A battery assembly step-lamination curing method

Abstract

This application provides a step-by-step lamination and curing method for battery modules, relating to the field of photovoltaic module manufacturing technology. The method includes: S1, stacking a panel, front encapsulating film, battery cell strings, back encapsulating film, and backsheet, and placing them into a laminator chamber; S2, evacuating the chamber to remove interlayer air, gradually heating the chamber to a pre-lamination temperature, then gradually applying pressure to a pre-lamination pressure, and maintaining pressure and temperature for a constant pre-lamination time at the pre-lamination temperature and pressure; S3, in the first stage, heating at a controlled rate to the film flow temperature, setting a constant temperature time according to functional area differences, allowing the film to flow and fill the electrode gaps; in the second stage, heating according to functional area differences to the crosslinking curing temperature, simultaneously maintaining constant temperature and pressure, controlling the crosslinking state of each area to a predetermined degree; S4, reducing pressure to ambient pressure in multiple stages, maintaining pressure for a preset time after each stage of pressure reduction, and simultaneously controlling the cooling rate. This method aims to improve the yield of mass-produced products.

Description

Technical Field

[0001] This application relates to the field of photovoltaic module manufacturing technology, and in particular to a step-by-step lamination and curing method for battery modules. Background Technology

[0002] Back-contact (BC) solar modules, with their unobstructed front-side grid design, improve optical utilization and electrical conversion efficiency, representing a core technology direction for high-efficiency photovoltaic modules. In BC modules, all electrodes and interconnect ribbons are concentrated on the back of the cell, forming a high-density, fine-pitch pad and raised ribbon structure. While this design improves module efficiency, it places extremely high demands on the lamination and encapsulation process.

[0003] Existing lamination processes require the adhesive film to be tightly bonded to the battery cell under high temperature and pressure, while ensuring precise placement of the solder strip, uniform cross-linking of the adhesive film, and no bubbles or debonding defects at the interface.

[0004] However, the complex structure on the back of the BC module makes the solder strips prone to shifting during the heating and pressurization stages, resulting in poor soldering or short circuits, which reduces the mass production yield of the product. Summary of the Invention

[0005] This application provides a step-by-step lamination and curing method for battery modules, which aims to improve the yield of mass production products.

[0006] This application provides a step-by-step lamination and curing method for battery modules, including the following steps:

[0007] S1. Lamination: The panel, front sealing film, battery cell string, back sealing film and backsheet are laminated and then placed into the laminator chamber.

[0008] S2, Pre-bonding: The chamber is evacuated to remove interlayer air, the chamber is gradually heated to the pre-bonding temperature, and then pressure is gradually applied to the pre-bonding pressure. The pressure is maintained at the pre-bonding temperature and the pre-bonding pressure for a constant temperature pre-bonding time, so that the encapsulating film is slightly melted, the solder ribbon and the solder pad are pre-fixed, and the initial bonding is achieved.

[0009] S3. Curing: Curing is divided into at least two stages. In the first stage, the temperature is increased to the flow temperature of the adhesive film at a controlled rate, and the constant temperature time is set according to the functional area differences to allow the adhesive film to flow and fill the electrode gap. In the second stage, the temperature is increased to the crosslinking curing temperature according to the functional area differences, and the constant temperature and pressure are maintained simultaneously to control the crosslinking state of each area to the predetermined degree.

[0010] S4. Gradient depressurization: The pressure is reduced to normal pressure in multiple stages. After each stage of depressurization, the pressure is held for a preset time, and the cooling rate is controlled simultaneously.

[0011] S5. Cooling and Discharging: After depressurization, continue cooling to a safe temperature and remove the battery components.

[0012] In one possible implementation, in step S1, the laminator chamber includes at least 12 independent temperature control zones, the number of zones corresponding to the number of functional areas on the back of the battery cell string, and each zone is configured with a temperature measurement point with a temperature measurement accuracy of less than or equal to 0.2°C.

[0013] In one possible implementation, in step S2, the pre-bonding temperature is Tpre. ℃; where Tm is the melting temperature of the front or back encapsulation film, 30℃≤A≤40℃;

[0014] The pre-bonding pressure is 0.05-0.1 MPa;

[0015] The pre-bonding time is tpre. , where k1 is the flow coefficient of the adhesive film and L is the long side dimension of the battery module.

[0016] In one possible implementation, step S3 solidifies the first stage.

[0017] The flow temperature of the adhesive film is T1, where T1 = Tm - B℃, and 10℃ ≤ B ≤ 15℃.

[0018] The isothermal time t1 = k2 × ρ, where k2 is the electrode adaptation coefficient, k2 = 1.2~1.5 for the solder ribbon interconnection area of ​​the battery cell string, k2 = 0.8~1.0 for the active area of ​​the battery cell string, k2 = 1.0~1.2 for the module edge area of ​​the battery cell string, and ρ is the electrode density.

[0019] In one possible implementation, during the first curing stage in step S3, the heating rate of the solder strip interconnection area of ​​the battery cell string is 2°C / s, the heating rate of the active area of ​​the battery cell string is 3°C / s, and the heating rate of the component edge area of ​​the battery cell string is 2~3°C / s.

[0020] In one possible implementation, during the second curing stage in step S3...

[0021] The cross-linking temperature of the solder strip interconnection area of ​​the battery cell string is T2=Tc+C℃; the cross-linking temperature of the active area of ​​the battery cell string is T2=Tc; the cross-linking temperature of the module edge area of ​​the battery cell string is T2=Tc+D℃.

[0022] Where Tc is the optimal crosslinking temperature of the front or back encapsulation film; 1℃≤C≤2℃; 2℃≤D≤3℃.

[0023] In one possible implementation, during the second curing stage in step S3, the isothermal time t2 = k3 × δ, where k3 is the crosslinking coefficient and δ is the thickness of the front or back encapsulation film.

[0024] In one possible implementation, during the second curing stage in step S3, when the degree of crosslinking C(t) of the adhesive film in any zone reaches 85%~90%, heating of that zone is stopped, and the process is switched to a heat preservation state, so that the deviation of the degree of crosslinking of the adhesive film across the entire area is less than or equal to 5%; wherein... , ,

[0025] C(t) represents the degree of crosslinking of the film at time t, k0 represents the pre-exponential factor of the film, Ea represents the activation energy of crosslinking of the film, R represents the gas constant, and T represents the real-time absolute temperature of the partition.

[0026] In one possible implementation, step S4 involves a three-stage pressure relief process: the first stage involves depressurizing to 0.15~0.2MPa at a rate less than or equal to 0.01MPa / s, and maintaining the pressure for 30~60s after the first stage of pressure relief; the second stage involves depressurizing to 0.08~0.1MPa at a rate less than or equal to 0.008MPa / s, and maintaining the pressure for 40~80s after the second stage of pressure relief; and the third stage involves depressurizing to atmospheric pressure at a rate less than or equal to 0.005MPa / s.

[0027] In one possible implementation, in step S4, gradient cooling is performed simultaneously during the depressurization process, with a cooling rate of 2~3℃ / s.

[0028] The step-by-step lamination and curing method for battery modules provided in this application achieves pre-stabilization of key internal connection structures by adding a pre-bonding process before the formal curing reaction. In step S2, by controlling the vacuum level, heating rate, and pre-bonding temperature, the encapsulating films on the front and back sides reach a slightly molten state, thereby initially bonding and positioning the solder ribbons and pads on the battery cell string without causing excessive flow of the encapsulating film. This effectively suppresses the lateral or longitudinal displacement of the solder ribbons caused by surface tension or external force disturbance when the encapsulating film is fully melted and flowed in the subsequent curing stage, reducing fatal defects such as poor soldering, poor contact, and even electrical short circuits caused by electrical connection position deviations. In addition, the combination of staged temperature and pressure control strategies ensures the uniformity and density of the encapsulating film during the filling of electrode gaps and cross-linking curing process. This significantly improves the mass production yield and long-term reliability of photovoltaic battery modules. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0030] Figure 1 This is a schematic diagram of the step-by-step lamination and curing method for battery modules provided in this application.

[0031] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0032] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0033] In back-contact (BC) solar modules, all electrodes and interconnecting ribbons are concentrated on the back of the cell, forming a high-density, fine-pitch pad and raised ribbon structure. While this design improves module efficiency, it places extremely high demands on the lamination process. Existing lamination processes require achieving tight adhesion between the encapsulant film and the cell under high temperature and pressure, while ensuring precise ribbon positioning, uniform cross-linking of the encapsulant film, and the absence of bubbles or debonding defects at the interface. However, the complex structure on the back of the BC module makes the ribbons prone to misalignment during the heating and pressurization stages, resulting in poor soldering or short circuits, thus reducing the mass production yield.

[0034] The step-by-step lamination and curing method for solar modules provided in this application achieves pre-stabilization of critical internal connection structures by adding a pre-bonding process before the formal curing reaction. In step S2, by controlling the vacuum level, heating rate, and pre-bonding temperature, the encapsulating films on the front and back sides are brought to a slightly molten state, thereby initially bonding and positioning the solder ribbons and pads on the cell strings without causing excessive flow of the encapsulating film. This effectively suppresses lateral or longitudinal displacement of the solder ribbons caused by surface tension or external force disturbance when the encapsulating film is fully melted and flowed in the subsequent curing stage, reducing fatal defects such as poor soldering, poor contact, and even electrical short circuits caused by electrical connection position deviations. In addition, the combination of staged temperature and pressure control strategies ensures the uniformity and density of the encapsulating film during the filling of electrode gaps and cross-linking curing process. This significantly improves the mass production yield and long-term reliability of photovoltaic cell modules.

[0035] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0036] This application provides a step-by-step lamination and curing method for battery components, referring to... Figure 1 The step-by-step lamination and curing method for battery components includes the following steps:

[0037] S1. Lamination: The panel, front sealing film, battery cell string, back sealing film and backsheet are laminated and placed into the laminator chamber.

[0038] S2. Pre-bonding: The chamber is evacuated to remove interlayer air, the chamber is gradually heated to the pre-bonding temperature, and then pressure is gradually applied to the pre-bonding pressure. The pressure is maintained at the pre-bonding temperature and pressure for a constant pre-bonding time, so that the encapsulation film is slightly melted, the solder ribbon and the pad are pre-fixed, and the initial bonding is achieved.

[0039] S3. Curing: Curing is divided into at least two stages. In the first stage, the temperature is increased to the flow temperature of the adhesive film at a controlled rate, and the constant temperature time is set according to the functional area differences to allow the adhesive film to flow and fill the electrode gap. In the second stage, the temperature is increased to the cross-linking curing temperature according to the functional area differences, and the constant temperature and pressure are maintained simultaneously to control the cross-linking state of each area to the predetermined degree.

[0040] S4. Gradient pressure relief: The pressure is reduced to normal pressure in multiple stages. After each stage of pressure relief, the pressure is held for a preset time, and the cooling rate is controlled simultaneously.

[0041] S5. Cooling and Discharging: After depressurization, continue cooling to a safe temperature and remove the battery components.

[0042] By adding a pre-bonding process before the formal curing reaction, the encapsulating film is slightly dissolved under controlled temperature in a vacuum environment, achieving high-precision pre-fixation of the BC module solder ribbon. This effectively suppresses solder ribbon misalignment caused by film flow in subsequent processes, thus solving problems such as cold solder joints and short circuits. Simultaneously, the curing process is divided into at least two stages, with temperature and isothermal time set differently according to functional areas, ensuring uniform and controllable cross-linking reaction of the film and reducing defects such as uneven cross-linking, bubbles, and debonding. Regarding venting, vacuum evacuation and gradient pressure relief processes in the pre-bonding stage ensure sufficient removal of interlayer gases. Furthermore, precise control of temperature, pressure, and time parameters at each stage reduces thermal and mechanical stress on the back electrode and passivation layer, achieving low-damage lamination. The parameters of the entire process can be automatically adapted and adjusted according to different product requirements, improving the flexibility and adaptability of the process. This, in turn, improves the mass production yield and long-term reliability of BC battery modules.

[0043] The back-contact solar module consists of a panel, a front encapsulating film, a cell string, a back encapsulating film, and a backsheet, stacked sequentially from front to back. The panel is made of photovoltaic glass. The back of the cell string is divided into three core areas: a solder ribbon interconnection area, a cell active area, and a module edge area. The laminator heating plate adopts a 12-zone independent temperature control architecture, with each zone corresponding to a functional area.

[0044] The solder ribbon interconnection area is the region where the solder ribbon overlaps with the electrode pads. It has the highest electrode density and the most stringent requirements for temperature uniformity and solder ribbon positioning. The active cell area is the active area on the back of the cell without solder ribbons, and it requires high uniformity of cross-linking. The module edge area is the edge sealing area of ​​the module, which dissipates heat quickly and requires temperature compensation to ensure effective cross-linking.

[0045] In one possible implementation, in step S1, the laminator chamber includes at least 12 independent temperature control zones, the number of zones corresponding to the number of functional areas on the back of the battery cell string, and each zone is configured with a temperature measurement point with a temperature measurement accuracy of less than or equal to 0.2°C.

[0046] By setting temperature control zones and functional areas accordingly, and combining them with high-precision temperature measurement points, it is possible to perceive and independently control the temperature of different areas of the battery module. This provides data support and execution basis for subsequent differentiated temperature increases in different areas, avoids inconsistent curing of the adhesive film due to uneven temperature distribution, and effectively improves the accuracy and uniformity of temperature control during lamination. This ensures the consistency of cross-linking state in each area of ​​the module and improves product yield and reliability.

[0047] Furthermore, in step S1, it is also necessary to output the basic parameters of the battery module. These basic parameters include, but are not limited to, battery type, electrode density ρ, solder ribbon specifications, silicon wafer thickness, encapsulating film type, encapsulating film melting temperature Tm, optimal crosslinking temperature Tc, and module long side dimension L. The parameters for the corresponding pre-lamination and curing steps are then calculated based on these basic parameters.

[0048] In one possible implementation, in step S2, the pre-bonding temperature is Tpre. ℃; where Tm is the melting temperature of the front or back encapsulation film, 30℃≤A≤40℃;

[0049] The pre-bonding pressure is 0.05-0.1 MPa;

[0050] The pre-bonding time is tpre. , where k1 is the flow coefficient of the adhesive film and L is the long side dimension of the battery module.

[0051] For example, the pre-bonding temperature is 80℃≤Tpre≤100℃.

[0052] In polyolefin elastomer (POE) films, k1 = 15~20 s / m. In ethylene-vinyl acetate copolymer (EVA / co-extruded EVA) films, k1 = 10~15 s / m.

[0053] This parameter combination allows the adhesive film to flow fully within the module and achieve initial adhesion, forming a stable physical bond. This provides a uniform interlayer distribution foundation for subsequent lamination and curing, effectively reducing the risk of air bubbles and delamination within the module. It also enables pre-fixation of the solder ribbons in the BC module, effectively suppressing ribbon misalignment caused by adhesive film flow in subsequent processes, thereby resolving issues such as incomplete soldering and short circuits.

[0054] For example, in step S2, the chamber is evacuated to remove interlayer air. Specifically, the laminator chamber is closed, the vacuum is turned on, the vacuum degree is controlled at -95~-100kPa, the vacuum time is 200~300s, and the interlayer air is completely removed.

[0055] Subsequently, while maintaining the vacuum level of the chamber, all temperature-controlled zones of the laminator are simultaneously heated to the pre-lamination temperature Tpre calculated in step S1 at a heating rate of 3°C / s to 5°C / s. This heating rate can effectively prevent the encapsulating film from melting prematurely due to excessive temperature rise.

[0056] Next, once the chamber temperature reaches the pre-bonding temperature Tpre, it is kept constant, and the pre-bonding pressure Ppre is slowly applied at this temperature while maintaining a constant temperature and pressure. The pressure holding time is the pre-bonding time tpre calculated in step S1.

[0057] This allows the encapsulating film to be in a slightly molten state at this temperature, where it exhibits only slight tackiness without significant flow. This state pre-fixes the solder ribbon to the electrode pads of the solar cell, reducing solder ribbon misalignment during subsequent heating and pressurization, and also helps to eliminate residual micro-bubbles between layers. Simultaneously, because a low-pressure condition is applied, it avoids pressure damage to the passivation layer on the back of the solar cell.

[0058] In one possible implementation, step S3 solidifies the first stage.

[0059] The flow temperature of the adhesive film is T1, where T1 = Tm - B℃, and 10℃ ≤ B ≤ 15℃.

[0060] The isothermal time t1 = k2 × ρ, where k2 is the electrode adaptation coefficient, k2 = 1.2~1.5 for the solder ribbon interconnection area of ​​the cell string, k2 = 0.8~1.0 for the active cell area of ​​the cell string, k2 = 1.0~1.2 for the module edge area of ​​the cell string, and ρ is the electrode density.

[0061] For example, the film flow temperature T1 is the constant temperature during this process. The range of the film flow temperature is 110℃≤T1≤120℃.

[0062] In one possible implementation, during the first curing stage in step S3, the heating rate of the solder strip interconnection area of ​​the cell string is 2°C / s, the heating rate of the active cell area of ​​the cell string is 3°C / s, and the heating rate of the module edge area of ​​the cell string is 2~3°C / s.

[0063] By controlling the heating rate in zones, precise regulation of the temperature field is achieved, ensuring that the active area of ​​the battery quickly reaches the curing temperature to improve reaction efficiency. At the same time, the heating of the solder ribbon interconnection area is more uniform and gentle, effectively avoiding the risk of solder ribbon failure, misalignment, or microcracks in the battery cell caused by thermal stress concentration. In addition, the gradient heating strategy also helps the encapsulant film to achieve initial cross-linking in different areas simultaneously, improving the overall curing consistency and structural reliability of the module.

[0064] In one possible implementation, during the second curing stage in step S3...

[0065] The cross-linking temperature of the solder ribbon interconnection zone of the cell string is T2 = Tc + C℃; the cross-linking temperature of the active cell zone of the cell string is T2 = Tc; the cross-linking temperature of the module edge zone of the cell string is T2 = Tc + D℃.

[0066] Where Tc is the optimal crosslinking temperature of the front or back encapsulation film; 1℃≤C≤2℃; 2℃≤D≤3℃.

[0067] Leveraging the excellent thermal conductivity of the solder ribbon metal, the cross-linking of the encapsulant film in the solder ribbon region is accelerated at a temperature slightly above the optimal cross-linking temperature (Tc), ensuring a strong bond between the solder ribbon and the electrode. Maintaining the active area of ​​the cell at the optimal cross-linking temperature Tc ensures sufficient cross-linking of the encapsulant film to provide excellent electrical insulation and mechanical support, while preventing cell efficiency degradation due to overheating. A higher temperature (Tc+D℃) is set at the edge of the module to compensate for the temperature gradient caused by edge heat dissipation, preventing insufficient cross-linking of the encapsulant film at the edges. This effectively balances the curing rates of different areas, eliminating internal stress concentration caused by uneven temperature, preventing defects such as module warping and delamination, and significantly improving the reliability of the solder ribbon connection, the protection effect of the cells, and the overall long-term weather resistance of the module.

[0068] In one possible implementation, during the second curing stage in step S3, the isothermal time t2 = k3 × δ, where k3 is the crosslinking coefficient and δ is the thickness of the front or back encapsulation film.

[0069] Wherein, k3 = 1-1.2 s / μm for POE film, k3 = 0.8-1.0 s / μm for EVA film, and δ is the film thickness. In the example of this application, the value of k3 ranges from 400 to 600 s.

[0070] In one possible implementation, during the second curing stage in step S3, when the degree of crosslinking C(t) of the adhesive film in any zone reaches 85%~90%, heating of that zone is stopped, and the process is switched to a heat preservation state, so that the deviation of the degree of crosslinking of the adhesive film across the entire area is less than or equal to 5%; wherein... , ,

[0071] C(t) represents the degree of crosslinking of the film at time t, k0 represents the pre-exponential factor of the film, Ea represents the activation energy of crosslinking of the film, R represents the gas constant, and T represents the real-time absolute temperature of the partition.

[0072] Specifically, in step S3, after pre-bonding is completed, the chamber vacuum and pre-bonding pressure are maintained, and the heating and curing are completed in two stages, with differentiated temperature control for each zone throughout the process. The first stage is a constant temperature process for film flow filling, in which each zone is heated to T1 at a heating rate of 2~3℃ / s. The heating rate of the solder ribbon interconnection zone is controlled at 2℃ / s to avoid thermal deformation of the solder ribbon, and the heating rate of the battery active zone is controlled at 3℃ / s.

[0073] After heating to T1, differential temperature control is performed according to the preset t1. The temperature control in the solder ribbon interconnection area is 120~180s, the temperature control in the active cell area is 80~120s, and the temperature control in the module edge area is 100~150s. This temperature is the initial melting temperature of the adhesive film. The adhesive film flows slowly. The differential temperature control time can ensure that the adhesive film in the raised area of ​​the solder ribbon fully fills the electrode gap, wets the interface between the solder ribbon and the pad, avoids the appearance of interface voids after subsequent cross-linking, and prevents the solder ribbon from shifting due to excessive flow.

[0074] The second stage is a zoned differentiated crosslinking and curing process. Each zone is heated to the differentiated crosslinking temperature T2 at a heating rate of 1~2℃ / s to ensure that the entire film enters the optimal crosslinking state simultaneously. After heating to T2, the temperature is kept constant and the lamination pressure is increased to 0.2~0.3MPa for a holding time of t2. During the holding process, the crosslinking state of each zone is controlled in a closed loop using a crosslinking degree calculation formula. When the model predicts that the crosslinking degree of a certain zone reaches 85%~90%, the heating of that zone is automatically stopped and the temperature is kept constant, ultimately ensuring that the crosslinking degree deviation of the entire film does not exceed 5%.

[0075] During the constant temperature process, an adaptive PID algorithm is used to adjust the heating power of each zone in real time, and the temperature control accuracy is controlled within ±0.5℃.

[0076] It achieves precise control of film flow filling and cross-linking curing, effectively avoiding defects such as solder strip misalignment, interface voids and uneven cross-linking degree, and significantly improving the encapsulation reliability and long-term stability of the components.

[0077] In one possible implementation, step S4 involves a three-stage pressure relief process: the first stage involves depressurizing to 0.15~0.2MPa at a rate less than or equal to 0.01MPa / s, and maintaining the pressure for 30~60s after the first stage of pressure relief; the second stage involves depressurizing to 0.08~0.1MPa at a rate less than or equal to 0.008MPa / s, and maintaining the pressure for 40~80s after the second stage of pressure relief; and the third stage involves depressurizing to atmospheric pressure at a rate less than or equal to 0.005MPa / s.

[0078] By employing a three-stage gradient depressurization process, which utilizes a progressively decreasing depressurization rate combined with a pressure holding period in the middle stage, the generation of microbubbles or "flash evaporation" inside the encapsulant film caused by a sudden drop in pressure is effectively avoided. At the same time, the pressure holding window period is used to allow the small molecule gas remaining in the encapsulant film to escape fully and gradually release the interfacial stress between the electrode and the encapsulant film. Ultimately, while ensuring the tightness of the module encapsulation, it prevents interlayer debonding or structural damage caused by rapid depressurization, thereby improving the encapsulation quality and long-term reliability of the module.

[0079] In one possible implementation, in step S4, gradient cooling is performed simultaneously during the depressurization process, with a cooling rate of 2~3℃ / s.

[0080] Specifically, in step S4, after the cross-linking isothermal process is completed, heating is stopped, and the pressure relief and holding process begins. Throughout this process, the chamber temperature is maintained at no less than 100°C to prevent premature cooling and embrittlement of the adhesive film. A three-stage gradient pressure relief is employed to prevent sudden pressure drops that could cause air bubbles to form inside the adhesive film, while simultaneously releasing interfacial stress. The first stage of pressure relief reduces the pressure from 0.2~0.3MPa to 0.15~0.2MPa at a rate not exceeding 0.01MPa / s, and holds the pressure for 30~60s after relief, allowing small molecule gases to slowly escape from the adhesive film. The second stage of pressure relief reduces the pressure to 0.08~0.1MPa at a rate not exceeding 0.008MPa / s, and holds the pressure for 40~80s, releasing interfacial stress between the electrode and the adhesive film. The third stage of pressure relief reduces the pressure to atmospheric pressure at a rate not exceeding 0.005MPa / s, with no sudden pressure drops throughout the process. Gradual cooling is performed simultaneously during the depressurization process, with the cooling rate controlled at 2~3℃ / s to avoid interfacial thermal stress debonding and passivation layer damage caused by rapid cooling.

[0081] Example 1 provides a step-by-step lamination method for a 210mm large-size TOPConBC single-glass module.

[0082] Among them, the battery module is a 210mm-78mm TOPConBC single-glass module with a 12-busbar design, a back electrode density of 12 electrodes / cm, a silicon wafer thickness of 150μm, and a mass production conversion efficiency of up to 25.8%.

[0083] The stacked structure, from front to back, consists of: 3.2mm tempered glass (panel), 500μm POE film (front encapsulation film), BC battery string, 500μm POE film (back encapsulation film), and TPT composite backplane (backplane).

[0084] The key parameters of the POE film used are as follows: melt temperature Tm is 120℃, optimal crosslinking temperature Tc is 135℃, film activation energy Ea is 85kJ / mol, and pre-exponential factor k0 is 1.2×10⁻⁶. 6 s⁻¹; The long side dimension L of the component is 2.384m.

[0085] S1, Layering:

[0086] Following the above-mentioned stacked structure, 3.2mm tempered glass, 500μm POE front encapsulation film, BC battery cell string, 500μm POE back encapsulation film and TPT composite backsheet are stacked in sequence to ensure that each layer is aligned, without offset or impurities. After the stacking is completed, the entire structure is placed smoothly into the laminator chamber and the chamber door is closed to prepare for subsequent processes.

[0087] S2, Pre-lamination:

[0088] The laminator chamber is evacuated to completely remove air between the layers and prevent air bubbles from forming after lamination. The vacuum level is controlled at -98 kPa and the evacuation time is 280 seconds. The evacuation operation is performed uniformly throughout the entire chamber.

[0089] After vacuuming, the chamber is gradually heated to the pre-bonding temperature of 85°C at a heating rate of 3°C / s, and then gradually pressurized to the pre-bonding pressure of 0.08MPa. The chamber is then held at this pre-bonding temperature and pressure for 45s. In this step, all zones of the chamber use the same temperature and pressure parameters to slightly dissolve the POE encapsulation film, thereby pre-fixing the solder ribbon and pads and completing the initial bonding of each layer, laying the foundation for the subsequent curing process.

[0090] S3. Curing:

[0091] This step divides the curing process into two stages, setting process parameters according to the differences in functional areas to ensure that the adhesive film flows and fills fully and cross-links and cures evenly:

[0092] The first stage (flow and filling stage): The temperature is increased to the film flow temperature of 110℃ at a controlled rate of 2℃ / s (lower than the POE film melting temperature Tm=120℃, to ensure film flow and prevent over-melting). The isothermal time is set differently according to functional areas, with the solder ribbon interconnect area being isothermal for 150s, the active area of ​​the cell being isothermal for 100s, and the edge area being isothermal for 120s. Through differentiated isothermal control, the film is allowed to flow fully and fill the gaps between electrodes and between the solder ribbon and the silicon wafer, avoiding defects such as voids and missing adhesive.

[0093] The second stage (crosslinking and curing stage): The temperature is increased to the crosslinking and curing temperature at a rate of 1.5℃ / s according to the functional areas, while maintaining the lamination pressure at 0.25MPa and simultaneously holding the temperature and pressure at a constant temperature to control the crosslinking state of each area to the predetermined degree. The specific parameters are: the solder ribbon interconnect area is heated to 136℃ and held for 500s, the active area of ​​the battery is heated to 135℃ and held for 500s, and the edge area is heated to 137℃ and held for 500s. This differentiated temperature setting is adapted to the heat dissipation characteristics of each functional area to ensure uniform crosslinking of the entire component.

[0094] S4, Gradient pressure relief:

[0095] After cross-linking and curing are completed, the gradient depressurization process begins. Throughout this process, the chamber temperature is maintained at no less than 100℃ to prevent stress, microcracks, and other defects in the components caused by sudden temperature drops. The total depressurization time is 320 seconds, with the pressure reduced to atmospheric pressure in three stages. Each stage of depressurization is followed by a preset holding time. The specific steps are as follows:

[0096] First stage: depressurize from 0.25MPa to 0.18MPa, with the depressurization rate controlled at 0.01MPa / s, and maintain pressure for 45s after depressurization is completed;

[0097] The second stage: the pressure is released from 0.18 MPa to 0.1 MPa, the pressure release rate is controlled at 0.008 MPa / s, and the pressure is maintained for 60 seconds after the pressure release is completed;

[0098] The third stage: depressurize from 0.1 MPa to atmospheric pressure, with the depressurization rate controlled at 0.005 MPa / s to ensure a steady pressure drop and reduce internal stress in the components.

[0099] S5, Cooling and Discharging:

[0100] After the gradient depressurization is completed, the chamber continues to be cooled down at a rate of 2℃ / s to avoid thermal stress caused by excessive cooling. Once the component temperature drops to the safe discharge temperature of 45℃, the laminator chamber is opened, the battery component is removed, and the entire lamination process is completed.

[0101] Table 1 shows the test results of the 210mm large-size TOPConBC single-glass module.

[0102]

[0103] As shown in Table 1, after low-temperature pre-bonding and pre-fixing of the solder ribbon, the positioning accuracy is improved, and the offset rate of the BC module solder ribbon is reduced from 1.32% in the existing technology to below 0.1%, thereby reducing the problems of poor soldering and short circuits caused by offset. Relying on zoned differentiated temperature control and closed-loop control of crosslinking degree, the uniformity of film crosslinking has achieved a qualitative breakthrough. The crosslinking degree deviation in the whole area has been narrowed from more than 15% to less than 5%, and is stably maintained in the optimal range of 85%~90%. The rate of encapsulation defects such as lamination bubbles and debonding has been reduced from 0.8%-1.2% to below 0.1%, and the module appearance yield has been improved from 97% to more than 99.5%. Long-term reliability has been greatly enhanced. After 1000 hours of dual 85 aging, the module efficiency retention rate has increased from 95% to more than 98.5%, and the efficiency decay after PID testing is no more than 0.5%, resulting in a significant performance improvement. Meanwhile, thanks to parameter adaptive matching and strong process adaptability, it can automatically adapt to multiple types and specifications of BC components, reducing product changeover time from 2 hours to less than 10 minutes, eliminating the need for repeated manual parameter adjustments, and improving mass production efficiency.

[0104] Example 2 provides a step-by-step lamination method for a 182mm x 100μm thin-film IBC single-glass module. The cell module is a 182mm-72mm N-type IBC module with an 18-busbar design, a back electrode density of 18 electrodes / cm, a silicon wafer thickness of 100μm, and a mass production conversion efficiency of 26.2%.

[0105] The stacked structure, from front to back, consists of: 2.8mm ultra-thin tempered glass, 450μm co-extruded POE film, IBC battery string, 450μm co-extruded POE film, and KPK backplate. Each layer is tightly bonded to ensure that there are no foreign objects left between the layers.

[0106] The core parameters of the co-extruded POE film used are as follows: melt temperature Tm=115℃, optimal crosslinking temperature Tc=130℃, which is suitable for the low-temperature lamination requirements of silicon wafers and can effectively reduce the damage to silicon wafers caused by temperature shock; the long side dimension of the module L=2.278m, which is suitable for the laminator chamber specifications and ensures uniform pressure and temperature distribution during the lamination process.

[0107] S1. Lamination: Using 2.8mm ultra-thin tempered glass as the panel, 450μm co-extruded POE film (front encapsulation film), IBC cell string, 450μm co-extruded POE film (back encapsulation film), and KPK backsheet are laid in sequence. Handle with care during the lamination process to avoid touching the silicon wafer and causing fragmentation. After lamination, place it stably into the laminator chamber to ensure that the module is centered and free from offset or wrinkles.

[0108] S2. Pre-lamination: First, the laminator chamber is evacuated to a vacuum level of -99 kPa for 320 seconds. This process is performed uniformly throughout the entire chamber to ensure that air is fully expelled from between layers, preventing air bubbles after lamination. Then, the chamber is gradually heated to the pre-lamination temperature of 80°C at a gentle heating rate of 2.5°C / s, and then gradually pressurized to the pre-lamination pressure of 0.06 MPa. Under the process conditions of 80°C and 0.06 MPa, pre-lamination is performed under constant temperature and pressure for 40 seconds. Uniform temperature parameters are used throughout the entire process to allow the co-extruded POE film to slightly dissolve, achieving pre-fixation of the solder ribbon and pads, completing the initial bonding of the battery string and encapsulation material, while avoiding damage to the silicon wafer caused by sudden temperature and pressure changes.

[0109] S3. Curing: The curing process is divided into two stages: film flow and filling and cross-linking curing. Process parameters are set according to the differences in functional areas.

[0110] 1. First stage (film flow and filling): The temperature is slowly increased to the film flow temperature of 105℃ at a controlled heating rate of 1.5℃ / s (below the film melting temperature to avoid excessive film flow and impact on the silicon wafer); the isothermal time is set according to the functional area, with the solder ribbon interconnect area being isothermal for 180s, the active cell area for 120s, and the edge area for 150s, so that the co-extruded POE film flows slowly and fully fills the electrode gaps and the contact gaps between the solder ribbon and the silicon wafer, avoiding defects such as insufficient filling and voids, while reducing the impact of film flow on the silicon wafer.

[0111] 2. Second stage (crosslinking and curing): The temperature is gradually increased to the corresponding crosslinking and curing temperature according to the functional areas at a gentle heating rate of 1℃ / s, while maintaining the lamination pressure at 0.22MPa (low pressure setting to prevent microcracks in the silicon wafer caused by high pressure), and the temperature and pressure are kept constant simultaneously. The specific parameters are: 131℃ for 450s for the solder ribbon interconnect area, 130℃ for 450s for the active cell area, and 132℃ for 450s for the edge area. This ensures that the crosslinking state of the adhesive film in each functional area reaches the predetermined level, improves the bonding strength and sealing of the module, and avoids the performance degradation of the silicon wafer caused by prolonged high temperature.

[0112] S4. Gradient Depressurization: After cross-linking and curing, the gradient depressurization process begins. Throughout the process, the chamber temperature is maintained at no less than 95℃ to prevent sudden temperature drops that could lead to thermal stress concentration in the components and microcracks in the silicon wafers. The total depressurization time is 350 seconds, with pressure reduced to atmospheric pressure in three stages. Each stage of depressurization is followed by a preset pressure holding time, and the cooling rate is controlled synchronously. The specific steps are as follows:

[0113] The first stage: the pressure is released from 0.22MPa to 0.16MPa, the pressure release rate is controlled at 0.008MPa / s, and the pressure is held for 40s after the pressure release is completed, so that the components can gradually adapt to the pressure change;

[0114] The second stage involves depressurizing from 0.16 MPa to 0.09 MPa at a rate of 0.006 MPa / s, followed by holding the pressure for 50 seconds after depressurization to further release internal stress within the component.

[0115] The third stage involves depressurizing from 0.09 MPa to atmospheric pressure at a rate controlled at 0.004 MPa / s to ensure a smooth pressure transition and prevent sudden pressure drops that could lead to component deformation or silicon wafer damage.

[0116] S5. Cooling and Unloading: After the gradient depressurization is completed, the chamber continues to be cooled. The cooling rate is controlled at 1.5℃ / s (gradual cooling to reduce thermal stress). This is carried out uniformly in all zones. After the module temperature drops to the safe unloading temperature of 40℃, the laminated IBC single-glass module is smoothly removed to avoid silicon wafer fragments caused by collisions and friction during the removal process.

[0117] Table 2 shows the test results of a 182mm x 100μm thin-film IBC single-glass module.

[0118]

[0119] As shown in Table 2, Example 2 optimized the temperature and pressure parameters for the characteristics of 100μm silicon wafers, effectively controlling defects such as microcracks and fragmentation. The EL microcrack / fragmentation defect rate was only 0.02%, far lower than the 1.12% of the existing one-step process. Simultaneously, the average crosslinking degree of the encapsulant film in the module reached 86.5%, with excellent uniformity of crosslinking across the entire area (maximum deviation of only 3.8%). The solder ribbon offset rate and total lamination defect rate were both at extremely low levels. The efficiency degradation after PID testing was small, and the double 85 aging stability was strong. Compared with the existing one-step process, the module prepared in this example shows improvements in reliability, uniformity, and defect control.

[0120] Finally, it should be noted that other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and alterations may be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A step-by-step lamination and curing method for battery components, characterized in that, Includes the following steps: S1. Lamination: The panel, front sealing film, battery cell string, back sealing film and backsheet are laminated and then placed into the laminator chamber. S2, Pre-bonding: The chamber is evacuated to remove interlayer air, the chamber is gradually heated to the pre-bonding temperature, and then pressure is gradually applied to the pre-bonding pressure. The pressure is maintained at the pre-bonding temperature and the pre-bonding pressure for a constant temperature pre-bonding time, so that the encapsulating film is slightly melted, the solder ribbon and the solder pad are pre-fixed, and the initial bonding is achieved. S3. Curing: Curing is divided into at least two stages. In the first stage, the temperature is increased to the flow temperature of the adhesive film at a controlled rate, and the constant temperature time is set according to the functional area differences to allow the adhesive film to flow and fill the electrode gap. In the second stage, the temperature is increased to the crosslinking curing temperature according to the functional area differences, and the constant temperature and pressure are maintained simultaneously to control the crosslinking state of each area to the predetermined degree. S4. Gradient depressurization: The pressure is reduced to normal pressure in multiple stages. After each stage of depressurization, the pressure is held for a preset time, and the cooling rate is controlled simultaneously. S5. Cooling and Discharging: After depressurization, continue cooling to a safe temperature and remove the battery components.

2. The step-by-step lamination and curing method for battery modules according to claim 1, characterized in that, In step S1, the laminator chamber includes at least 12 independent temperature control zones, the number of zones corresponding to the number of functional areas on the back of the battery cell string, and each zone is configured with a temperature measurement point with a temperature measurement accuracy of less than or equal to 0.2℃.

3. The step-by-step lamination and curing method for battery modules according to claim 1, characterized in that, In step S2, the pre-bonding temperature is Tpre. ℃; where Tm is the melting temperature of the front or back encapsulation film, 30℃≤A≤40℃; The pre-bonding pressure is 0.05-0.1 MPa; The pre-bonding time is tpre. , where k1 is the flow coefficient of the adhesive film and L is the long side dimension of the battery module.

4. The step-by-step lamination and curing method for battery modules according to claim 1, characterized in that, In step S3, during the first stage of curing, The flow temperature of the adhesive film is T1, where T1 = Tm - B℃, and 10℃ ≤ B ≤ 15℃. Constant temperature time Wherein, k2 is the electrode adaptation coefficient, k2=1.2~1.5 for the solder strip interconnection area of ​​the battery cell string, k2=0.8~1.0 for the active area of ​​the battery cell string, k2=1.0~1.2 for the module edge area of ​​the battery cell string, and ρ is the electrode density.

5. The step-by-step lamination and curing method for battery modules according to claim 4, characterized in that, In the first curing stage of step S3, the heating rate of the solder ribbon interconnection area of ​​the battery cell string is 2℃ / s, the heating rate of the active area of ​​the battery cell string is 3℃ / s, and the heating rate of the component edge area of ​​the battery cell string is 2~3℃ / s.

6. The step-by-step lamination and curing method for battery modules according to claim 1, characterized in that, In step S3, during the second curing stage, The cross-linking temperature of the solder strip interconnection area of ​​the battery cell string is T2=Tc+C℃; the cross-linking temperature of the active area of ​​the battery cell string is T2=Tc; the cross-linking temperature of the module edge area of ​​the battery cell string is T2=Tc+D℃. Where Tc is the optimal crosslinking temperature of the front or back encapsulation film; 1℃≤C≤2℃; 2℃≤D≤3℃.

7. The step-by-step lamination and curing method for battery modules according to claim 6, characterized in that, In the second curing stage of step S3, the isothermal time t2 = k3 × δ, where k3 is the crosslinking coefficient and δ is the thickness of the front or back encapsulation film.

8. The step-by-step lamination and curing method for battery modules according to claim 7, characterized in that, In the second curing stage (S3), when the degree of crosslinking C(t) of the adhesive film in any zone reaches 85%~90%, heating of that zone is stopped, and the zone is switched to a heat preservation state to ensure that the crosslinking degree deviation of the adhesive film across the entire area is less than or equal to 5%; wherein, , , C(t) represents the degree of crosslinking of the film at time t, k0 represents the pre-exponential factor of the film, Ea represents the activation energy of crosslinking of the film, R represents the gas constant, and T represents the real-time absolute temperature of the partition.

9. The step-by-step lamination and curing method for battery modules according to claim 1, characterized in that, In step S4, the pressure is released in three stages: the first stage releases the pressure to 0.15~0.2MPa at a rate of less than or equal to 0.01MPa / s, and the pressure is maintained for 30~60s after the first stage of pressure release is completed; the second stage releases the pressure to 0.08~0.1MPa at a rate of less than or equal to 0.008MPa / s, and the pressure is maintained for 40~80s after the second stage of pressure release is completed; the third stage releases the pressure to atmospheric pressure at a rate of less than or equal to 0.005MPa / s.

10. The step-by-step lamination and curing method for battery modules according to claim 7, characterized in that, In step S4, gradient cooling is performed simultaneously during the depressurization process, with a cooling rate of 2~3℃ / s.

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