Imbricated tile assembly

Abstract

According to the imbricated assembly provided by the utility model, the combination of a conductive connecting material (low-temperature solder) and a conventional fixed structural adhesive is adopted to replace a conductive adhesive, and the low-temperature solder is used as an electrical connection functional material of a small battery piece, so that the transmission of current carriers is realized; and the conventional fixed structural adhesive is used as a core material for fixing the mechanical architecture of the imbricate assembly, and the position of the conductive connecting material can be flexibly arranged according to different typesetting modes, so that the conductive connecting material is stably and electrically connected with the front battery and the rear battery, the strength and the reliability of connection between the imbricate assembly pieces are improved, and the power of the imbricate assembly is improved. According to the utility model, the use of low-temperature solder is reduced, the consumption of noble metal is effectively reduced, the cost per kilowatt hour is further reduced, the electrical properties of the original imbricate assembly are maintained, and the structural stability and the electrical property stability of the imbricate assembly are further improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a shingled assembly. Background Art

[0002] A shingled module is a photovoltaic module construction method in which small cell sheets are stacked together through a specific connection method and laminated to form a cell string, thereby improving the power output and efficiency of the photovoltaic module. During the shingled module production process, the cell sheets are stacked end to end and the electrical and mechanical connections between the cell sheets are achieved through specific materials and processes.

[0003] Traditional shingled modules use conductive adhesive (ECA, typically containing 70-80% silver by mass) to connect the cell shingles. This adhesive is primarily composed of silver particles, resulting in high costs. As silver is a precious metal, its price fluctuations and required silver content directly impact the overall manufacturing cost of shingled modules.

[0004] Furthermore, the electrical conductivity of shingled modules depends on the contact between the conductive particles within the conductive adhesive. If the silver content in the adhesive decreases, the conductivity will significantly deteriorate, affecting the overall efficiency of the module. The stability of this conductive method is also affected by the uniformity of the adhesive application and the quality of the contact.

[0005] To reduce costs while maintaining or improving electrical conductivity, new material alternatives need to be explored. The low-temperature conductive silver paste used in existing technologies, while offering high packaging density, still has high packaging costs, and it is difficult to maintain excellent electrical conductivity while reducing costs.

[0006] Furthermore, the structural stability of shingled modules is also a significant issue. Maintaining or even improving the mechanical stability and durability of shingled modules while reducing costs is a key challenge for manufacturers. Utility Model Content

[0007] The present application provides a shingled assembly to solve at least one of the problems raised in the above technical background.

[0008] A first aspect of the present application is to provide a shingled assembly, comprising:

[0009] Photovoltaic ultra-clear glass, photovoltaic backsheet;

[0010] Multiple (≥2) battery strings, composed of multiple (≥2) battery cells connected in series in a shingled manner, with a first adhesive film layer provided between one side of the battery string and the photovoltaic ultra-clear glass, and a second adhesive film layer provided between the other side of the battery string and the photovoltaic backsheet;

[0011] The front side of the battery chip is provided with a main grid line, and the back side is printed with back silver;

[0012] joining materials, including structural adhesives and low-temperature solders;

[0013] The connecting material is applied between two adjacent battery chips, front and back, to connect the battery chips and form a series circuit.

[0014] Preferably, the structural adhesive is used to connect battery chips that are close to each other, and the structural adhesive does not include conductive particles.

[0015] Preferably, the low-temperature solder contains conductive particles for electrically connecting two battery chips close to each other.

[0016] Preferably, the structural adhesive forms adhesive spots after curing.

[0017] Preferably, the low-temperature solder forms a low-temperature solder joint after solidification.

[0018] Preferably, the low-temperature solder is provided on the busbars of the lower battery chips, so that electrical connection is achieved between the back silver of the upper battery chips and the busbars of the lower battery chips.

[0019] In a preferred embodiment, the width of the low-temperature solder joint after solidification is not less than the width of the main grid line, ensuring a certain assembly error margin.

[0020] Preferably, the width of the low-temperature solder joint after solidification is 80-150% of the width of the main grid line, preferably 110-150%, more preferably 120-140%.

[0021] In a preferred embodiment, the solder joint formed after the low-temperature solder is thermally cured has a thickness of 10-60 μm, preferably 20-50 μm, and more preferably 30-40 μm.

[0022] In a preferred embodiment, the structural adhesive is provided at the non-low-temperature solder points at the connection between the two battery chips, and is used to connect the two battery chips that are close to each other to achieve reinforcement of mechanical properties.

[0023] Preferably, the structural adhesive may be provided between two low-temperature solder joints, or may be provided on one side of a low-temperature solder joint.

[0024] In a preferred embodiment, the adhesive dots formed after the structural adhesive is thermally cured have a thickness of 10-60 μm, preferably 20-50 μm, and more preferably 30-40 μm.

[0025] In a preferred embodiment, the width of the main grid line is 1.0-1.1 mm.

[0026] In a preferred embodiment, the distance between two adjacent main grid lines is 4.8-5.0 mm.

[0027] In a preferred embodiment, the width of the low-temperature solder joint on the main grid line after solidification is 1.33 mm.

[0028] In a preferred embodiment, the width of the adhesive spot of the structural adhesive between two adjacent main grid lines is 3.42 mm.

[0029] Preferably, the conductive particles are selected from: metal conductive particles (such as micropowders or nanoparticles of metals such as silver, copper, aluminum, and gold), carbon conductive particles (such as graphene), metal oxide conductive particles (such as micropowders or nanoparticles of metal oxides such as copper oxide, iron oxide, and zinc oxide), conductive polymer particles (such as micropowders or nanoparticles of polyaniline and polythiophene), titanium dioxide particles, and fluoride particles, or a combination thereof.

[0030] Preferably, the structural adhesive is selected from one or more combinations of epoxy heat-curing adhesives, acrylic heat-curing adhesives, and silicone heat-curing adhesives.

[0031] Preferably, the curing temperature of the structural adhesive is 80-220°C, preferably 90-200°C, and more preferably 100-180°C.

[0032] Preferably, the low-temperature solder is selected from: one or more combinations of Sn-Bi eutectic low-temperature solder, near-eutectic low-temperature solder, hypoeutectic alloy low-temperature solder, Sn-In series alloy low-temperature solder, and Sn paste low-temperature solder.

[0033] Preferably, the curing temperature of the low-temperature solder is 80-220°C, preferably 90-200°C, more preferably 100-180°C.

[0034] More preferably, the thermal curing temperature of the structural adhesive and the low-temperature solder may be the same or different.

[0035] More preferably, the structural adhesive and the low-temperature solder having the same thermal curing temperature can be cured at one time under the same curing conditions, which facilitates the adjustment of the production process.

[0036] More preferably, the adhesive strip formed after the low-temperature solder is solidified contains 40-95% (mass fraction) of silver, preferably 50-90% (mass fraction) of silver, and more preferably 60-80% (mass fraction) of silver.

[0037] A second aspect of the present invention provides a method for preparing a battery string for a shingled module, comprising the following steps:

[0038] Lay the lower battery sheet;

[0039] Apply low-temperature solder points to the busbars at the tail end of the battery chip, and then apply structural adhesive to the non-low-temperature solder points at the tail end of the battery chip;

[0040] Lay the upper battery sheet;

[0041] By irradiating with ultraviolet light of a preset wavelength (such as 190-405nm), the structural adhesive is cured in a very short time (such as 3-10s).

[0042] Preferably, the low temperature solder is applied by dispensing or stencil printing.

[0043] Preferably, the structural adhesive is applied by dispensing or screen printing.

[0044] In this application specification, "shingling method" is a special method of connecting battery cells. In this connection method, the battery cells are cut into smaller units and connected front to back through specific conductive materials (such as conductive glue, low-temperature solder, etc., referred to as low-temperature solder in this application) to form a series circuit.

[0045] In this application, "back silver" refers to the silver paste on the back of photovoltaic ultra-clear glass, also known as the negative electrode silver paste. Back silver typically contains less silver than front silver paste and requires less complex production processes. With a light transmittance exceeding 91.5%, photovoltaic ultra-clear glass effectively reduces the reflection and scattering of sunlight, increasing the light-receiving area and power generation efficiency of photovoltaic modules.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention provides a shingled assembly that utilizes a combination of a conductive connecting material (low-temperature solder) and a conventional fixed structural adhesive to replace the conductive adhesive. The low-temperature solder serves as the functional material for the electrical connection of the battery cells, enabling carrier transmission; the conventional fixed structural adhesive serves as the core material for fixing the mechanical structure of the shingled assembly. The conductive connecting material can be flexibly arranged in different layouts to form a stable electrical connection with the front and rear cells, thereby improving the strength and reliability of the connection between the shingled assembly sheets and increasing the power of the shingled assembly. The present invention reduces the use of low-temperature solder, effectively reduces precious metal consumption, further reduces the cost per kilowatt-hour, maintains the electrical characteristics of the original shingled assembly, and further improves the structural stability and electrical performance stability of the shingled assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 This is a schematic structural diagram of the shingled assembly in Example 1 of the present utility model.

[0050] The following are the descriptions of the reference numerals:

[0051] 1. Front of the battery; 2. Back of the battery; 3. Back silver; 4. Structural adhesive; 5. Low-temperature solder; 6. Front main grid line. DETAILED DESCRIPTION

[0052] This application provides a shingled assembly and a method for manufacturing the same. To clarify the purpose, technical solutions, and effects of this application, the application is further described below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the content of this application and are not intended to limit the content of this application.

[0053] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this manner are interchangeable under appropriate circumstances. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0054] Example 1:

[0055] This embodiment provides a shingled assembly, including:

[0056] (1) Photovoltaic ultra-white glass and photovoltaic backboard: Photovoltaic ultra-white glass is ultra-white cloth-textured tempered glass for photovoltaic use, and photovoltaic backboard is ordinary TPT backboard.

[0057] (2) Adhesive films, including:

[0058] Front and back films: Use ethylene-vinyl acetate copolymer (EVA) or polyolefin elastomer (POE) materials with high light transmittance and low water vapor permeability to ensure good adhesion, cushioning effect and electrical insulation performance.

[0059] (3) A battery string is composed of a plurality of (≧2) battery cells connected in series in a shingled manner: the battery cell includes a battery front face 1 and a battery back face 2.

[0060] The cell wafers use high-efficiency PERC (passivated emitter rear contact) or HJT (heterojunction) technology, and maximize the use of light energy and reduce shadow blocking effects through precise shingling design.

[0061] The cells are arranged in staggered shingles to ensure that each cell receives the maximum amount of sunlight while reducing shadow loss at the seams.

[0062] (4) Connection materials, including structural adhesive 4 and low-temperature solder 5:

[0063] Structural Adhesive 4: Does not contain silver particles. An epoxy-based heat-curing adhesive is preferred for its excellent bond strength, weather resistance, and chemical stability. The curing temperature is set at 180°C to match the heating process of most production lines.

[0064] Low-temperature solder 5: Contains 80% (by mass) silver particles. Solder paste is used as low-temperature solder 5. This solder not only contains an appropriate amount of silver to improve conductivity, but also has a curing temperature similar to that of structural adhesive, set at 180°C, to facilitate simultaneous curing and reduce production cycle time.

[0065] Structural adhesive 4 and low-temperature solder 5: Low-temperature solder 5 is arranged at the key connection points of the battery chip in the form of steel screen printing to ensure high conductivity; structural adhesive 4 is wrapped around the solder joints of the low-temperature solder in a dispensing manner to provide additional mechanical support and sealing effect.

[0066] (5) Back silver 3, front busbar 6: The front busbar 6 (busbar) plays the role of collecting carriers. The main function of the busbar is to capture photogenerated carriers, but the number and width of the busbars need to be optimized to ensure that enough carriers are collected while minimizing the obstruction of sunlight. During the design, it is necessary to find a balance between collection efficiency and light loss.

[0067] The backside of the cell wafer is not subject to lighting issues and is typically designed with an all-aluminum backside field to facilitate carrier conduction. The backside silver layer forms an electrode on the backside, which, together with the all-aluminum backside field, constitutes the backside electrode system. Both the busbar and the backside silver layer are designed to conduct carriers during the welding process. On the encapsulated cell wafer, a solder strip is welded to the busbar, and corresponding solder points are also installed on the backside to conduct current.

[0068] Example 2:

[0069] This embodiment provides a method for preparing a shingled assembly, the steps comprising:

[0070] S1. Pretreatment: Print low-temperature solder - solder paste at the corresponding position of the front electrode of the battery chip, ensuring that the solder paste printing width is 150% of the main grid line width and the thickness is controlled at 30-40um.

[0071] At the same time, structural glue is applied to the corresponding positions of other stacking areas on the back of the battery chip. The glue thickness is also controlled at 30-40um, and the glue application area is as large as 2-3 times or more of the main grid line width to cover all overlapping areas except the solder paste area.

[0072] Note that the solder paste printing area on the front should be staggered with the glue dispensing area on the back to avoid mutual influence.

[0073] S2. Stacking the battery chips: According to the design requirements, stack the battery chips one by one, ensuring that the back side of the first end of the subsequent battery chip covers and connects to the front side of the tail end of the previous battery chip.

[0074] During the stacking process, low-temperature solder paste is in direct contact with the front main grid line 6 and the back silver 3 to achieve electrical connection; while the structural glue is distributed around the electrodes or other overlapping areas to enhance the connection strength between the battery chips.

[0075] S3. Curing and connection: Heat and cure at 180°C to solidify the structural adhesive, thereby achieving mechanical connection strength between the battery chips.

[0076] At the same time, the low-temperature solder paste reacts with the front main grid line 6 and the back silver 3 to form a stable electrical connection, ensuring that the current can be transmitted smoothly.

[0077] S4. Subsequent processing: After the battery chips are stacked and solidified, subsequent electrical connection work is carried out, such as welding bus bars and electrode lead wires.

[0078] Finally, the whole package is carried out, the back film and photovoltaic back sheet are laid, and the various layers of materials are tightly bonded into a whole photovoltaic module through the lamination process, such as Figure 1 shown.

[0079] S5. Installation and testing: Install junction boxes and component frames on photovoltaic modules to protect internal circuits and facilitate connection with external systems.

[0080] Necessary performance tests and quality control checks are then carried out to ensure that the PV modules meet the design requirements and have stable power generation capabilities.

[0081] Example 3:

[0082] This embodiment provides a method for preparing a shingled assembly, the steps comprising:

[0083] S1. Printing solder paste: Print low-temperature solder paste on the corresponding position of the electrode on the back of the battery chip to ensure that the solder paste is directly connected to the positive and back electrodes. The printing area accounts for 10%-20% of the electrode area and the thickness is controlled at 30-40um.

[0084] S2. Structural adhesive dispensing: Apply regular fixed structural adhesive to the corresponding positions of other stacking areas on the front of the battery chip. Be careful to stagger the position of the printed solder paste on the back. The dispensing area should be 2-3 times or more of the electrode area to cover all overlapping areas except the solder paste area. The glue thickness should be controlled at 35-45um.

[0085] S3. Cell Stacking: According to the design requirements, stack the cell chips one by one, ensuring that the connection portion of each cell chip overlaps the corresponding position of the previous cell chip. During stacking, low-temperature solder paste contacts the front and back electrodes, while structural adhesive is applied around the front busbar 6, back silver 3, and other overlapping areas.

[0086] S4, Curing and Connecting: A 180°C heating process solidifies the structural adhesive, strengthening the connection strength between the cell chips. Simultaneously, the low-temperature solder paste alloys with the front busbars (6) and back silver (3), achieving electrical connection between the front and back electrodes.

[0087] S5. Subsequent processing: After the cell chips are stacked and cured, subsequent electrical connections are made, such as welding busbars and electrode leads. This is followed by overall packaging, laying the necessary protective layers and backsheet, and laminating the various layers to form a single, integrated photovoltaic module.

[0088] S6. Installation and testing: Install junction boxes and frames on PV modules, and conduct necessary performance tests and quality inspections to ensure that the PV modules meet design requirements and have stable power generation capabilities.

[0089] Example 4:

[0090] This embodiment provides a method for preparing a shingled assembly, the steps comprising:

[0091] S1, preparation stage: Print low-temperature solder - tin paste on the corresponding position of the back silver 3 of the battery chip, ensuring that the tin paste is directly connected to the front and back electrodes, with a width of 150% of the width of the back silver 3 and a thickness of 30-40um.

[0092] Then, apply structural glue at the corresponding positions of other stacking areas on the back of the battery chip, staggered with the solder paste position, with a glue thickness of 35-40um, and an area as large as 2-3 times that of the electrode or covering all overlapping areas except the solder paste.

[0093] S2. Battery chip processing: After ensuring that the solder paste and structural adhesive are evenly distributed, prepare to stack the battery chips.

[0094] S3. Stacking of battery chips: According to the design, stack the battery chips one by one, ensuring that the low-temperature solder paste is in contact with the front main grid line 6 and the back silver 3, and the structural glue is distributed around the electrodes or in the overlapping area to enhance the connection strength.

[0095] S4, Curing and Connecting: A 180°C heating process solidifies the structural adhesive, strengthening the physical connection between the battery chips. Simultaneously, the low-temperature solder paste alloys with the front and back silver electrodes to achieve electrical connection.

[0096] S5. Subsequent assembly: After stacking and curing, subsequent electrical connections and overall packaging are carried out, including welding bus bars and lead wires, and laying protective layers and backplanes.

[0097] S6. Testing and installation: Carry out performance testing and quality inspection on the assembled photovoltaic modules to ensure that they meet the requirements. Then install the junction boxes and frames and prepare them for use.

[0098] In summary, Examples 1-4 provide a shingled assembly that uses a combination of a conductive connection material (low-temperature solder) and a conventional fixed structural adhesive to replace the conductive adhesive. The low-temperature solder serves as the functional material for the electrical connection of the battery cells to achieve carrier transmission; while the conventional fixed structural adhesive serves as the core material for fixing the mechanical structure of the shingled assembly. The conductive connection material can be flexibly arranged in different layouts to form a stable electrical connection with the front and rear cells, thereby improving the strength and reliability of the connection between the shingled assembly sheets and increasing the power of the shingled assembly. This utility model reduces the use of low-temperature solder, effectively reduces the consumption of precious metals, further reduces the cost per kilowatt-hour, maintains the electrical characteristics of the original shingled assembly, and further improves the structural stability and electrical performance stability of the shingled assembly.

[0099] The specific embodiments of the present application have been described in detail above, but these are merely examples, and the present application is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the present application are also within the scope of the present invention. Therefore, equivalent changes and modifications made without departing from the spirit and scope of the present application should be included within the scope of the present invention.

Claims

1. A shingled assembly, characterized in that: include: Photovoltaic ultra-clear glass, photovoltaic backsheet; Multiple battery strings are composed of multiple battery cells connected in series in a shingled manner. A first adhesive film layer is provided between one side of the cell string and the photovoltaic ultra-white glass, and a second adhesive film layer is provided between the other side of the cell string and the photovoltaic backsheet; The front side of the battery chip is provided with a main grid line, and the back side is printed with back silver; joining materials, including structural adhesives and low-temperature solders; The connecting material is applied between two adjacent battery chips, front and back, to connect the battery chips and form a series circuit.

2. The shingled assembly according to claim 1, wherein: The low-temperature solder is arranged on the main grid lines of the lower battery slices.

3. The shingled assembly according to claim 1, wherein: The curing temperature of the structural adhesive is 100-180°C.

4. The shingled assembly according to claim 1, wherein: The curing temperature of the low-temperature solder is 100-180°C.

5. The shingled assembly according to claim 1, wherein: The adhesive strip formed after the low-temperature solder is solidified contains 60-80% of silver.

6. The shingled assembly according to claim 1, wherein: The structural adhesive is arranged between two low-temperature solder joints, or on one side of a low-temperature solder joint.

7. The shingled assembly according to claim 1, wherein: The structural adhesive has the same thermal curing temperature as the low-temperature solder and can be cured in one go under the same curing conditions.

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