Photovoltaic module

Abstract

The invention provides a photovoltaic module. The photovoltaic module comprises a battery, an adhesive film layer and glass which are sequentially stacked, the adhesive film layer comprises a glass surface adhesive film layer close to the glass and a conductive adhesive film layer close to the battery, the conductive adhesive film layer covers the battery and a welding strip on the surface of the battery, and the resistivity of the glass surface adhesive film layer is 105-1010 times that of the conductive adhesive film layer. According to the photovoltaic module provided by the invention, the problem of potential induced degradation can be solved while the efficiency of the photovoltaic module is improved.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaics, and in particular to a photovoltaic module. Background Art

[0002] The improvement of photovoltaic module efficiency and product reliability has always been the goal of photovoltaic module technology. The improvement of photovoltaic module efficiency includes the improvement of optical performance and electrical performance. The improvement of electrical performance is mainly achieved by reducing the square resistance of the battery and reducing the contact resistance between the paste, solder strip and various materials.

[0003] Photovoltaic modules increase the number of battery main grids to reduce the charge transfer path on the surface of the battery cell, thereby reducing contact resistance and improving the electrical performance of photovoltaic modules. However, since the frame of the photovoltaic module is grounded during operation, there is a potential difference between the inside of the photovoltaic module and the frame, and leakage current will be generated between the frame and the battery. Positively charged ions such as Na+ will enter the battery with the leakage current, causing the power of the photovoltaic module to decrease, and there will be a PID (Potential Induced Degradation) problem during use.

[0004] In order to overcome the above-mentioned defects of the prior art, there is an urgent need in the art for a photovoltaic module that can improve the efficiency of the photovoltaic module while solving the potential induced degradation problem. Summary of the invention

[0005] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0006] In order to overcome the above-mentioned defects in the prior art, the present invention provides a photovoltaic module, which can improve the efficiency of the photovoltaic module and solve the problem of potential induced degradation.

[0007] Specifically, the photovoltaic module provided by the present invention comprises a battery, a film layer and a glass stacked in sequence, wherein the film layer comprises a glass surface film layer close to the glass and a conductive film layer close to the battery, wherein the conductive film layer covers the battery and the welding strip on the surface of the battery, and the resistivity of the glass surface film layer is 10 times the resistivity of the conductive film layer. 5 ~10 10 times.

[0008] Preferably, in one embodiment of the present invention, the resistivity of the conductive film layer is less than 10 9 Ω·cm.

[0009] Preferably, in one embodiment of the present invention, the resistivity of the glass surface adhesive film layer is greater than 10 14 Ω·cm.

[0010] Preferably, in an embodiment of the present invention, the gram weight of the glass surface adhesive film layer is greater than the gram weight of the conductive adhesive film layer.

[0011] Preferably, in an embodiment of the present invention, the gram weight of the glass surface adhesive film layer is 2 / 3 to 4 / 5 of the total gram weight of the adhesive film layer.

[0012] Preferably, in one embodiment of the present invention, the battery is a double-sided battery, and the structures of the front and back sides of the battery are symmetrical, wherein the adhesive film layer and the glass are stacked in sequence on the front and back sides of the battery, respectively, and the conductive adhesive film layer of the adhesive film layer on the front side and the conductive adhesive film layer of the adhesive film layer on the back side are not conductive to each other.

[0013] Preferably, in an embodiment of the present invention, the photovoltaic module comprises a plurality of the cells, and the front side of the cell is connected in series with the back side of another cell via a welding ribbon to form a cell interconnection strip.

[0014] In addition, the preparation method of the photovoltaic module provided according to the second aspect of the present invention includes the steps of: stacking a conductive adhesive film layer, a glass surface adhesive film layer and glass on the battery in sequence to obtain a stacked component; pre-cross-linking the conductive adhesive film layer, and the pre-cross-linking degree is 30% to 50% to prevent the conductive adhesive film layer from short-circuiting; laminating the stacked component to obtain the photovoltaic module provided by any one of the above embodiments.

[0015] Preferably, in one embodiment of the present invention, before the lamination, the step of: placing the conductive adhesive film layer centrally on the battery surface and parallel to the battery surface, the area of ​​the conductive adhesive film layer is smaller than the area of ​​the battery, the conductive adhesive film layer covers the edge welding strip of the battery surface and keeps a distance from the edge of the battery to prevent the conductive adhesive film layer from short-circuiting.

[0016] Preferably, in one embodiment of the present invention, the extensibility of the conductive film layer after lamination is less than the difference between the width of the battery and the width of the conductive film layer before lamination, and the extensibility of the conductive film layer is the difference between the width of the conductive film layer after lamination and the width of the conductive film layer before lamination plus the relief distance.

[0017] Preferably, in an embodiment of the present invention, the battery comprises a silicon nitride layer and an aluminum oxide layer, and the silicon nitride layer and the aluminum oxide layer are wrapped in the conductive adhesive film layer.

[0018] The photovoltaic module provided by the present invention can block positively charged ions such as Na+ from entering the battery through a glass surface adhesive layer with high resistivity and high gram weight and a conductive adhesive layer with low resistivity and low gram weight, thereby solving the problem of potential induced decay and improving the efficiency of the photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0020] Figure 1 A schematic diagram showing a leakage path generated by an existing photovoltaic module;

[0021] Figure 2 A schematic diagram of voltage division of an existing photovoltaic module is shown;

[0022] Figure 3 A schematic diagram showing a photovoltaic module with a conventional stacked structure;

[0023] Figure 4 A schematic diagram showing a photovoltaic module with a laminated structure of existing film coating process modules is shown;

[0024] Figure 5 A schematic diagram of the structure of a photovoltaic assembly provided according to some embodiments of the present invention is shown;

[0025] Figure 6 shows a voltage division diagram of a photovoltaic module provided according to some embodiments of the present invention;

[0026] Figure 7 A circuit diagram of a conductive adhesive film layer and a battery of a photovoltaic module provided according to some embodiments of the present invention is shown;

[0027] Figure 8 A schematic diagram of the structure of a photovoltaic assembly provided according to some embodiments of the present invention is shown;

[0028] Fig. 9 A schematic diagram of a photovoltaic assembly including a plurality of cells provided according to some embodiments of the present invention is shown;

[0029] Fig.10 A schematic diagram showing a short circuit of a conductive adhesive film layer provided according to some embodiments of the present invention is shown;

[0030] Fig.11 A schematic diagram of a conductive adhesive film layer of a photovoltaic module provided according to some embodiments of the present invention is shown;

[0031] Fig.12A schematic diagram showing a conductive adhesive film layer before and after pre-crosslinking according to some embodiments of the present invention is shown; and

[0032] Fig.13 Schematic diagrams of photovoltaic modules before and after extension are shown according to some embodiments of the present invention.

[0033] Reference numerals:

[0034] 101: Main leakage paths;

[0035] 102: positively charged ions;

[0036] 110: border;

[0037] 120: Battery;

[0038] 121: welding strip;

[0039] 122: negative voltage;

[0040] 130: Glass;

[0041] 140: back panel;

[0042] 150: sealant;

[0043] 210: Glass;

[0044] 220: Adhesive film;

[0045] 230: silicon nitride layer;

[0046] 310: Battery;

[0047] 311: welding strip;

[0048] 320: Adhesive film;

[0049] 330: Glass;

[0050] 410: Battery;

[0051] 411: welding strip;

[0052] 420: Adhesive film;

[0053] 421: film layer;

[0054] 500: Photovoltaic panels;

[0055] 510: Battery;

[0056] 520: adhesive film layer;

[0057] 521: Glass surface adhesive film layer;

[0058] 522: conductive film layer;

[0059] 530: Glass;

[0060] 610: conductive film layer;

[0061] 620: Insulation layer;

[0062] 630: thin grid lines of the battery;

[0063] 640: Glass;

[0064] 650: Glass surface adhesive film layer;

[0065] 660: crystalline silicon layer;

[0066] 710: Total resistance R 总 ;

[0067] 711: Resistor R 导电胶膜层 ;

[0068] 712: Resistor R 电池 ;

[0069] 800: Photovoltaic panels;

[0070] 810: Bifacial battery;

[0071] 820, 840: adhesive film layer;

[0072] 821, 841: conductive film layer;

[0073] 822, 842: Glass surface adhesive film layer;

[0074] 830, 850: Glass;

[0075] 900: battery cell interconnection strip;

[0076] 910: Battery;

[0077] 920: welding strip;

[0078] 1001: contact position;

[0079] 1210: Linear structure;

[0080] 1220: Body (reticular) structure; and

[0081] L1, L2, L3: Width. DETAILED DESCRIPTION

[0082] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0083] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0084] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0085] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.

[0086] As mentioned above, the existing technology mainly improves the PID problem by increasing the resistivity of the film and reducing the leakage current, but it can only improve the PID problem, and the electrical performance is reduced; another existing technology reduces the resistivity of the silicon nitride of the battery to reduce the partial pressure of the silicon nitride layer, thereby reducing the offset voltage of the positive ions in the silicon nitride, but it cannot fundamentally solve the PID problem; in addition, the existing technology can also improve the PID problem by increasing the density of the back grid lines to reduce the resistance, but the grid lines blocking the battery will reduce the light-receiving area, resulting in a decrease in the power of the photovoltaic module, and the silicon nitride layer still has a portion exposed under the film, which cannot fundamentally solve the PID problem.

[0087] Please refer to Figure 1 , Figure 1 A schematic diagram showing leakage paths generated by existing photovoltaic modules is shown.

[0088] like Figure 1As shown, the photovoltaic module includes a frame 110, a battery 120, a welding strip 121 on the battery, a glass 130 and a back plate 140. The photovoltaic module is sealed by a sealant 150. To prevent leakage and lightning strike, the frame 110 of the photovoltaic module needs to be grounded, and the voltage of the frame 110 is 0V. Figure 1 In the embodiment shown, the battery 120 inside the photovoltaic module is a P-type crystalline silicon solar cell, and a potential difference is formed between the negative voltage 122 of the battery 120 inside the photovoltaic module and the voltage of the grounded frame 110. Under the action of the potential difference, multiple leakage current channels are generated, such as Figure 1 The main leakage path 101 is shown. Positively charged ions 102 such as Na+ on the glass 130 will enter the battery 120 along the direction of the leakage current channel.

[0089] When positively charged ions such as Na+ enter the battery, two PID failure conditions will occur: PID-s and PID-p. Among them, PID-s is when positively charged ions such as Na+ enter the battery PN junction to form a leakage channel, causing battery leakage, thereby reducing the power of the photovoltaic module. PID-p is when positively charged ions such as Na+ enter the insulating layer of the battery under the action of the electric field, such as the silicon nitride and aluminum oxide layers, causing the interface to be positively charged, thereby causing the power of the photovoltaic module to attenuate.

[0090] Please refer to Figure 2 , Figure 2 A schematic diagram of voltage division of an existing photovoltaic module is shown.

[0091] like Figure 2 As shown, positively charged ions such as Na+ rely on electric field displacement to enter the silicon nitride layer 230 inside the battery through the glass 210 and the film 220. Due to the differences in material density and resistivity of the glass 210, the film 220 and the silicon nitride layer 230 inside the battery, the partial pressures of the glass 210, the film 220 and the silicon nitride layer 230 inside the battery are different.

[0092] Existing photovoltaic modules mainly improve the PID problem by increasing the resistivity of the film and reducing the leakage current, but this can only improve the PID problem and will cause the electrical performance of the photovoltaic modules to deteriorate; alternatively, existing photovoltaic modules reduce the resistivity of the insulating layer inside the battery to reduce the partial pressure of the insulating layer, thereby reducing the offset voltage of the positive ions in the insulating layer, but this cannot fundamentally solve the PID problem.

[0093] Please refer to Figure 3 and Figure 4 , Figure 3 A schematic diagram showing a photovoltaic module with a conventional laminated structure is shown. Figure 4 A schematic diagram of a photovoltaic module with a laminated structure of existing film-coating process modules is shown.

[0094] like Figure 3 As shown, in the conventional process component stacking structure, the front and back of the battery 310 are symmetrical structures. Taking the front of the battery 310 as an example, the front of the battery 310 is provided with a soldering strip 311, a film 320 and a glass 330. The front and back of the battery 310 both have a layer of film 320. Figure 4 As shown, in the laminated structure of the laminating process component, the front and back of the battery 410 are symmetrical structures. Taking the front of the battery 410 as an example, the front of the battery 410 is respectively provided with a soldering strip 411, a film 420 and a glass 430. Due to the difference in the functions of the film, the film 420 can be divided into two layers. The film layer 421 close to the battery 410 is used to bond the soldering strip 411 and the battery 410 to form a good ohmic contact, thereby achieving the effect of 0BB (0Busbar) welding of the battery 410.

[0095] Combination Figures 2 to 4 It can be seen that both the conventional process stacked structure photovoltaic modules and the film coating process stacked structure photovoltaic modules have the PID problem. In order to overcome the above defects of the prior art, the present invention provides a photovoltaic module that can improve the efficiency of the photovoltaic module while solving the potential induced degradation problem.

[0096] In early batteries, the back of aluminum back field batteries and heterojunction batteries did not have PID problems. The back of aluminum back field batteries is covered with aluminum paste. For example, in PERC batteries (Passivated Emitter and Rear Cell), after using aluminum back field (i.e., covering the back of the battery with aluminum paste), there is no back PID problem; but after PERC batteries are changed to bifacial batteries, the aluminum back field is changed to aluminum grid lines that expose silicon nitride, and PERC batteries have PID problems. The surface of heterojunction batteries is a conductive TCO (Transparent Conductive Oxide) layer without an insulating layer (i.e., a silicon nitride layer). Therefore, the surface of the heterojunction battery is at the same potential as the interior of the battery. It can be seen from the back of the aluminum back field battery and the heterojunction battery that in the absence of an electric field, positively charged ions such as Na+ cannot be offset to the interior of the battery, so there is no PID problem. Based on this, the present invention proposes a photovoltaic module.

[0097] Please refer to Figure 5 , Figure 5 A schematic structural diagram of a photovoltaic assembly provided according to some embodiments of the present invention is shown.

[0098] like Figure 5As shown, the photovoltaic module 500 combines the voltage division principle of PID failure and has a double-layer anti-PID film. The photovoltaic module 500 may include a battery 510, a film layer 520 and a glass 530 stacked in sequence. The film layer 520 may include a glass surface film layer 521 close to the glass and a conductive film layer 522 close to the battery. The conductive film layer 522 may cover the battery 510 and the welding strip on the surface of the battery 510.

[0099] The glass surface adhesive film layer 521 of the adhesive film layer 520 is a high-weight, high-resistivity adhesive film, and the conductive adhesive film layer 522 is a low-weight, low-resistivity adhesive film. The conductive adhesive film layer 522 can be used to fix the tin-coated solder strip to the battery 510, and the glass surface adhesive film layer 521 can be a conventional process adhesive film, which is laid on the glass 530.

[0100] The weight of the glass surface film layer 521 may be greater than the weight of the conductive film layer 522. In some embodiments, the weight of the glass surface film layer 521 may be 2 / 3 to 4 / 5 of the total weight of the film layer 520, and the weight of the conductive film layer 522 may be 1 / 3 to 1 / 5 of the total weight of the film layer 520.

[0101] The resistance of the glass surface adhesive film layer 521 and the conductive adhesive film layer 522 can be achieved by adjusting the resistivity of the formula. The resistivity of the glass surface adhesive film layer 521 can be 5 to 10 (10 5 ~10 10 In some embodiments, the resistivity of the glass surface adhesive film layer 521 may be greater than 10 14 Ω·cm, the resistivity of the conductive film layer 522 can be less than 10 9 Ω·cm.

[0102] The proportion of the low-resistivity conductive film layer 522 in the film layer 520 is relatively low, thereby ensuring that the overall resistivity of the film layer 520 is slightly different from that of a high-resistivity film layer directly used, thereby ensuring that the partial pressure of the silicon nitride layer in the battery 510 remains unchanged.

[0103] In addition, the glass surface adhesive film layer 521 with high gram weight and high resistivity can increase the offset voltage of the glass surface adhesive film layer 521, thereby increasing the partial pressure ratio of the glass surface adhesive film layer 521. The conductive adhesive film layer 522 with low gram weight and low resistivity can reduce the partial pressure of the conductive adhesive film layer 522, thereby reducing the offset efficiency of positively charged ions in the conductive adhesive film layer 522.

[0104] The conductive film layer wraps the battery surface. In some embodiments, the battery may include a silicon nitride layer and an aluminum oxide layer, and the silicon nitride layer and the aluminum oxide layer may be wrapped in the conductive film layer. Since the conductive film layer is conductive, it forms an equipotential with the silicon nitride layer, the aluminum oxide layer and the battery grid line wrapped inside the conductive film layer, so that there is no electric field inside the conductive film layer, which can drive positively charged ions such as Na+ into the battery, thereby achieving the effect of solving the PID problem. In addition, the conductive film layer covering the battery surface can also reduce the series resistance of the photovoltaic module.

[0105] Please refer to Figure 6 , Figure 6 A voltage division diagram of a photovoltaic module provided according to some embodiments of the present invention is shown.

[0106] like Figure 6 As shown, the conductive film layer 610 wraps the insulating layer 620 (i.e., silicon nitride layer) and the fine grid lines 630 of the battery. Based on the conductive properties of the conductive film layer 610, the conductive film layer 610, the insulating layer 620, and the fine grid lines 630 of the battery are equipotential, and there is no voltage in the insulating layer 620. The resistivity of the glass 640 and the glass surface film layer 650 is 5 to 10 orders of magnitude higher than that of the conductive film layer 610. Therefore, the partial pressure of the glass 640 and the glass surface film layer 650 is higher than that of the conductive film layer 610, thereby reducing the displacement efficiency of positively charged ions in the conductive film layer 610. Moreover, after the positively charged ions such as Na+ reach the conductive film layer 610 from the glass 640 and the glass surface film layer 650, there is no electric field because the conductive film layer 610, the insulating layer 620, and the fine grid lines 630 of the battery have equal potentials, so the positively charged ions such as Na+ cannot be driven into the insulating layer 620 and the crystalline silicon layer 660 inside the battery. The positively charged ions such as Na+ can only enter the battery by thermal diffusion, and the migration rate of the thermal diffusion method is much lower than the migration rate of the electric field drift (basically negligible), so the photovoltaic module provided by the present invention can achieve the effect of solving the PID problem.

[0107] In this way, the photovoltaic module provided by the present invention combines the PID failure principle and uses a low-resistivity conductive film layer as the covering layer. The conductive film layer has the functions of light transmission and conductivity, which can reduce the contact resistance on the surface of the battery and achieve the effect of solving the PID problem and improving the power of the photovoltaic module without affecting other performances of the photovoltaic module.

[0108] For further information, please refer to Figure 7 , Figure 7 A circuit diagram of a conductive adhesive film layer and a battery of a photovoltaic module provided according to some embodiments of the present invention is shown.

[0109] like Figure 7As shown, the conductive film layer covers the battery surface and is in parallel with the battery paste and the solder strip. Through the parallel connection of the conductive film layer and the battery, that is, the resistance R 导电胶膜层 711 and resistor R 电池 712 parallel connection can reduce the total resistance R of the photovoltaic module 总 710, thereby effectively improving the series resistance of the photovoltaic module and enhancing the electrical performance of the photovoltaic module.

[0110] In some embodiments, the battery may be a double-sided battery, and the front and back sides of the battery have symmetrical structures, wherein the front and back sides of the battery are respectively stacked with adhesive film layers and glass, and the conductive adhesive film layer of the adhesive film layer on the front side is not conductive to the conductive adhesive film layer of the adhesive film layer on the back side.

[0111] Please refer to Figure 8 , Figure 8 A schematic structural diagram of a photovoltaic assembly provided according to some embodiments of the present invention is shown.

[0112] like Figure 8 As shown, the photovoltaic module 800 may include a bifacial cell 810. The photovoltaic module 800 may also include a film layer 820 and a glass 830 sequentially stacked on the front side of the bifacial cell 810, and the film layer 820 may include a conductive film layer 821 and a glass surface film layer 822. The front and back sides of the bifacial cell 810 have symmetrical structures, and the photovoltaic module 800 may also include a film layer 840 and a glass 850 sequentially stacked on the back side of the bifacial cell 810, and the film layer 840 may include a conductive film layer 841 and a glass surface film layer 842.

[0113] The conductive film layer 821 and the conductive film layer 841 used for bonding the soldering tape and the battery near the front and back of the battery can be a conductive film with low resistivity, and the conductive film layer 821 and the conductive film layer 841 have a low partial pressure. In addition, the conductive film layer 821 and the conductive film layer 841 can play an effect similar to the complete coverage of the aluminum paste on the back of the PERC battery, and the bifacial battery 810 and the conductive film layer 821 and the conductive film layer 841 have equal potentials, so that the positively charged ions cannot be offset into the bifacial battery 810 in the absence of an electric field, thereby solving the PID problem. In addition, because the film layer 820 and the film layer 840 have good transmittance, they can be used on the front and back of the bifacial battery 810, and can solve the PID problem and reduce the series resistance of the photovoltaic module 800 without reducing the light input to the photovoltaic module 800.

[0114] In some embodiments, a photovoltaic module may include a plurality of cells, and the front side of a cell may be connected in series with the back side of another cell via a welding ribbon to form a cell interconnection strip.

[0115] Please refer to Fig. 9 , Fig. 9A schematic diagram of a photovoltaic module including a plurality of cells provided according to some embodiments of the present invention is shown.

[0116] like Fig. 9 As shown, a photovoltaic module may include multiple cells 910, and the front of a cell 910 and the back of another cell 910 may be connected in series through a tin-coated solder strip 920 to form a cell interconnection bar 900. After forming the cell interconnection bar 900, the cell 910 and the solder strip 920 are packaged and laminated using a conductive adhesive film layer, a glass surface adhesive film layer, glass, a backplane, etc. to form a photovoltaic module.

[0117] The photovoltaic module provided by the present invention can be obtained by the method for preparing the photovoltaic module provided by the present invention. The method for preparing the photovoltaic module can include the steps of: sequentially stacking a conductive adhesive film layer, a glass surface adhesive film layer and glass on the battery to obtain a stacked module; and laminating the stacked modules to obtain the photovoltaic module.

[0118] Please refer to Fig.10 , Fig.10 A schematic diagram of a short circuit of a conductive adhesive film layer provided according to some embodiments of the present invention is shown.

[0119] like Fig.10 As shown, there may be a risk of short circuit in the conductive film layer of photovoltaic modules. The preparation process of photovoltaic modules is usually carried out under high temperature and high pressure, and the conductive film layer will melt at high temperature. Therefore, in a high temperature and high pressure environment, the conductive film layer may overflow due to pressure after melting, causing the conductive film layers of two adjacent cells to contact or the conductive film layers on the front and back of a bifacial cell to contact, such as Fig.10 As shown in the middle contact position 1001, a short circuit occurs, which affects the performance of the photovoltaic module.

[0120] In some embodiments, before lamination, the conductive film layer of the photovoltaic module can be centered on the battery surface and parallel to the battery surface. The area of ​​the conductive film layer is smaller than the area of ​​the battery. The conductive film layer covers the edge welding strip of the battery surface and keeps a distance from the edge of the battery to prevent the conductive film layer from short-circuiting.

[0121] Please refer to Fig.11 , Fig.11 A schematic diagram of a conductive adhesive film layer of a photovoltaic module provided according to some embodiments of the present invention is shown.

[0122] like Fig.11 As shown, the conductive film layer of the photovoltaic module is positioned with the battery before lamination, centered on the battery surface and parallel to the battery surface. The area of ​​the conductive film layer can be smaller than the battery area, but because the conductive film layer needs to fix the solder strip on the battery surface, the film layer covers the edge of the tin-coated solder strip on the battery surface and maintains a sufficient distance from the edge of the battery.

[0123] In some embodiments, the conductive adhesive film layer of the photovoltaic module may be pre-crosslinked before lamination, so that the crosslinking degree of the conductive adhesive film layer before lamination is 30% to 50%, so as to prevent the conductive adhesive film layer from short-circuiting.

[0124] Please refer to Fig.12 , Fig.12 Schematic diagrams of a conductive adhesive film layer before and after pre-crosslinking according to some embodiments of the present invention are shown.

[0125] exist Fig.12 In the illustrated embodiment, the thermosetting adhesive film can form crosslinks (i.e., small molecules polymerize to form macromolecules) under high temperature or ultraviolet light irradiation. After pre-crosslinking, the adhesive film can be transformed from a linear structure 1210 to a three-dimensional (network) structure 1220. As the degree of crosslinking increases, the fluidity of the conductive adhesive film layer decreases. The degree of crosslinking of photovoltaic modules is generally required to be 75%-95%. The conductive adhesive film layer can be pre-crosslinked before lamination and then the photovoltaic modules can be laminated to meet the crosslinking requirements of the photovoltaic modules. Preferably, the degree of crosslinking of the pre-crosslinking can be 30%-50%. Therefore, by pre-crosslinking the conductive adhesive film layer, the fluidity of the conductive adhesive film layer at high temperature can be effectively reduced to prevent short circuits between the conductive adhesive film layers.

[0126] In some embodiments, the photovoltaic modules can be simultaneously treated before lamination. Fig.11 The positioning placement scheme shown and Fig.12 The pre-crosslinking scheme shown is to better prevent short circuits between conductive film layers.

[0127] In some embodiments, the photovoltaic module can be tested for the ductility of the conductive film layer after lamination to ensure that there is no short circuit between the conductive film layers. Preferably, the conductive film layer to be tested for ductility can be tested before lamination. Fig.11 Positioning and / or placement options shown Fig.12 The pre-crosslinking scheme shown is used for processing. The elongation of the conductive film layer after lamination is less than the difference between the width of the battery and the width of the conductive film layer before lamination. The elongation of the conductive film layer is the difference between the width of the conductive film layer after lamination and the width of the conductive film layer before lamination plus the relief distance. The relief distance is a buffer value and can be set according to the battery boundary requirements and actual conditions.

[0128] Please refer to Fig.13 , Fig.13 Schematic diagrams of photovoltaic modules before and after extension are shown according to some embodiments of the present invention.

[0129] like Fig.13As shown, the ductility of the conductive film layer can be tested after lamination. The ductility test can be combined with the battery boundary requirements to determine whether the width of the conductive film layer after lamination meets the requirements, thereby ensuring that the conductive film layer after lamination will not short-circuit. Fig.13 As shown, the width of the adhesive film layer after lamination is width L1, the width of the adhesive film layer before lamination is width L2, and the width of the battery is width L3. In some embodiments, the extension degree = (L1-L2) + X < L3-L2. Where X is the slowing distance.

[0130] In summary, the photovoltaic module provided by the present invention can block positively charged ions such as Na+ from entering the battery through a glass surface adhesive layer with high resistivity and high gram weight and a conductive adhesive layer with low resistivity and low gram weight, thereby solving the PID problem and improving the efficiency of the photovoltaic module.

[0131] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photovoltaic module, comprising a battery, a film layer and a glass stacked in sequence, characterized in that: The adhesive film layer includes a glass surface adhesive film layer close to the glass and a conductive adhesive film layer close to the battery. The conductive adhesive film layer covers the battery and the welding strip on the surface of the battery. The resistivity of the glass surface adhesive film layer is 10 times that of the conductive adhesive film layer. 5 ~10 10 times.

2. The photovoltaic module according to claim 1, characterized in that: The resistivity of the conductive film layer is less than 10 9 Ω·cm.

3. The photovoltaic module according to claim 1, characterized in that: The resistivity of the glass surface adhesive film layer is greater than 10 14 Ω·cm.

4. The photovoltaic module according to claim 1, characterized in that: The gram weight of the glass surface adhesive film layer is greater than the gram weight of the conductive adhesive film layer.

5. The photovoltaic module according to claim 4, characterized in that: The gram weight of the glass surface adhesive film layer is 2 / 3 to 4 / 5 of the total gram weight of the adhesive film layer.

6. The photovoltaic module according to claim 1, characterized in that: The battery is a double-sided battery, and the structures of the front and back sides of the battery are symmetrical, wherein the adhesive film layer and the glass are stacked in sequence on the front and back sides of the battery respectively, and the conductive adhesive film layer of the adhesive film layer on the front side is not conductive to the conductive adhesive film layer of the adhesive film layer on the back side.

7. The photovoltaic module according to claim 6, characterized in that: The photovoltaic module comprises a plurality of the cells, and the front side of the cell is connected in series with the back side of another cell via a welding strip to form a cell interconnection strip.

8. A method for preparing a photovoltaic module, characterized in that: Includes steps: sequentially stacking a conductive adhesive film layer, a glass surface adhesive film layer and glass on the battery to obtain a stacked assembly; Pre-crosslinking the conductive adhesive film layer, wherein the degree of crosslinking is 30% to 50%, so as to prevent the conductive adhesive film layer from short-circuiting; The stacked components are laminated to obtain the photovoltaic component according to any one of claims 1 to 7.

9. The method for preparing a photovoltaic module according to claim 8, characterized in that: Prior to the lamination, the method further comprises the steps of: The conductive film layer is placed centrally on the battery surface and parallel to the battery surface. The area of ​​the conductive film layer is smaller than the area of ​​the battery. The conductive film layer covers the edge welding strip of the battery surface and keeps a distance from the edge of the battery to prevent the conductive film layer from short-circuiting.

10. The method for preparing a photovoltaic module according to any one of claims 8 or 9, characterized in that: The ductility of the conductive film layer after lamination is less than the difference between the width of the battery and the width of the conductive film layer before lamination. The ductility of the conductive film layer is the difference between the width of the conductive film layer after lamination and the width of the conductive film layer before lamination plus the relief distance.

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