Back contact battery and preparation method thereof and back contact battery pack

Abstract

The present application provides a back-contact cell, a method for preparing the same, and a back-contact cell group. The back-contact cell includes: a silicon substrate, the silicon substrate includes a substrate front side close to sunlight and a substrate back side away from sunlight; a first doping region, an isolation region, and a second doping region, located on the back side of the substrate, wherein the first doping region and the second doping region have different doping elements, and the isolation region is located between the first doping region and the second doping region on the back side of the substrate; a front passivation anti-reflection layer, located on the front side of the substrate; and a protective layer, located on at least part of the front passivation anti-reflection layer, wherein the protective layer includes a resin material. The back-contact cell, the method for preparing the same, and the back-contact cell group of the present application can eliminate the isolation paper between cells, reduce the production cost, and improve the production yield of photovoltaic cells.

Description

Technical Field

[0001] The present application mainly relates to the field of photovoltaic technology, and in particular to a back-contact cell and a preparation method thereof, as well as a back-contact cell group. Background Art

[0002] The all-back-contact photovoltaic cell (IBC, Interdigitated back contact) has both a P region and an N region on the back side of the cell. In this design, electron-hole pairs are generated in the high-life body region and collected in the N and P regions on the back of the cell. The metal on the back side of the cell connects the P and N regions through P-type metal contacts and N-type metal contacts, respectively, and there is no metal pattern on the front side, thus avoiding light blocking and improving light absorption. The cell types derived on this basis have relatively better effects. For example, the TBC cell, which is a combination of TOPCon (Tunnel Oxide Passivated Contact) cells and IBC cells, has higher efficiency than traditional TOPCon cells.

[0003] For conventional double-sided metallized cells, the height of the metal electrode is higher than the surface of the passivation film, so the cells can be stacked directly without rubbing against the passivation film and causing problems such as poor EL of the cells. However, since there is no grid line on the front side of the full back contact cell (IBC) to protect the front passivation film, the cells cannot be stacked directly. The existing method requires placing isolation paper directly between the two cells to protect the front velvet surface. However, isolation paper not only increases manufacturing costs, but also easily causes problems such as scratches on the cell and equipment failure during transportation. Summary of the invention

[0004] The technical problem to be solved by the present application is to provide a back-contact battery and a preparation method thereof, as well as a back-contact battery pack, which can save the isolation paper between batteries, reduce the production cost, and improve the yield rate of photovoltaic cell preparation.

[0005] To solve the above technical problems, the present application provides a back-contact battery, comprising: a silicon substrate, the silicon substrate comprising a substrate front side close to sunlight and a substrate back side away from the sunlight; a first doped region, an isolation region, and a second doped region, located on the back side of the substrate, wherein the first doped region and the second doped region have different doping elements, and the isolation region is located between the first doped region and the second doped region on the back side of the substrate; a front passivation anti-reflection layer, located on the front side of the substrate; and a protective layer, located on at least part of the front passivation anti-reflection layer, wherein the protective layer comprises a resin material.

[0006] Optionally, the back contact battery further includes a battery edge and an edge protection zone, the protective layer is located in the edge protection zone, and the outer side of the edge protection zone closer to the battery edge is between 0.1 mm and 10 mm away from the battery edge.

[0007] Optionally, the width of the edge protection area is 0.005 mm to 10 mm.

[0008] Optionally, the protective layer is a pyramid velvet surface.

[0009] Optionally, the protective layer is formed by roller embossing, wherein the surface of the roller has pyramid-shaped protrusions.

[0010] Optionally, the protective layer is formed by attaching a protective agent on at least a portion of the front passivation anti-reflection layer, performing a first curing, using roller embossing, and performing a second curing, wherein a first curing time of the first curing is shorter than a second curing time of the second curing.

[0011] Optionally, the irradiation energy of the first curing and / or the second curing is 1300 mj / cm 2 ~1700mj / cm 2 .

[0012] Optionally, the protective layer is formed by spraying a protective agent, wherein the spray printing includes spraying the protective agent in the shape of ink drops on at least a portion of the front passivation anti-reflection layer to form a protective layer having the pyramid velvet surface on the front passivation anti-reflection layer.

[0013] Optionally, the protective layer is formed by screen printing a protective agent, wherein the screen printing screen mold has a pyramid shape, and the screen printing includes printing the protective agent through the screen mold on at least a portion of the front passivation anti-reflection layer to form a protective layer having the pyramid velvet surface on the front passivation anti-reflection layer.

[0014] Optionally, the silicon substrate is an N-type substrate or a P-type substrate.

[0015] Optionally, the front side of the substrate is a velvet surface, and the side of the front passivation anti-reflection layer away from the front side of the substrate is also the velvet surface.

[0016] Optionally, the front passivation anti-reflection layer includes aluminum oxide, silicon nitride and / or silicon oxynitride.

[0017] Optionally, the back-contact cell further includes a back passivation anti-reflection layer located on a side of the first doped region, the isolation region and the second doped region away from the back side of the substrate, and the back passivation anti-reflection layer includes aluminum oxide and / or silicon nitride.

[0018] Optionally, the back-contact cell further includes a first electrode and a second electrode, which pass through the back passivation anti-reflection layer on one side of the back side of the substrate and are in contact with the first doped region and the second doped region respectively.

[0019] Optionally, the protective layer covers 1% to 50% of the front surface of the substrate.

[0020] Optionally, the protective layer is in a continuous or discontinuous straight line shape, or an irregular shape on the front side of the substrate of the back contact battery.

[0021] Optionally, a thickness of the protection layer along a first direction perpendicular to the silicon substrate is 6 microns to 15 microns.

[0022] Optionally, the protective layer has a transmittance greater than 80% for incident light in the wavelength range of 300 nm to 1200 nm.

[0023] Optionally, the refractive index of the protective layer is less than 1.6.

[0024] Optionally, the resin material includes epoxy resin or acrylic resin.

[0025] In order to achieve the above-mentioned purpose, another aspect of the present application further proposes a method for preparing a back-contact battery, comprising the following steps: preparing a silicon substrate, the silicon substrate comprising a substrate front side close to sunlight and a substrate back side away from the sunlight; preparing a first doping region, an isolation region, and a second doping region on the back side of the substrate, wherein the first doping region and the second doping region have different doping elements, and the isolation region is located between the first doping region and the second doping region on the back side of the substrate; preparing a front passivation anti-reflection layer on the front side of the substrate; and preparing a protective layer on at least part of the front passivation anti-reflection layer, the protective layer comprising a resin material.

[0026] Optionally, the back contact battery has a battery edge, and the step of preparing the protective layer includes preparing the protective layer with a metal velvet surface in an edge protection zone, wherein the outer side of the edge protection zone closer to the battery edge is between 0.1 mm and 10 mm away from the battery edge.

[0027] Optionally, the step of preparing the protective layer includes preparing a protective layer having a pyramid velvet surface.

[0028] Optionally, the step of preparing the protective layer includes: spraying a protective agent on at least a portion of the front passivation anti-reflection layer and performing a first curing; embossing the protective agent with a roller having pyramid-shaped protrusions so that the protective agent presents a pyramid morphology; and performing a second curing.

[0029] Optionally, the time of the first curing is 2s to 4s, and / or the time of the second curing is 4s to 8s, and / or the irradiation energy range of the first curing and the second curing is 1300mj / cm 2 ~1700mj / cm 2 .

[0030] Optionally, the step of preparing the protective layer includes: spraying a protective agent on at least a portion of the front passivation anti-reflection layer, while controlling the protective agent to be in the shape of ink drops so that the protective agent presents a pyramid morphology when attached to the front passivation anti-reflection layer; and performing photocuring.

[0031] Optionally, the step of preparing the protective layer includes: preparing a screen mold with pyramid protrusions; printing a protective agent on at least a portion of the front passivation anti-reflection layer through the screen mold so that the protective agent presents a pyramid morphology when attached to the front passivation anti-reflection layer; and performing photocuring.

[0032] Optionally, the preparation method also includes: polishing the silicon substrate when preparing the silicon substrate; preparing the first doped region by LPCVD and boron diffusion; removing the borosilicate glass in a local area on the back side of the substrate by laser; cleaning and removing the first doped region in the local area on the back side of the substrate, and performing phosphorus diffusion to prepare a second doped region; cleaning and removing the borosilicate glass and / or phosphorus silicon glass on the front side and / or the side side of the substrate, and performing texturing on one side of the front side of the substrate; preparing double-sided aluminum oxide and a front passivation anti-reflection layer on the front side of the substrate; preparing a first electrode and a second electrode on the back side of the substrate; and preparing the protective layer on at least a portion of the front passivation anti-reflection layer.

[0033] Another aspect of the present application also proposes a back-contact battery pack, including a plurality of back-contact batteries proposed in any embodiment of the present application stacked on each other, or a plurality of back-contact batteries stacked on each other and made according to the preparation method proposed in any embodiment of the present application.

[0034] Compared with the prior art, the present application has the following advantages: the back-contact battery proposed in the present application, by providing a protective layer comprising a resin material on the anti-reflection layer on the front section of the front side of the battery, not only protects the back-contact battery itself, but also eliminates the need for additional isolation paper when multiple back-contact batteries are in contact or stacked, which can reduce costs and improve yields in the manufacturing process and subsequent processing and application processes of the back-contact battery. On this basis, in some preferred embodiments, the protective layer has a pyramid velvet surface, so that the reflection of incident light by the protective layer can be further reduced for the back-contact battery itself. On the other hand, in some preferred embodiments, the protective layer is provided at the edge of the battery cell, which more effectively protects the edge of the battery, avoids scratches on the functional layers (such as the passivation layer) inside the battery caused by scratches on the edge of the battery, and further improves the yield of battery generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0036] Figure 1 is a schematic structural diagram of a back contact battery according to an embodiment of the present application;

[0037] Figure 2~Figure 3 is a schematic diagram of the arrangement position of a protective layer in a back contact battery in different embodiments of the present application;

[0038] Figure 4 , Figure 5 and Figure 6 They are schematic diagrams of the arrangement positions of the protective layer in a back contact battery in different embodiments of the present application;

[0039] Figure 7 is a schematic diagram of the principle of enhancing the reflection effect of a protective layer in a back contact cell according to an embodiment of the present application; and

[0040] Figure 8 and Fig. 9 It is a schematic flow chart of a method for preparing a back-contact battery according to different embodiments of the present application. DETAILED DESCRIPTION

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0042] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0043] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0044] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0045] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0046] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0047] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0048] An embodiment of the present application refers to Figure 1A back contact cell 10 is proposed, comprising a silicon substrate 11, a first doping region 12, an isolation region 13, a second doping region 14, a front passivation anti-reflection layer 15, and a protective layer 16. Specifically, the silicon substrate 11 comprises a substrate front side 111 close to sunlight S and a substrate back side 112 away from sunlight. The first doping region 12, the isolation region 13, and the second doping region 14 are located on the substrate back side 112, wherein the first doping region 12 and the second doping region 14 have different doping elements, and the isolation region 13 is located between the first doping region 12 and the second doping region 14 on the substrate back side 112. The front passivation anti-reflection layer 15 is located on the substrate front side 111. The protective layer 16 is located on at least part of the front passivation anti-reflection layer 15. In the present application, the protective layer 16 comprises a resin material. Preferably, the resin material may be an epoxy resin or an acrylic resin.

[0049] For example, in different embodiments of the present application, the silicon substrate 11 may be an N-type substrate doped with phosphorus or a P-type substrate doped with boron. Figure 1 In the embodiment shown, preferably, the front surface 111 of the substrate is a velvet surface, and the side of the front passivation anti-reflection layer 15 away from the front surface 111 of the substrate also presents a velvet surface morphology. In the embodiment, one side of the back surface 112 of the substrate of the back contact cell 10 is specifically implemented as a polished surface, but the present application is not limited thereto.

[0050] exist Figure 1 In the embodiment shown, the front passivation anti-reflection layer 15 exemplarily comprises aluminum oxide, silicon nitride and / or silicon oxynitride. Further preferably, in this embodiment, the back contact cell 10 further comprises a back passivation anti-reflection layer 17, which is located on the side of the first doping region 12, the isolation region 13 and the second doping region 14 away from the back side 112 of the substrate, and the back passivation anti-reflection layer 17 comprises aluminum oxide and / or silicon nitride. Figure 1 It is also shown that the back contact cell 10 includes a first electrode 181 and a second electrode 182 , which pass through the back passivation anti-reflection layer 17 on one side of the back side 112 of the substrate and contact the first doping region 12 and the second doping region 14 respectively.

[0051] In this embodiment, by providing the protective layer 16, when the back contact cells 10 need to be stacked with each other in various situations such as during the preparation process or even in the subsequent component formation process, there is no need to provide additional isolation paper between adjacent cells to avoid the velvet structure of the back contact cell 10 facing the sunlight S from being damaged, thereby reducing costs and improving yield. Preferably, for the entire back contact cell 10, the protective layer 16 covers 1% to 50% of the front side 111 of the substrate. Such a setting can protect the back contact cell 10 while minimizing the shielding of the sunlight S, thereby reducing the impact on the cell efficiency. Therefore, within the range of 1% to 50%, it is preferably set to a coverage ratio of 8% to 15%, or more preferably, a range of 10% or 9% to 11%.

[0052] Further preferably, in order to take into account the role of the protective layer 16 and to avoid blocking the sunlight S as much as possible, the protective layer 16 can also be preferably selected for other characteristics such as size. Exemplarily, the protective layer 16 can be set to a thickness of less than 100 microns along the first direction Z perpendicular to the silicon substrate 11, preferably in the range of 10 microns or about 10 microns, for example, it is preferably set to 6 microns to 15 microns. Further preferably, when selecting and setting the material of the protective layer 16, it can be controlled to have a transmittance of more than 80% for the incident light in the 300 nanometer to 1200 nanometer band. On this basis, on the other hand, the refractive index of the protective layer 16 is less than 1.6, preferably within the range of 1.2 to 1.6. It should be noted that the present application does not make necessary restrictions on the thickness, material, etc. of the protective layer 16. In different implementation situations, the relationship between transmittance, refractive index or thickness can be comprehensively considered. For example, when the protective layer 16 adopts a material with a higher transmittance, the thickness of the protective layer 16 can be appropriately increased, thereby playing a better protective role. For the back contact battery 10, according to actual production conditions, it is considered that the protective layer 16 is set to have a thickness of 6 microns to 15 microns along the first direction Z perpendicular to the silicon substrate 11, and the transmittance of the incident light in the band of 300 nanometers to 1200 nanometers is greater than 80% and / or the refractive index is within the range of 1.2 to 1.6 as a more preferred characteristic selection.

[0053] It is understandable that, since the protective layer 16 is used to protect the back contact battery 10, the present application does not limit the specific position of the protective layer 16 on the back contact battery 10 and the final arrangement thereof. For example, on the side of the front surface 111 of the substrate, the protective layer 16 may be in a continuous or discontinuous straight line shape, or an irregular shape (such as a dot shape). In addition, the protective layer 16 does not necessarily need to correspond to the position of the first electrodes 181 and 182 on the side of the back surface 112 of the substrate, etc. ( Figure 1Only an indication of the location is provided). For example, Figure 2 and Figure 3 Shown based on Figure 1 Two different implementations of the embodiment respectively show a back contact battery 101 and a back contact battery 102, wherein the back contact battery 101 and the back contact battery 102 are the same in structure except for the different arrangement of the protective layer. Figure 1 The back contact cell 10 shown is identical. Figure 2 , the protective layer 161 in the back contact battery 101 is arranged in three continuous straight lines, and according to Figure 3 , the protective layer 162 of the back contact battery 102 is arranged in a continuous straight line shape taking into account both the edge area and the middle area. It should be noted that, Figure 2 and Figure 3 Only some arrangements of the protective layer are shown as examples, but the present application is not limited thereto. Among these arrangements, it can be considered that there are some preferred options, such as referring to Figure 2 The protective layer 161 is set to a structure that is roughly centrally symmetrical with respect to the entire back contact battery 101, and those skilled in the art can make specific selections and settings based on actual conditions.

[0054] On this basis, this application also combines Figure 4~Figure 6 A preferred embodiment is proposed, wherein: Figure 4 and Figure 5 Two preferred implementations of the protective layer are proposed (protective layer 163 and protective layer 164). Figure 6 Shown as Figure 4 The protective layer 163 is formed on the back contact battery 104. Figure 6 In such a preferred embodiment, the back contact battery 104 includes a battery edge 1040 and an edge protection zone 160, the protective layer 163 is located in the edge protection zone 160, and the distance w1 between the outer side of the edge protection zone 160 closer to the battery edge 1040 and the battery edge 1040 is in the range of 0.1 mm to 10 mm.

[0055] It is understandable that for the sake of simplicity of the drawings, Figure 6 A portion of the edge protection zone 160 is shown by a dashed line. Figure 6 All the intermittently arranged protective layers 163 shown are connected as a whole in the manner of extension indicated by the dotted lines to form a complete edge protection zone 160. Further preferably, the value of the width w2 of the edge protection zone 160 can be set to 0.005 mm to 10 mm. Figure 4 and Figure 5 , Figure 4 Shows Figure 6 In the embodiment, the overall morphology of the protective layer 163 disposed along the complete battery edge 1040 is a discontinuous structure similar to a rectangle. In contrast, Figure 5 The protective layer 164 is shown, and the discontinuous structure is adjusted to a continuous structure based on the protective layer 163. Similar to the above description, even if the protective layer is set near the edge of the battery to implement the preferred embodiment, the present application does not limit the specific implementation of the protective layer as continuous, discontinuous or regular pattern, special shape, etc.

[0056] In such Figure 1 In the embodiment shown, since a protective layer 16 is provided on the front passivation anti-reflection layer 15 of the back contact cell 10, the absorption probability of the incident light can be increased. Figure 7 , Figure 7 The left side portion is the area on the surface of the back contact battery 10 where the protective layer 16 is not provided. Figure 7 The right part shows the area where the protective layer 16 is provided on the surface of the back contact cell 10. It can be seen that after the protective layer 16 is provided on the front passivation anti-reflection layer 15, some of the sunlight S that passes through the first path and then directly reflects through the second path generates a third path through the refraction of the protective layer 16 and is retained in the back contact cell 10.

[0057] On this basis, it is more preferred that, for example, Figure 1 In the illustrated embodiment, part or all of the protective layer 16 can also be set as a pyramid velvet surface, thereby further enhancing the anti-reflection effect of the side of the back contact cell 10 facing the sunlight S. In the present application, the protective layer 16 with the pyramid velvet surface can be prepared by a variety of processes, and the preferred case is understood below. In the first case, the protective layer 16 can be formed by roller embossing, wherein the surface of the roller has a pyramid-shaped protrusion. Specifically, the protective layer 16 is formed by attaching a protective agent to at least part of the front passivation anti-reflection layer 15, curing it for the first time, using roller embossing, and curing it for the second time, wherein the first curing time of the first curing is shorter than the second curing time of the second curing. In this way, after the protective agent is attached to the front passivation anti-reflection layer 15, it is not completely cured, so that the roller with the pyramid-shaped protrusion on the surface can be embossed to form the protective agent that has been preliminarily shaped into the morphology of the pyramid velvet surface. Preferably, the irradiation energy of the first curing and / or the second curing is 1300mj / cm 2 ~1700mj / cm 2 The curing effect is better within the range of 1500 mj / cm 2 and values ​​close to it.

[0058] Alternatively, in some other scenarios, the protective layer 16 can also be formed by spraying a protective agent, wherein the spray printing includes spraying a protective agent in the shape of ink drops on at least a portion of the front passivation anti-reflection layer 15 to form a protective layer 16 having a pyramid velvet surface on the front passivation anti-reflection layer 15. Specifically, by directly spraying the protective agent, the protective agent in the shape of ink drops can be directly formed on the front passivation anti-reflection layer 15, and after one-time curing, a protective layer 16 with a pyramid velvet surface morphology is formed.

[0059] On the other hand, the protective layer 16 can also be formed by screen printing a protective agent, wherein the screen printing screen mold has a pyramid shape. The screen printing step includes printing the protective agent on at least part of the front passivation anti-reflection layer 15 through the screen mold to form the protective layer 16 with a pyramid velvet surface on the front passivation anti-reflection layer 15.

[0060] This application refers to Figure 8 A method 20 for preparing a back contact battery (hereinafter referred to as "preparation method 20") is proposed. Figure 8 , the preparation method 20 comprises the following steps:

[0061] Step 21 is to prepare a silicon substrate, which includes a substrate front side close to sunlight and a substrate back side away from sunlight. Step 22 is to prepare a first doping region, an isolation region, and a second doping region on the back side of the substrate, wherein the first doping region and the second doping region have different doping elements, and the isolation region is located between the first doping region and the second doping region on the back side of the substrate. Step 23 is to prepare a front passivation anti-reflection layer on the front side of the substrate. Step 24 is to prepare a protective layer on at least part of the front passivation anti-reflection layer, and the protective layer includes a resin material.

[0062] In some embodiments, preferably, the back-contact battery prepared by preparation method 20 has a battery edge, and step 24 of preparing the protective layer includes preparing a protective layer having a metal velvet surface in an edge protection zone, and the outer side of the edge protection zone closer to the battery edge is between 0.1 mm and 10 mm away from the battery edge.

[0063] On the other hand, preferably, step 24 of preparing the protective layer includes preparing a protective layer having a pyramid velvet surface. Specifically, step 24 of preparing the protective layer can be performed by different replaceable preparation process means. Three preferred embodiments are listed below.

[0064] First, step 24 of preparing the protective layer can be achieved by spraying a protective agent on at least part of the front passivation anti-reflection layer and performing a first curing; embossing the protective agent with a roller having pyramid-shaped protrusions so that the protective agent presents a pyramid morphology; and performing a second curing. Preferably, the first curing time is 2s to 4s, and / or the second curing time is 4s to 8s, and / or the irradiation energy range of the first curing and the second curing is 1300mj / cm 2 ~1700mj / cm 2 , exemplarily, the irradiation energies of the first curing and the second curing can be set to be the same or similar.

[0065] Second, step 24 of preparing the protective layer can be achieved by: spraying a protective agent on at least a portion of the front passivation anti-reflection layer, while controlling the protective agent to be in the shape of ink drops so that the protective agent presents a pyramid morphology when attached to the front passivation anti-reflection layer; and performing photocuring.

[0066] Third, step 24 of preparing the protective layer can also be achieved in the following manner: preparing a screen mold with pyramid protrusions; printing a protective agent on at least part of the front passivation anti-reflection layer through the screen mold so that the protective agent presents a pyramid morphology when attached to the front passivation anti-reflection layer; and performing light curing.

[0067] Regardless of which of the above methods is used, a protective layer with a pyramid velvet morphology can be formed in the back contact cell, thereby further improving the anti-reflection effect of the back contact cell surface on incident light. Fig. 9 It shows that based on Figure 8 A specific implementation of the preparation method 20 shown is a preparation method 30 for a back contact battery (hereinafter referred to as "preparation method 30"). Figure 3 , the preparation method 30 comprises the following steps:

[0068] Step 31 is polishing the silicon substrate when preparing the silicon substrate;

[0069] Step 32 is to prepare the first doping region by using LPCVD and boron diffusion;

[0070] Step 33 is to remove the borosilicate glass in a local area on one side of the back side of the substrate by laser;

[0071] Step 34: Clean and remove the first doped region in a local area on one side of the back side of the substrate, and perform phosphorus diffusion to prepare a second doped region;

[0072] Step 35 is to clean and remove the borosilicate glass and / or phosphosilicate glass on the front side of the substrate and / or the side of the substrate, and to perform texturing on one side of the front side of the substrate;

[0073] Step 36 is to prepare double-sided aluminum oxide and a front passivation anti-reflection layer on the front side of the substrate;

[0074] Step 37 is to prepare a first electrode and a second electrode on the back side of the substrate; and

[0075] Step 38 is to prepare a protective layer on at least a portion of the front passivation anti-reflection layer.

[0076] Preparation method 30 is a specific implementation method based on preparation method 20, but the present application is not limited thereto. In addition, since preparation method 20 and preparation method 30 can be used to prepare Figure 1 The back contact battery shown, therefore, other details about the preparation method 20 and the preparation method 30 can also refer to the previous description, which will not be repeated here.

[0077] It should be noted that in this application Figure 8 and Fig. 9 Flowcharts are used to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed precisely in order. Instead, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0078] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0079] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0080] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more application embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0081] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which can be changed according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the method of general digit retention. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0082] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A back contact battery, characterized in that: include: A silicon substrate, the silicon substrate comprising a substrate front side close to sunlight and a substrate back side away from the sunlight; A first doping region, an isolation region, and a second doping region are located on the back side of the substrate, wherein the first doping region and the second doping region have different doping elements, and the isolation region is located between the first doping region and the second doping region on the back side of the substrate; A front passivation anti-reflection layer, located on the front side of the substrate; and A protective layer is located on at least a portion of the front passivation anti-reflection layer, wherein the protective layer comprises a resin material and covers 1% to 50% of the front surface of the substrate.

2. The back contact cell according to claim 1, characterized in that It also includes a battery edge and an edge protection zone, wherein the protection layer is located in the edge protection zone, and the outer side of the edge protection zone closer to the battery edge is between 0.1 mm and 10 mm away from the battery edge.

3. The back contact cell according to claim 2, characterized in that The width of the edge protection area is 0.005mm~10mm.

4. The back contact cell according to claim 1, characterized in that The protective layer has a pyramid velvet surface.

5. The back contact cell according to claim 4, characterized in that The protective layer is formed by roller embossing, wherein the surface of the roller has pyramid-shaped protrusions.

6. The back contact cell according to claim 5, characterized in that The protective layer is formed by attaching a protective agent on at least a portion of the front passivation anti-reflection layer, followed by a first curing, roller embossing, and a second curing, wherein a first curing time of the first curing is shorter than a second curing time of the second curing.

7. The back contact cell according to claim 6, characterized in that The irradiation energy of the first curing and / or the second curing is 1300 mj / cm 2 ~1700mj / cm 2 .

8. The back contact cell according to claim 4, characterized in that The protective layer is formed by spraying a protective agent, wherein the spray printing includes spraying the protective agent in the shape of ink drops on at least a portion of the front passivation anti-reflection layer to form a protective layer having the pyramid velvet surface on the front passivation anti-reflection layer.

9. The back contact cell according to claim 4, characterized in that The protective layer is formed by screen printing a protective agent, wherein the screen printing screen mold has a pyramid shape, and the screen printing includes printing the protective agent on at least a portion of the front passivation anti-reflection layer through the screen mold to form a protective layer having the pyramid velvet surface on the front passivation anti-reflection layer.

10. The back contact battery according to any one of claims 1 to 9, characterized in that: The silicon substrate is an N-type substrate or a P-type substrate.

11. The back contact battery according to any one of claims 1 to 9, characterized in that: The front side of the substrate is a velvet surface, and the side of the front passivation anti-reflection layer away from the front side of the substrate is also the velvet surface.

12. The back contact battery according to any one of claims 1 to 9, characterized in that: The front passivation anti-reflection layer includes aluminum oxide, silicon nitride and / or silicon oxynitride.

13. The back contact battery according to any one of claims 1 to 9, characterized in that: It also includes a back passivation anti-reflection layer located on a side of the first doped region, the isolation region and the second doped region away from the back side of the substrate, and the back passivation anti-reflection layer includes aluminum oxide and / or silicon nitride.

14. The back contact cell according to claim 13, characterized in that The invention also includes a first electrode and a second electrode, which pass through the back passivation anti-reflection layer on one side of the back side of the substrate and contact the first doped region and the second doped region respectively.

15. The back contact cell according to claim 1, characterized in that The protection layer is in a continuous or discontinuous straight line shape, or an irregular shape on the front side of the substrate of the back contact battery.

16. The back contact battery according to any one of claims 1 to 9, characterized in that: The thickness of the protection layer along a first direction perpendicular to the silicon substrate is 6 micrometers to 15 micrometers.

17. The back contact battery according to any one of claims 1 to 9, characterized in that: The protective layer has a transmittance greater than 80% for incident light in the wavelength range of 300 nanometers to 1200 nanometers.

18. The back contact battery according to any one of claims 1 to 9, characterized in that: The refractive index of the protective layer is less than 1.

6.

19. The back contact battery according to any one of claims 1 to 9, characterized in that: The resin material includes epoxy resin or acrylic resin.

20. A method for preparing a back contact battery, characterized in that: The steps include: Prepare a silicon substrate, wherein the silicon substrate comprises a substrate front side close to sunlight and a substrate back side away from the sunlight; Preparing a first doping region, an isolation region, and a second doping region on the back side of the substrate, wherein the first doping region and the second doping region have different doping elements, and the isolation region is located between the first doping region and the second doping region on the back side of the substrate; Preparing a front passivation anti-reflection layer on the front side of the substrate; and A protective layer is prepared on at least a portion of the front passivation anti-reflection layer, wherein the protective layer comprises a resin material and covers 1% to 50% of the front surface of the substrate.

21. The preparation method according to claim 20, characterized in that: The back contact battery has a battery edge, and the step of preparing the protective layer includes preparing the protective layer with a metal velvet surface in an edge protection zone, wherein the outer side of the edge protection zone closer to the battery edge is between 0.1 mm and 10 mm away from the battery edge.

22. The preparation method according to claim 20, characterized in that: The step of preparing the protective layer includes preparing a protective layer having a pyramid velvet surface.

23. The preparation method according to claim 22, characterized in that: The steps of preparing the protective layer include: Spraying a protective agent on at least a portion of the front passivation anti-reflection layer, and performing a first curing; Imprinting the protective agent by a roller having pyramid-shaped protrusions, so that the protective agent presents a pyramid morphology; and Perform a second curing.

24. The preparation method according to claim 23, characterized in that: The time of the first curing is 2s to 4s, and / or the time of the second curing is 4s to 8s, and / or the irradiation energy range of the first curing and the second curing is 1300mj / cm 2 ~1700mj / cm 2 .

25. The preparation method according to claim 22, characterized in that: The steps of preparing the protective layer include: Spraying a protective agent on at least a portion of the front passivation anti-reflection layer, while controlling the protective agent to be in the shape of ink drops, so that the protective agent presents a pyramid morphology when attached to the front passivation anti-reflection layer; and Perform light curing.

26. The preparation method according to claim 22, characterized in that: The steps of preparing the protective layer include: Preparing a screen mold having pyramidal protrusions; Printing a protective agent on at least a portion of the front passivation anti-reflection layer through the screen mold, so that the protective agent presents a pyramid morphology when attached to the front passivation anti-reflection layer; and Light curing.

27. The preparation method according to any one of claims 20 to 26, characterized in that: Also includes: polishing the silicon substrate during the preparation of the silicon substrate; The first doped region is prepared by LPCVD and boron diffusion; Removing the borosilicate glass in a local area on one side of the back side of the substrate by laser; Cleaning and removing the first doped region in the local area on one side of the back side of the substrate, and performing phosphorus diffusion to prepare a second doped region; Cleaning and removing the borosilicate glass and / or phosphosilicate glass on the front side of the substrate and / or the side of the substrate, and performing texturing on one side of the front side of the substrate; Preparation of double-sided aluminum oxide and preparation of a front passivation anti-reflection layer on the front side of the substrate; Prepare a first electrode and a second electrode on the back side of the substrate; as well as The protective layer is prepared on at least a portion of the front passivation anti-reflection layer.

28. A back contact battery pack, characterized in that: It comprises a plurality of back contact cells as described in any one of claims 1 to 19 stacked on each other, or a plurality of back contact cells stacked on each other and made according to the preparation method as described in claims 20 to 27.

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