigitated back contact (abbreviated as IBC) cells. Among them, the biggest feature of the IBC battery is that the emitter and the metal contact are on the back of the battery, and the front is not affected by the shielding of the metal electrode, so it has a higher short-circuit current Isc. At the same time, the back of the IBC battery can allow wider metal grid lines to reduce the series resistance Rs, thereby increasing the fill factor FF. Moreover, this kind of unobstructed battery not only has high conversion efficiency, but also looks more beautiful. At the same time, components with full back electrodes are easier to assemble, so IBC batteries are currently one of the technical directions for realizing high-efficiency crystalline silicon batteries.

In practical applications, back contact solar cells usually include a semiconductor substrate and a transparent conductive layer. Wherein, the semiconductor substrate has a first surface and a second surface opposite to each other. Along a direction parallel to the second surface, the second surface has N-type regions and P-type regions distributed alternately and at intervals, and an isolation region between each N-type region and P-type region. The above-mentioned transparent conductive layer covers the second surface. Moreover, an isolation groove at least penetrating through the transparent conductive layer is formed on each isolation region, and the isolation groove is used to isolate the part of the transparent conductive layer on the N-type region from the part of the transparent conductive layer on the P-type region. Based on this, in an actual manufacturing process, after the semiconductor substrate is formed, a process such as physical vapor deposition is usually used to form a transparent conductive material covering the second surface. Then pattern the part of the transparent conductive material located on the isolation region, so as to completely remove at least the part of the transparent conductive material corresponding to the space where the isolation groove is located, and realize the isolation of the N-type region and the P-type region. Wherein, there are generally three ways to realize the above patterning treatment: photolithography combined with wet etching, ink printing combined with wet etching, and laser etching.

However, the process costs of the above photolithography combined with wet etching and ink printing combined with wet etching are relatively high and are not suitable for mass production. In addition, in the process of implementing the above patterning process by means of laser etching, in order to suppress electric leakage, it is necessary to completely remove at least the part of the transparent conductive material corresponding to the space where the isolation groove is located. However, the temperature of the laser is higher in the laser etching method. In order to achieve the above purpose, the film layer at the bottom of the isolation groove will be affected by the laser energy, causing the above film layer to be damaged, which will eventually lead to the yield of the back contact solar cell. It is not conducive to improving the electrical performance of the back contact solar cell.

In order to solve the above technical problems, in a first aspect, an embodiment of the present invention provides a back contact solar cell. As shown in FIG. 1 , the back contact solar cell includes: a semiconductor substrate, a transparent conductive layer 15 and an insulating light-absorbing layer 17 . The aforementioned semiconductor substrate has opposite first and second faces. The second surface has N-type regions and P-type regions distributed alternately at intervals, and an isolation region between each N-type region and the corresponding P-type region. The transparent conductive layer 15 covers the second surface. Each isolation region is provided with an isolation groove 16 penetrating through the transparent conductive layer 15 , and the isolation groove 16 is used to isolate the part of the transparent conductive layer 15 located on the N-type region from the part of the transparent conductive layer 15 located on the P-type region. As shown in FIGS. 1 to 4 , the insulating light-absorbing layer 17 is at least located at the bottom of the isolation groove 16 , and the width of the insulating light-absorbing layer 17 is greater than or equal to the width of the isolation groove 16 .

Specifically, the specific structure of the above-mentioned semiconductor substrate can be set according to actual application scenarios, and is not specifically limited here.

Wherein, when the back contact solar cell provided by the embodiment of the present invention is a back contact cell without a passivation contact structure formed on the backlight surface, the above-mentioned semiconductor substrate may only include a semiconductor substrate, an N-type doped semiconductor layer and a P-type doped semiconductor layer. doped semiconductor layer. The N-type doped semiconductor layer is formed on the part of the semiconductor substrate corresponding to the N-type region, or, the N-type doped semiconductor layer can also be formed in the part of the semiconductor substrate corresponding to the N-type region. The above-mentioned P-type doped semiconductor layer is formed on the part of the semiconductor substrate corresponding to the P-type region, or, the P-type doped semiconductor layer can also be formed in the part of the semiconductor substrate corresponding to the P-type region. In this case, the N-type region of the semiconductor substrate is the region where the N-type doped semiconductor layer is located, and the P-type region of the semiconductor substrate is the region where the P-type semiconductor layer is located.

Specifically, the aforementioned semiconductor substrate may be a substrate of semiconductor material such as a silicon substrate, a silicon germanium substrate, or a germanium substrate. In terms of conductivity type, the semiconductor substrate can be an intrinsic conductive substrate, an N-type conductive substrate or a P-type conductive substrate. Preferably, the semiconductor substrate is an N-type conductive substrate or a P-type conductive substrate. Compared with intrinsically conductive substrates, N-type conductive substrates or P-type conductive substrates have higher conductivity, which is conducive to reducing the series resistance of back-contact solar cells and improving the photoelectric conversion efficiency of back-contact solar cells. Secondly, when the above-mentioned N-type doped semiconductor layer and P-type doped semiconductor layer are respectively formed on the parts of the semiconductor substrate corresponding to the N-type region and the P-type region, the N-type doped semiconductor layer and the P-type doped semiconductor layer The material can be silicon, silicon germanium, germanium or silicon carbide, etc. In terms of the internal arrangement of the substance, the N-type doped semiconductor layer and the P-type doped semiconductor layer can be amorphous, microcrystalline, single crystal, nanocrystalline or polycrystalline etc.

In addition, the back contact solar cell provided by the embodiment of the present invention may also be a back contact solar cell with a passivation contact structure formed on the backlight surface. In this case, only the N-type region of the semiconductor substrate may be formed with a corresponding passivation contact structure, or only the P-type region of the semiconductor substrate may be formed with a corresponding passivation contact structure, or it may also be the semiconductor substrate Corresponding passivation contact structures are formed in the N-type region and the P-type region.

In the following, the N-type region and the P-type region of the semiconductor base are both formed with corresponding passivation contact structures as an example: As shown in Figure 1, the semiconductor base includes a semiconductor substrate 1, a first semiconductor stack and a second semiconductor stack layer. The above-mentioned first semiconductor stack is formed at least on the portion of the semiconductor substrate 1 corresponding to the N-type region. Along the direction away from the semiconductor substrate 1 , the first semiconductor stack includes a first passivation layer 6 and an N-type doped semiconductor layer 7 on the first passivation layer 6 . The above-mentioned second semiconductor stack is formed at least on the portion of the semiconductor substrate 1 corresponding to the P-type region. Along the direction away from the semiconductor substrate 1 , the second semiconductor stack includes a second passivation layer 11 and a P-type doped semiconductor layer 12 on the second passivation layer 11 . In this case, both the first semiconductor stack and the second semiconductor stack are selective contact structures. Based on this, because the selective contact structure has excellent interface passivation effect and selective collection of carriers, the first semiconductor stack and the second semiconductor stack that are both selective contact structures can further improve the performance of back contact solar cells. photoelectric conversion efficiency.

Wherein, the N-type region of the semiconductor substrate is the region where the N-type doped semiconductor layer is in contact with the transparent conductive layer, and the P-type region of the semiconductor substrate is the region where the P-type semiconductor layer is in contact with the transparent conductive layer. An isolation region is a region between each N-type region and an adjacent P-type region.

Specifically, in terms of materials, the materials of the first passivation layer, the N-type doped semiconductor layer, the second passivation layer, and the P-type doped semiconductor layer can be selected according to the passivation formed by the N-type region and the P-type region. The type of chemical contact structure is determined. For example: when the passivation contact structure formed in the N-type region of the semiconductor substrate is a tunneling passivation contact structure, the first passivation layer is a tunneling passivation layer, and the material of the tunneling passivation layer may include silicon oxide, One or more of aluminum oxide, titanium oxide, hafnium dioxide, gallium oxide, tantalum pentoxide, niobium pentoxide, silicon nitride, silicon carbonitride, aluminum nitride, titanium nitride, and titanium nitride carbide. At this time, the N-type doped semiconductor layer is an N-type doped polysilicon layer. Another example: when the passivation contact structure formed in the N-type region of the semiconductor substrate is a heterogeneous contact structure, the first passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, or an intrinsic microcrystalline silicon layer. mixed layer with amorphous silicon. At this time, the N-type doped silicon layer is an N-type amorphous silicon layer, an N-type microcrystalline silicon layer, or a mixed layer of N-type amorphous silicon and microcrystalline silicon.

For the materials of the above-mentioned second passivation layer and the P-type doped semiconductor layer, reference may be made to the material analysis of the first passivation layer and the N-type doped semiconductor layer, which will not be repeated here.

Secondly, in terms of the type of passivation, when the N-type region and the P-type region of the semiconductor substrate are both formed with corresponding passivation contact structures, the types of the passivation contact structures formed by the N-type region and the P-type region can be the same. Exemplarily, both the N-type region and the P-type region of the semiconductor substrate may be formed with a tunnel passivation contact structure. Alternatively, both the N-type region and the P-type region of the semiconductor substrate may be formed with a heterogeneous contact structure.

Of course, when the N-type region and the P-type region of the semiconductor substrate are both formed with corresponding passivation contact structures, the types of the passivation contact structures formed by the N-type region and the P-type region may also be different. Exemplarily, one of the N-type region and the P-type region of the semiconductor substrate is formed with a tunneling passivation contact structure, and the other is formed with a heterogeneous contact structure.

In terms of size, the thicknesses of the above-mentioned first passivation layer, N-type doped semiconductor layer, second passivation layer and P-type doped semiconductor layer can be determined according to the material of each layer above and the actual application scenario , not specifically limited here.

For example: when the first passivation layer and the second passivation layer are intrinsic amorphous silicon layers, the thickness of the first passivation layer and the second passivation layer may be 3 nm to 15 nm.

For example: when the N-type doped semiconductor layer is an N-type doped amorphous silicon layer, the thickness of the N-type doped semiconductor layer is 3 nm to 20 nm.

For example: when the P-type doped semiconductor layer is a P-type doped amorphous silicon layer, the thickness of the P-type doped semiconductor layer is 3 nm to 20 nm.

In addition, in the case that the semiconductor base includes the above-mentioned semiconductor substrate, the first semiconductor stack and the second semiconductor stack, the first semiconductor stack may be formed only on the portion of the semiconductor substrate corresponding to the N-type region. Alternatively, as shown in FIG. 1 , the first semiconductor stack can also be formed on a portion of the semiconductor substrate 1 corresponding to the isolation region. In addition, the second stacked conductor layer may also be formed only on the portion of the semiconductor substrate corresponding to the P-type region. Alternatively, as shown in FIG. 1 , the second semiconductor stack can also be formed on a portion of the semiconductor substrate 1 corresponding to the isolation region.

Specifically, when both the first semiconductor stack and the second semiconductor stack are formed on the part of the semiconductor substrate corresponding to the isolation region, as shown in FIG. 1, the first semiconductor stack may also be directly formed on the semiconductor substrate. 1 On the part corresponding to the isolation region, the second semiconductor stack is further formed on the part of the first semiconductor stack corresponding to the isolation region. At this time, the N-type region of the semiconductor substrate is the region where the N-type doped semiconductor layer 7 is exposed outside the P-type doped semiconductor layer 12 , and the P-type region of the semiconductor substrate is the region where the P-type doped semiconductor layer 12 is located. Alternatively, the second semiconductor stack may also be directly formed on the portion of the semiconductor substrate corresponding to the isolation region, and the first semiconductor stack may also be formed above the portion of the second semiconductor stack corresponding to the isolation region. At this time, the N-type region of the semiconductor substrate is the region where the N-type doped semiconductor layer is located, and the P-type region of the semiconductor substrate is the region where the P-type doped semiconductor layer is exposed outside the N-type doped semiconductor layer.

Moreover, when both the first semiconductor stack and the second semiconductor stack are formed on the part of the semiconductor substrate corresponding to the isolation region, as shown in FIG. Between the portion of the first semiconductor stack corresponding to the isolation region and the portion of the second semiconductor stack corresponding to the isolation region. Wherein, the material and thickness of the insulating layer 13 can be set according to actual application scenarios. For example, the material of the insulating layer 13 may be insulating materials such as silicon oxide or silicon nitride. The insulating layer 13 may have a thickness of 50 nm to 500 nm.

In the case of adopting the above technical solution, as shown in Figure 1, the carriers of the corresponding conductivity type can respectively pass through the first passivation layer 6 and the second passivation layer 11 through the tunneling effect, and be N-type doped semiconductor Layer 7 or P-type doped semiconductor layer 12 collected. Based on this, when the part of one of the first semiconductor stack and the second semiconductor stack corresponding to the isolation region is located on the other part corresponding to the isolation region, the insulating layer 13 can separate the portion of the first semiconductor stack corresponding to the isolation region. The part is isolated from the part corresponding to the isolation region of the second semiconductor stack to prevent the recombination of carriers at the longitudinal junction between the first semiconductor stack and the second semiconductor stack, and further improve the photoelectric conversion efficiency of the back contact solar cell.

For the above transparent conductive layer, the material and thickness of the transparent conductive layer can be set according to actual application scenarios, and are not specifically limited here. For example, the material of the transparent conductive layer may be fluorine-doped tin oxide, aluminum-doped zinc oxide, tin-doped indium oxide, tungsten-doped indium oxide, molybdenum-doped indium oxide, cerium-doped indium oxide or indium hydroxide. For example: the thickness of the transparent conductive layer may be 10 nm to 1000 nm.

For the above isolation groove, the isolation groove may only penetrate through the part of the transparent conductive layer located on the isolation region. Alternatively, as shown in FIGS. 1 to 4 , the isolation groove 16 may also penetrate through the transparent conductive layer 15 and part of the insulating light-absorbing layer 17 . The width of the isolation groove 16 can be set according to the actual application scene, as long as the part of the transparent conductive layer 15 located on the N-type region can be separated from the part of the transparent conductive layer 15 located on the P-type region through the isolation groove 16 .

For the above-mentioned insulating light-absorbing layer, as shown in Figures 1 to 4, since the insulating light-absorbing layer 17 is at least located at the bottom of the isolation groove 16, and the insulating light-absorbing layer 17 is a non-conductive film layer, the transparent conductive layer 15 is located in the N-type region The upper part and the part of the transparent conductive layer 15 located on the P-type region cannot be conducted through the insulating light-absorbing layer 17, which can prevent the short circuit of the back contact solar cell. At the same time, the insulating light-absorbing layer 17 also has light-absorbing properties. In this case, as shown in FIG. 15 to FIG. 19 , after forming the entire layer of transparent conductive layer 15 covering the second surface, even if a laser etching process is used to form a hole penetrating through the transparent conductive layer 15 on each isolation region. The existence of the isolation groove 16 and the insulating light-absorbing layer 17 can also ensure that the transparent conductive layer 15 is completely cut through, reduce or even eliminate the damage caused by the laser energy to the film layer below the insulating light-absorbing layer 17, and improve the good performance of the back contact solar cell. Rate. At the same time, it can also solve the problems of high manufacturing cost and unsuitability for large-scale mass production caused by the combination of photolithography and wet etching or ink printing and wet etching in the prior art. The manufacturing cost of contact solar cells, and the mass-producibility of improving back contact solar cells.

For example: as shown in Figure 1, in the case where the semiconductor base includes the above-mentioned semiconductor substrate 1, the first semiconductor stack and the second semiconductor stack, because in the high temperature scene, the above-mentioned first passivation layer 6 and the second passivation layer The chemical properties of the passivation layer 11 are prone to change (such as when at least one of the first passivation layer 6 and the second passivation layer 11 is an intrinsic amorphous silicon layer, when adopting a laser etching process to form the isolation groove 16 In some cases, the laser energy will make the part of the intrinsic amorphous silicon layer on or near the isolation region easy to form polysilicon or single crystal silicon, which will affect the interface passivation effect of this part and the selective collection of carriers. ). Based on this, the existence of the insulating light-absorbing layer 17 can reduce or even eliminate laser damage to the first passivation layer 6 and/or the second passivation layer 11 , ensuring excellent working performance of the back contact solar cell.

In the case of the above content, in terms of materials, the material of the insulating light-absorbing layer can be any insulating material with light-absorbing properties. For example, the material of the insulating light-absorbing layer may be ink, photoresist or UV curable glue. In this case, the ink, photoresist and UV curable glue all have good light-absorbing properties, so if the material of the above-mentioned insulating light-absorbing layer is one of the above-mentioned materials, it is possible to form the isolation groove by using a laser etching process. During the process, it is ensured that the insulating light-absorbing material of the insulating light-absorbing layer can be manufactured to reduce or even eliminate the damage caused by the laser to the part of the semiconductor substrate corresponding to the isolation region.

In terms of morphology, the width, thickness and shape of the insulating light-absorbing layer can be set according to actual application scenarios, as long as it can be applied to the back contact solar cell provided by the embodiment of the present invention.

Exemplarily, the width of the insulating light-absorbing layer may be equal to the width of the isolation groove. At this time, the insulating light-absorbing layer is only located at the bottom of the isolation groove. In this case, while ensuring that the light-absorbing material used to manufacture the insulating light-absorbing layer can protect the part of the semiconductor substrate corresponding to the isolation region during the process of forming the isolation groove by the laser etching process, the consumption of the insulating light-absorbing material can also be reduced quantity, reducing the manufacturing cost of the insulating light-absorbing layer.

Alternatively, as shown in FIGS. 1 to 4 , the width of the insulating light-absorbing layer 17 may also be greater than the width of the isolation groove 16 . At this time, the insulating light-absorbing layer 17 is also located between the part of the transparent conductive layer 15 and the part of the semiconductor substrate corresponding to the isolation region. In this case, in the actual manufacturing process, the width of the isolation groove 16 is the etching width of the transparent conductive layer 15 by the laser etching process. Based on this, when the width of the insulating light-absorbing layer 17 is greater than the width of the isolation groove 16 , the width of the insulating light-absorbing layer 17 is also greater than the etching width of the transparent conductive layer 15 by the laser etching process. Moreover, the insulating light-absorbing layer 17 is also located on the part of the transparent conductive layer 15 and the part of the semiconductor substrate corresponding to the isolation region. At this time, the existence of the insulating light-absorbing layer 17 can ensure that the damage caused by laser etching on the bottom of the semiconductor substrate corresponding to the isolation groove 16 and the part near the isolation groove 16 can be reduced or eliminated, and the yield of the back contact solar cell can be further improved.

Wherein, in the back contact solar cell provided by the embodiment of the present invention, the width of the insulating light-absorbing layer is not specifically limited. Exemplarily, the above-mentioned insulating light-absorbing layer may have a width greater than or equal to 5 μm and less than or equal to 5 mm. For example, the width of the insulating light-absorbing layer may be greater than or equal to 5 μm, 100 μm, 300 μm, 600 μm, 900 μm, 2 mm, 4 mm or 5 mm. In this case, as shown in FIGS. 1 to 4 , the width of the insulating light-absorbing layer 17 is greater than or equal to the width of the isolation groove 25 . Based on this, when the width of the insulating light-absorbing layer 17 is within the above range, it is possible to prevent the portion of the transparent conductive layer 15 located on the N-type region due to the smaller width of the insulating light-absorbing layer 17 and the smaller width of the isolation groove 16. It is difficult to separate from the portion of the transparent conductive layer 15 located on the P-type region, suppressing electric leakage. At the same time, it can also prevent the consumption of consumables for the insulating light-absorbing layer 17 due to the large width of the insulating light-absorbing layer 17 , and reduce the manufacturing cost of the insulating light-absorbing material for manufacturing the insulating light-absorbing layer 17 . Moreover, it can also prevent the area of the transparent conductive layer 15 covering the N-type region and the P-type region from being reduced due to the larger width of the insulating light-absorbing layer 17 and the larger width of the isolation groove 16, thereby causing the semiconductor substrate to be in the working state. The carriers generated below cannot be exported by the transparent conductive layer 15 in time, so the width of the insulating light-absorbing layer 17 within the above range can also improve the photoelectric conversion efficiency of the back contact solar cell.

In addition, in an actual application process, along the width direction of the isolation region, the thickness of each part of the insulating light-absorbing layer may be the same or different. The actual thickness of each part of the insulating light-absorbing layer can be determined according to the actual application scenario.

Exemplarily, as shown in FIGS. 2 to 4 , along the width direction of the isolation groove 16 , the thicknesses of the edge regions on both sides of the insulating light-absorbing layer 17 may gradually decrease. At this time, the thicknesses of the edge regions on both sides of the insulating light-absorbing layer 17 may gradually decrease in a linear trend, or gradually decrease in an exponential or parabolic trend. In addition, the degree of gradual reduction in the thickness of the edge regions on both sides of the insulating light-absorbing layer 17 can be set according to actual needs, which is not specifically limited here.

In the case of adopting the above-mentioned technical solution, in the actual manufacturing process, when the isolation groove that runs through the entire layer of the transparent conductive layer covered on the second surface is formed by using the laser etching process, the part of the laser on the transparent conductive layer corresponding to the middle part of the isolation groove The etching strength is higher. Based on this, as shown in FIG. 2 to FIG. 4 and FIG. 12 to FIG. 14 , in the case that the thickness of the edge regions on both sides of the insulating light-absorbing layer 17 gradually decreases along the width direction of the isolation groove 16, it is explained how to manufacture the insulating light-absorbing layer 17. The central region of the insulating light-absorbing material 14 in the layer 17 along the width direction is thicker. Correspondingly, the central region of the insulating light-absorbing material 14 along the width direction has a stronger light-absorbing property, thereby further reducing or even eliminating laser damage to the film layer of the semiconductor substrate at the bottom of the isolation groove 16 . In addition, along the width direction of the isolation groove 16, the thickness of the edge regions on both sides of the insulating light-absorbing layer 17 gradually decreases, which can also reduce the consumption of consumables in the edge regions on both sides of the insulating light-absorbing layer 17, and reduce the manufacturing cost of the insulating light-absorbing layer 17. . At the same time, the surface of the insulating light-absorbing layer 17 facing away from the transparent conductive layer 15 can also be convex, so that the light-absorbing area of the insulating light-absorbing layer 17 facing away from the transparent conductive layer 15 can be increased, thereby reducing the distance between the insulating light-absorbing layer 17 and the transparent conductive layer 17. The unit light absorption on one side of the layer 15 reduces the damage degree of the laser etching process to the insulating light-absorbing material 14 for manufacturing the insulating light-absorbing layer 17, and finally can reduce the manufacturing thickness of the insulating light-absorbing material 14, and further reduce the consumption of the insulating light-absorbing material 14 Consumables.

Certainly, when the thickness of each part of the insulating light-absorbing layer along the width direction of the isolation region is different, the insulating light-absorbing layer may also have a shape that is thick at the edge and thin in the middle. Alternatively, the thickness of the insulating light-absorbing layer may also vary in the form of wavy lines or the like. In the above case, it can also have the above-mentioned beneficial effect when the surface of the insulating light-absorbing layer facing away from the transparent conductive layer is a convex surface.

As a possible implementation manner, as shown in FIG. 4 , the side of the insulating light-absorbing layer 17 in contact with the transparent conductive layer 15 may have at least one light-trapping structure. In this case, the above-mentioned light-trapping structure can be used in the process of forming the isolation groove 16 penetrating the transparent conductive layer 15 through the laser etching process, so that more laser light can be projected into the insulating light-absorbing material for manufacturing the insulating light-absorbing layer 17, preventing The scattering of the laser light affects the morphology of the side wall of the transparent conductive layer 15 corresponding to the isolation groove 16, so as to ensure that the morphology of the two side walls of the transparent conductive layer 15 along the width direction of the isolation groove 16 meets the work requirements, thereby ensuring that the transparent conductive layer 15 Partial regions along the width direction of the isolation groove 16 have good electrical conductivity, which is beneficial to improve the photoelectric conversion efficiency of the back contact solar cell.

Specifically, the above-mentioned light trapping structure may be any structure having a light trapping effect, and the embodiment of the present invention does not specifically limit the shape of the light trapping structure. Exemplarily, as shown in FIG. 4 , the above light trapping structure may be a recessed structure recessed into the insulating light absorbing layer 17 . In this case, in the actual manufacturing process, an insulating light-absorbing material with a light-trapping structure whose shape meets the work requirements can be formed on the isolation region by only using methods such as screen printing or inkjet, and there is no need to form the above-mentioned The light-trapping structure adds additional processing steps, simplifies the manufacturing process of the insulating light-absorbing material for manufacturing the insulating light-absorbing layer 17, and reduces the difficulty of manufacturing the insulating light-absorbing material.

Wherein, the above-mentioned concave structure may be an inverted cone-shaped concave structure, an inverted trapezoidal concave structure, or a hemispherical concave structure, as long as it has a light-trapping effect. Among them, as shown in Figure 4, because the shape of the hemispherical concave structure is relatively regular, there is no need to strictly require the manufacturing process precision in order to form a light-trapping structure with a complex shape, so when the light-trapping structure is a hemispherical concave structure, the insulating light absorption can be further reduced. The difficulty of manufacturing the material. In addition, the hemispherical concave structure is a highly symmetrical concave structure, and the surface morphology of each part of the inwardly concave surface is the same, so that each part of the insulating light-absorbing material has an excellent light-trapping effect, and further ensures transparency. The sidewall morphology of the conductive layer along the width direction meets the working requirements.

In addition, in an actual application process, as shown in FIG. 1 , the back contact solar cell provided by the embodiment of the present invention may further include a first electrode 18 and a second electrode 19 . Wherein, the first electrode 18 is formed on the portion of the transparent conductive layer 15 corresponding to the N-type region. The second electrode 19 is formed on the portion of the transparent conductive layer 15 corresponding to the P-type region. Specifically, the materials of the first electrode 18 and the second electrode 19 may be conductive materials such as copper, silver, aluminum and the like.

Next, as shown in FIG. 1 , a passivation anti-reflection layer 10 is formed on the first surface of the semiconductor substrate. Specifically, the material of the passivation anti-reflection layer 10 may be silicon nitride, silicon oxynitride or silicon oxide. The thickness of the antireflection layer may be 50nm to 200nm. Of course, the thickness of the passivation anti-reflection layer 10 can also be set to other appropriate values according to different application scenarios.

In a second aspect, an embodiment of the present invention further provides a photovoltaic module, which includes the back contact solar cell provided in the above first aspect and various implementations thereof.

For the beneficial effects of the second aspect in the embodiments of the present invention, reference may be made to the analysis of the beneficial effects in the first aspect and its various implementation manners, and details are not described here.

In a third aspect, the embodiment of the present invention also provides a method for manufacturing a back contact solar cell. Hereinafter, the manufacturing process will be described based on the operation sectional views shown in FIGS. 2 to 20 . Specifically, the manufacturing method of the back contact solar cell comprises the following steps:

First, as shown in FIG. 10, a semiconductor substrate is formed. The semiconductor substrate has opposing first and second sides. The second surface has N-type regions and P-type regions distributed alternately at intervals, and an isolation region between each N-type region and the corresponding P-type region.

Specifically, information such as the specific structure and materials of the above-mentioned semiconductor substrate can be referred to above, and will not be repeated here. In addition, it can be understood that when the structures of the semiconductor substrates are different, the corresponding manufacturing processes of the semiconductor substrates are also different.

Exemplarily, as shown in FIG. 1 , when the semiconductor base includes the above-mentioned semiconductor substrate 1 , the first semiconductor stack and the second semiconductor stack, the manufacturing process of the semiconductor base may include steps: first, a semiconductor substrate is provided. For the material of the semiconductor substrate, reference may be made to the foregoing. Next, processes such as deposition and etching may be used to form a first semiconductor stack at least on a portion of the semiconductor substrate corresponding to the N-type region. Wherein, along the direction away from the semiconductor substrate, the first semiconductor stack includes a first passivation layer and an N-type doped semiconductor layer on the first passivation layer. Next, processes such as deposition and etching may be used to form a second semiconductor stack at least on a portion of the semiconductor substrate corresponding to the P-type region. Wherein, along the direction away from the semiconductor substrate, the second semiconductor stack includes a second passivation layer and a P-type doped semiconductor layer on the second passivation layer.

It should be noted that, the back contact solar cell provided in the embodiment of the present invention does not specifically limit the manufacturing sequence of the first semiconductor stack and the second semiconductor stack. The specific formation sequence of the two can be determined according to the structure of the back contact solar cell and the actual application scenario.

In addition, when the first semiconductor stack is also formed on the part of the semiconductor substrate corresponding to the isolation region, the second semiconductor stack is also formed above the part of the first semiconductor stack corresponding to the isolation region; or, the second semiconductor stack is also formed Formed on the part of the semiconductor substrate corresponding to the isolation region, and the first semiconductor stack is also formed above the part of the second semiconductor stack corresponding to the isolation region, at least in the part of the semiconductor substrate corresponding to the N-type region Between forming the first semiconductor stack on the above-mentioned second semiconductor stack at least on the part corresponding to the P-type region of the semiconductor substrate, the manufacturing method of the back contact solar cell further includes: An insulating layer is formed between the portion and the portion of the second semiconductor stack corresponding to the isolation region.

The process of manufacturing the back contact solar cell will be described in detail below by taking the second semiconductor stack is also formed on the part of the first semiconductor stack corresponding to the isolation region, and the back contact solar cell also includes an insulating layer as an example:

As shown in FIG. 5, a process such as plasma-enhanced chemical vapor deposition can be used to sequentially form a stacked first passivation material layer 2, an N-type doped material layer, and an N-type doped layer on the backlight surface of the semiconductor substrate 1 along the thickness direction of the semiconductor substrate. Semiconductor material layer 3, insulating material layer 4 and mask material layer. Next, as shown in FIG. 6, the mask material layer can be patterned by laser etching and other processes, and only the part of the mask material layer covering the corresponding N-type region of the semiconductor substrate 1 is reserved, so that the mask material layer The remaining part forms the mask layer 5; and under the masking effect of the mask layer, the insulating material layer, the N-type doped semiconductor material layer and the first passivation material layer are patterned by using processes such as wet etching , removing at least the parts of the above-mentioned three film layers located on the corresponding P-type region of the semiconductor substrate, so that the remaining part of the N-type doped semiconductor material layer forms an N-type doped semiconductor layer, and the remaining part of the first passivation material layer A first passivation layer is formed. Then, as shown in FIG. 7, the mask layer is removed. Next, as shown in FIG. 8, the second passivation material layer 8 covering the backlight surface and the P-type doped semiconductor layer 8 can be sequentially formed along the direction away from the semiconductor substrate 1 by using processes such as plasma enhanced chemical vapor deposition. material layer 9; and forming a passivation anti-reflection layer 10 on the light-facing surface of the semiconductor substrate 1. Wherein, the formation order of the above-mentioned second passivation material layer 8 , P-type doped semiconductor material layer 9 , and passivation anti-reflection layer 10 can be determined according to actual application scenarios, and is not specifically limited here. Then, as shown in FIG. 10 , the second passivation material layer and the part of the P-type doped semiconductor material layer located on the N-type region can be selectively removed by means of photolithography combined with wet etching, so that the second passivation layer The remaining part of the passivation material layer forms the second passivation layer 11 , and the remaining part of the P-type doped semiconductor material layer forms the P-type doped semiconductor layer 12 . As shown in FIG. 10, under the mask effect of the P-type doped semiconductor layer 12 and the second passivation layer 11, wet etching and other processes are used to remove the exposed part of the insulating material layer, so that the insulating material layer The remaining part forms an insulating layer 13 to obtain a semiconductor substrate.

It should also be noted that the above-mentioned semiconductor substrate can be formed in various ways. How to form the above-mentioned semiconductor substrate is not the main feature of the present invention, so in this specification, it is only briefly introduced so that those skilled in the art can easily implement the present invention. Those of ordinary skill in the art can completely imagine other ways to manufacture the above-mentioned semiconductor substrate.

Next, as shown in FIGS. 11 to 14 , an insulating light-absorbing material 14 is formed on at least part of the isolation region.

In an actual manufacturing process, a photolithography process, a screen printing process, or an inkjet printing process can be used to form an insulating light-absorbing material. Among them, since the screen printing process and the inkjet printing process are conventional processes for manufacturing back-contact solar cells, when the insulating light-absorbing material is formed by the screen printing process or the ink-jet printing process, it is not necessary to use a separate manufacturing method to form the insulating light-absorbing material. device of. In other words, the manufacturing method of the back contact solar cell provided by the embodiment of the present invention is compatible with the conventional manufacturing process and equipment of the conventional back contact solar cell, reduces the manufacturing difficulty of the back contact solar cell, and improves the manufacturing efficiency.

In addition, after the above-mentioned insulating light-absorbing material is processed by a subsequent laser etching process, the above-mentioned insulating light-absorbing layer will be formed. Based on this, the corresponding characteristics of the insulating light-absorbing material can be determined with reference to the material and width of the insulating light-absorbing layer mentioned above, and will not be repeated here.

Specifically, as shown in FIG. 11 , the top surface area of the part of the insulating light-absorbing material 14 corresponding to the isolation groove may be equal to the bottom surface area of the part of the insulating light-absorbing material 14 corresponding to the isolation groove. At this time, both the top surface and the bottom surface of the insulating light-absorbing material 14 are planes parallel to the backlight surface of the semiconductor substrate 1 . Alternatively, as shown in FIG. 12 to FIG. 14 , the top surface area of the portion of the insulating light-absorbing material 14 corresponding to the isolation groove may be greater than the bottom surface area of the portion of the insulating light-absorbing material 14 corresponding to the isolation groove. In this case, the specific surface area of the top surface of the insulating light-absorbing material 14 is large, which can reduce the unit light absorption of the insulating light-absorbing material 14 on the side away from the transparent conductive layer, and reduce the impact of the subsequent laser etching process on the insulating light-absorbing material for manufacturing the insulating light-absorbing layer. 14, the manufacturing thickness of the insulating light-absorbing material 14 can be reduced in the end, and the consumption of the insulating light-absorbing material 14 can be further reduced.

In addition, along the width direction of the isolation region, the insulating light-absorbing material may be thick on both sides and thin in the middle. At this time, along the width direction of the isolation region, the average thickness of the edge regions on both sides of the insulating light-absorbing material is greater than the average thickness of its middle region. Alternatively, as shown in FIGS. 12 to 14 , the insulating light-absorbing material 14 may also be thick in the middle and thin on both sides. At this time, along the width direction of the isolation groove, the average thickness of the middle region of the insulating light-absorbing material 14 is greater than the average thickness of the edge regions on both sides of the insulating light-absorbing material 14 .

Wherein, the specific thickness of the insulating light-absorbing material can be determined according to actual application scenarios, and is not specifically limited here. Exemplarily, exemplary, the minimum thickness of the part of the insulating light-absorbing material corresponding to the isolation groove is greater than or equal to 0.05 μm and less than or equal to 100 μm. For example: the minimum thickness of the part of the insulating light-absorbing material corresponding to the isolation groove is 0.05 μm, 10 μm, 30 μm, 60 μm, 90 μm or 100 μm, etc. In this case, the minimum thickness of the part of the above-mentioned insulating light-absorbing material corresponding to the isolation groove is within the above-mentioned range, which can prevent the part of the insulating light-absorbing material corresponding to the isolation groove from being cut before the transparent conductive layer is completely carved due to the small minimum thickness. All are etched away by the laser to ensure that the insulating light-absorbing material can protect the part of the semiconductor substrate corresponding to the isolation region during the entire etching process, and further ensure that the back contact solar cell has a higher yield. At the same time, it can also prevent the use of consumables of the insulating light-absorbing material from being large due to the above-mentioned large minimum thickness, which is beneficial to reducing the manufacturing cost of the insulating light-absorbing material.

Secondly, in an actual application process, as shown in FIG. 14 , the side of the insulating light-absorbing material 14 facing away from the semiconductor substrate may be provided with multiple light-trapping structures. For the specific shape of the light-trapping structure, reference may be made to the shape of the light-trapping structure disposed on the insulating light-absorbing layer described above, and will not be repeated here.

Wherein, the above-mentioned multiple light trapping structures may be randomly arranged on the side of the insulating material away from the semiconductor substrate. Preferably, as shown in FIG. 14 , a plurality of light-trapping structures are evenly distributed on the side of the insulating light-absorbing material 14 away from the semiconductor substrate. In this case, the light trapping effect of each part of the insulating light-absorbing material 14 is approximately the same, thereby ensuring that the area of the semiconductor substrate covered by each part of the insulating light-absorbing material 14 can be effectively protected, and further improving the yield of the back contact solar cell.

Next, after the above-mentioned insulating light-absorbing material is formed, as shown in FIGS. 15 to 18 , a process such as physical vapor deposition can be used to form a transparent conductive layer 15 covering the N-type region, the P-type region and the insulating light-absorbing material 14. . Specifically, information such as the material and thickness of the transparent conductive layer 15 can refer to the foregoing.

Then, as shown in FIG. 19 , using a laser etching process, an isolation groove 16 penetrating through the transparent conductive layer 15 is formed on each isolation region, and the remaining insulating light-absorbing material forms an insulating light-absorbing layer 17 . The isolation groove 16 is used to isolate the part of the transparent conductive layer 15 located on the N-type region from the part of the transparent conductive layer 15 located on the P-type region. The insulating light-absorbing layer 17 is at least located at the bottom of the isolation groove 16 , and the width of the insulating light-absorbing layer 17 is greater than or equal to the width of the isolation groove 16 .

Specifically, the working parameters of the laser etching process may be determined according to actual application scenarios, and are not specifically limited here.

As shown in Figure 20, the first electrode 18 can be formed on the part of the transparent conductive layer 15 corresponding to the N-type region, and the second electrode can be formed on the part of the transparent conductive layer 15 corresponding to the P-type region by means of screen printing or electroplating. 19. Wherein, the materials of the first electrode 18 and the second electrode 19 can refer to the above, and will not be repeated here.

For the beneficial effects of the third aspect and its various implementations in the embodiments of the present invention, reference may be made to the analysis of the beneficial effects of the first aspect and its various implementations, and details are not described here.

In the above description, technical details such as patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design a method that is not exactly the same as the method described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be advantageously used in combination.

The embodiments of the present disclosure have been described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the present disclosure, and these substitutions and modifications should all fall within the scope of the present disclosure.

Claims (18)

1. A back contact solar cell, comprising:

a semiconductor substrate having opposite first and second sides; the second surface is provided with N-type regions and P-type regions which are alternately distributed at intervals, and isolation regions positioned between each N-type region and the corresponding P-type region;

a transparent conductive layer covering the second face; each isolation region is provided with an isolation groove penetrating through the transparent conductive layer, and the isolation groove is used for isolating the part of the transparent conductive layer on the N-type region from the part of the transparent conductive layer on the P-type region;

the insulating light absorption layer is at least positioned at the bottom of the isolation groove, and the width of the insulating light absorption layer is larger than or equal to the width of the isolation groove.

2. The back contact solar cell of claim 1, wherein the width of the insulating light absorbing layer is greater than the width of the isolation trench;

the insulating light absorption layer is also positioned between a part of the transparent conductive layer and a part of the semiconductor substrate corresponding to the isolation region.

3. The back contact solar cell according to claim 2, wherein the thickness of both side edge regions of the insulating light absorbing layer is gradually reduced in the width direction of the isolation trench.

4. The back contact solar cell of claim 2, wherein a side of the insulating light absorbing layer in contact with the transparent conductive layer has at least one light trapping structure.

5. The back contact solar cell of claim 4, wherein the light trapping structure is a recessed structure recessed into the insulating light absorbing layer.

6. The back contact solar cell of claim 5, wherein the recessed structures are hemispherical recessed structures.

7. The back contact solar cell according to claim 1, wherein the width of the insulating light absorbing layer is 5 μm or more and 5mm or less; and/or the number of the groups of groups,

The material of the insulating light absorption layer is ink, photoresist or UV curing adhesive.

8. The back contact solar cell of any one of claims 1-6, wherein the semiconductor substrate comprises: a semiconductor substrate having a semiconductor layer formed thereon,

a first semiconductor stack formed at least on a portion of the semiconductor substrate corresponding to the N-type region; the first semiconductor lamination comprises a first passivation layer and an N-type doped semiconductor layer positioned on the first passivation layer along the direction away from the semiconductor substrate;

a second semiconductor stack formed at least on a portion of the semiconductor substrate corresponding to the P-type region; the second semiconductor stack includes a second passivation layer and a P-type doped semiconductor layer on the second passivation layer in a direction away from the semiconductor substrate.

9. The back contact solar cell of claim 8, wherein the first semiconductor stack is further formed on a portion of the semiconductor substrate corresponding to the isolation region, the second semiconductor stack is further formed over a portion of the first semiconductor stack corresponding to the isolation region; or, the second semiconductor lamination is further formed on a part of the semiconductor substrate corresponding to the isolation region, and the first semiconductor lamination is further formed above a part of the second semiconductor lamination corresponding to the isolation region;

The semiconductor substrate further includes an insulating layer between a portion of the first semiconductor stack corresponding to the isolation region and a portion of the second semiconductor stack corresponding to the isolation region.

10. A photovoltaic module comprising a back contact solar cell according to any one of claims 1 to 9.

11. A method of manufacturing a back contact solar cell, comprising:

forming a semiconductor substrate; the semiconductor substrate has opposite first and second sides; the second surface is provided with N-type regions and P-type regions which are alternately distributed at intervals, and isolation regions positioned between each N-type region and the corresponding P-type region;

forming an insulating light absorbing material over at least a portion of the isolation region;

forming a transparent conductive layer which covers the N-type region, the P-type region and the insulating light absorption material;

forming an isolation groove penetrating through the transparent conductive layer on each isolation area by adopting a laser etching process, and enabling the rest insulating light absorption material to form an insulating light absorption layer; the isolation groove is used for isolating the part of the transparent conducting layer on the N-type region from the part of the transparent conducting layer on the P-type region; the insulating light absorption layer is at least positioned at the bottom of the isolation groove, and the width of the insulating light absorption layer is greater than or equal to the width of the isolation groove.

12. The method of claim 11, wherein a top surface area of the portion of the insulating light absorbing material corresponding to the isolation trench is greater than a bottom surface area of the portion of the insulating light absorbing material corresponding to the isolation trench.

13. The method of manufacturing a back contact solar cell according to claim 11 or 12, wherein an average thickness of the middle region of the insulating light absorbing material is greater than an average thickness of both side edge regions of the insulating light absorbing material in a width direction of the isolation trench.

14. The method of claim 11, wherein a side of the insulating light absorbing material facing away from the semiconductor substrate is provided with a plurality of light trapping structures.

15. The method of claim 14, wherein the plurality of light trapping structures are uniformly distributed on a side of the insulating light absorbing material facing away from the semiconductor substrate.

16. The method of claim 11, wherein the insulating light absorbing material is formed using a screen printing process or an inkjet printing process; and/or the number of the groups of groups,

The minimum thickness of the part of the insulating light absorbing material corresponding to the isolation groove is more than or equal to 0.05 mu m and less than or equal to 100 mu m.

17. The method of claim 11, wherein forming a semiconductor substrate comprises:

providing a semiconductor substrate;

forming a first semiconductor lamination at least on a part of the semiconductor substrate corresponding to the N-type region; the first semiconductor lamination comprises a first passivation layer and an N-type doped semiconductor layer positioned on the first passivation layer along the direction away from the semiconductor substrate;

forming a second semiconductor lamination layer at least on a part of the semiconductor substrate corresponding to the P-type region; the second semiconductor lamination comprises a second passivation layer and a P-type doped semiconductor layer positioned on the second passivation layer along the direction away from the semiconductor substrate; the semiconductor base includes the semiconductor substrate, the first semiconductor stack, and the second semiconductor stack.

18. The method of claim 17, wherein the first semiconductor stack is further formed on a portion of the semiconductor substrate corresponding to the isolation region, and the second semiconductor stack is further formed over a portion of the first semiconductor stack corresponding to the isolation region; or, the second semiconductor lamination is further formed on a part of the semiconductor substrate corresponding to the isolation region, and the first semiconductor lamination is further formed above a part of the second semiconductor lamination corresponding to the isolation region;

The method for manufacturing the back contact solar cell further comprises the steps of:

an insulating layer is formed between a portion of the first semiconductor stack corresponding to the isolation region and a portion of the second semiconductor stack corresponding to the isolation region.

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