Device and method for reducing the warpage of BC battery strings

Abstract

This invention discloses a device and method for reducing the warpage of BC (Browser-Based Cell) strings, belonging to the field of photovoltaic cell processing technology. The invention employs a thermo-mechanical co-shaping scheme. The device includes a flipping and bending mechanism, an integrated automatic air blowing mechanism, and an intelligent temperature control system. The flipping and bending mechanism achieves 180° flipping of the cell string and controllable plastic correction, while simultaneously using perforated copper tubes to blow pre-cooled and dehumidified compressed air for forced cooling. This invention uses dual PID closed-loop control combined with air-temperature compensation, pressure-linked temperature control, and signal filtering feedforward compensation strategies to precisely control the cooling rate and temperature gradient of the cells, completing rapid thermal shrinkage shaping during the plastic deformation stage. This invention can eliminate residual stress inside the cell string, prevent warpage and springback, effectively avoid microcracks in the cells, achieve good correction consistency, and high production efficiency, making it suitable for large-scale, high-quality production of BC cells.

Description

Technical Field

[0001] This invention relates to the field of BC battery manufacturing and processing technology, specifically to a device and method for reducing the warping degree of BC battery strings. Background Technology

[0002] As the mainstream category of high-efficiency photovoltaic cells, the warping and deformation of BC cells after the cell strings are welded and formed during industrial production is a key pain point affecting the yield of cells and the quality of module packaging.

[0003] In the BC battery manufacturing process, the battery cells first need to undergo insulating adhesive printing and drying curing. During the curing process of the insulating adhesive, the epoxy molecules undergo irreversible thermal expansion and contraction deformation. Combined with the effect of natural gravity, the battery cells will initially form a warpage of about 1 mm towards the blue film surface. On this basis, when the BC battery cells with printed insulating adhesive and solder paste are connected to the solder ribbon for stringing, there is a significant difference in the coefficient of thermal expansion between the battery cell substrate and the metal solder ribbon. After the solder ribbon is melted at high temperature and cooled and cured, it will generate shrinkage and tensile stress, which ultimately leads to severe warpage deformation of more than 3 mm towards the blue film surface in the formed BC battery string.

[0004] Current industry solutions for BC battery string warpage rely solely on a single bending mechanism to physically flatten and correct the welded battery strings. This purely mechanical correction method has significant drawbacks: Firstly, simply using external force to forcibly correct warping deformation cannot eliminate residual thermal and structural stresses inside the solar cell. As a result, the solar cell is prone to warping and rebounding in subsequent processes, leading to poor correction effect and low stability. Secondly, the instantaneous forced pressure and flattening operation of mechanical external force can easily cause defects such as microcracks and edge breakage in thin-walled BC battery cells, which greatly reduces the yield of battery strings and increases production losses and production costs.

[0005] In summary, existing BC battery string warpage correction technologies suffer from problems such as poor correction accuracy, high rebound rate, easy generation of microcracks in battery cells, and low yield. They cannot meet the production requirements of large-scale, high-quality BC battery strings. There is an urgent need for a warpage correction technology solution that combines thermal and mechanical shaping, high precision, and low damage. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a device and method for reducing the warping degree of BC battery strings, thereby solving the technical problems of severe warping and rebound, easy generation of microcracks in battery cells, and poor correction effect of the existing pure mechanical correction method.

[0007] The technical solution of this invention is implemented as follows: An apparatus for reducing the warpage of BC battery strings, comprising: The flipping and bending mechanism is used to flip and physically correct the BC battery strings that have been welded at high temperature. The flipping and bending mechanism includes a profile support, string-picking suction cups and bending pressure blocks on both sides of the profile support, and a rotary cylinder that drives the profile support to rotate. The string-picking suction cups are used to pick up the middle area of ​​the battery string, and the bending pressure blocks are used to apply downward pressure during the flipping process to correct the warping of the battery cells towards the blue film surface. An automatic air blowing mechanism, integrated on the profile bracket, includes multiple perforated blowing tubes arranged along the length of the battery string. The air outlet of each blowing tube faces the surface of the battery cell that is adsorbed by the string-retrieving suction cup and pressed by the recurving pressure block. It is used to simultaneously blow compressed air onto the surface of the battery cell to achieve forced convection cooling while the flipping and recurving action is performed. The intelligent temperature control system detects the temperature of the battery string and the temperature and speed of compressed air blowing, and feeds this information back to the compressed air speed control valve to automatically control the air flow rate.

[0008] Furthermore, the intelligent temperature control system includes: A temperature probe, mounted on a profile support and adjacent to the surface of the adsorbed solar cell, is used to detect the actual surface temperature T of the solar cell in real time. actual ; An air speed sensor and an air temperature sensor are located at the air outlet of the copper pipe or in the downstream airflow path, and are used to detect the actual air speed v and the actual air temperature T of the blown compressed air, respectively. env ; The compressed air automatic speed control valve has its input end connected to a compressed air source and its output end connected to the copper pipe. It is used to receive control signals and dynamically adjust the flow rate and speed of compressed air. Furthermore, it also includes a controller configured to execute the following closed-loop control logic: Receive the target temperature T set by the user set ; Based on T set With T actual The deviation of e(t)=T set T actual The desired wind speed setpoint v is generated using an outer-loop PID algorithm. ref ; Based on v ref The deviation from the wind speed v measured by the wind speed sensor is used to generate control commands for the automatic compressed air speed control valve using an inner-loop PID algorithm. And based on the T temperature feedback from the wind temperature sensor env For v ref Compensation and correction are performed to adapt the compressed air cooling process to ambient temperature fluctuations; The controller is configured to activate the automatic air blowing mechanism and the intelligent temperature control system only during the period when the flipping and recurving mechanism is performing a flipping action and the recurving block is in a downward correction state, so that the battery cell can undergo rapid thermal shrinkage and shaping simultaneously during plastic deformation, thereby suppressing warpage and springback.

[0009] Furthermore, the temperature probe is an infrared temperature probe or a contact thermocouple probe, and its installation position meets the following requirements: the distance from the surface of the adsorbed battery cell is ≤10mm, and it is located in the heat-sensitive area between the adsorption center of the stringing suction cup and the pressing area of ​​the anti-bend pressing block; the heat-sensitive area is the surface area corresponding to the maximum warp curvature of the battery cell.

[0010] Furthermore, the controller is further configured to: T collected by the temperature probe actual The signal undergoes digital filtering, which is either a moving average filter or a first-order low-pass filter, with a cutoff frequency not higher than 1Hz. When T is detected actual rate of descent dT actual When / dt exceeds a preset threshold, a feedforward compensation action is triggered to reduce the compressed air flow rate in advance.

[0011] Furthermore, the flipping and bending mechanism is also equipped with a pressure sensor for monitoring the pressure value P applied by the bending block to the battery cell; the controller is configured such that when P is in the range of 0.05 to 0.3 MPa and T actual When the temperature is in the range of 50–90℃, activate the maximum cooling intensity mode; when P > 0.3MPa or T actual When the temperature is below 50°C, the compressed air flow rate will be automatically reduced to the baseline maintenance level.

[0012] Furthermore, the profile support is provided with an air guide cavity and a flow equalization plate inside, and the air inlet ends of the multiple perforated copper pipes are all connected to the air guide cavity, and the flow equalization plate is disposed on the outlet side of the air guide cavity.

[0013] Furthermore, the air blowing pipe is a copper pipe, and there are 8 copper pipes evenly distributed on the profile support. The air outlet axis of each copper pipe is perpendicular to the center area of ​​the adsorbed battery cell, and the hole diameter is 0.8 to 1.2 mm, and the hole spacing is 35 to 55 mm.

[0014] A method for reducing the warpage of a BC battery string, applicable to the process of reducing the warpage of a BC battery string, includes the following steps: S1: The BC battery string that has been welded at high temperature is transported to the flipping and bending mechanism, where the string-retrieving suction cup adsorbs the middle of the battery string and the bending pressure block initially contacts the battery cells. S2: Activate the flipping and bending mechanism to raise it and perform a 180° flip. At the same time, the bending pressure block applies downward pressure to correct the warping, causing the battery cell to undergo controllable plastic deformation. S3: During the execution of step S2, the automatic air blowing mechanism is started simultaneously, and compressed air is blown onto the surface of the adsorbed and pressed battery cells through multiple perforated copper tubes. S4: Real-time acquisition of the actual surface temperature T of the solar cell detected by the temperature probe. actual The actual wind speed v detected by the wind speed sensor and the actual wind temperature T detected by the wind temperature sensor. env ; S5: Controller based on T set With T actual The deviation e(t) is used to obtain v through outer loop PID calculation. ref Then based on v and v ref The deviation is used to generate control commands for the automatic compressed air speed control valve through inner-loop PID calculation, and based on T env For v ref Perform dynamic compensation; S6: While the anti-bending block is kept under pressure, compressed air is maintained to blow the cells, so that the cells are rapidly cooled under stress, achieving thermo-mechanical synergistic shaping of warpage deformation. S7: After the flipping and recurving mechanism completes its action, the unloading crane removes the battery string, and the system resets to enter the next cycle; The timing of steps S3 and S5 is strictly limited to the time window from when the recurve block begins to press down until the pressure is fully released in step S2.

[0015] Furthermore, the dynamic compensation described in step S5 specifically refers to: when T env For every 1°C increase, v ref Lowered by 0.5% to 1.2%; when T env For every 1°C decrease, v ref The value was increased by 0.6% to 1.5% to maintain the relative stability of the convective heat transfer coefficient h.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention abandons the traditional pure mechanical correction mode and adopts a thermo-mechanical synergistic process of mechanical inverse plastic correction + synchronous precise air cooling and thermal shaping. While the battery cell undergoes controllable plastic deformation under external force, forced convection cooling is used to achieve rapid release of internal stress and structural shaping, which solves the problem of battery string warpage and rebound from the root and greatly improves the warpage correction effect.

[0017] 2. This device has a high degree of structural integration, and the flipping, correction, cooling and shaping processes are completed simultaneously without the need for additional processes. It has high production efficiency and can be seamlessly integrated with existing BC battery string welding production lines. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A front view of the device for reducing the warpage of BC battery strings according to the present invention; Figure 2 This is a schematic diagram of one end of the device for reducing the warping of BC battery strings according to the present invention. Figure 3 This is a schematic diagram of the arrangement of the air outlet holes on the copper tube of the present invention; Figure 4 For the present invention Figure 3 A magnified view of a portion of point A in the middle.

[0020] In the picture: 1- Flip-over mechanism; 12- String-picking suction cup; 13- Flip-over pressing block; 2-Automatic air blowing mechanism; 21-Air blowing pipe; 22-Air outlet; 3-Intelligent temperature control system; 31-Temperature probe; 32-Wind speed sensor; 33-Wind temperature sensor; 34-Automatic compressed air speed control valve; 4- Battery string. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0028] Example 1: Device for reducing the warpage of BC battery strings Reference Figures 1-4 The core of this invention's device consists of four parts: a flipping and bending mechanism 1, an automatic air blowing mechanism 2, an intelligent temperature control system 3, and a controller. These components work in synergy, employing a thermo-mechanical synergistic process that combines mechanical bending correction with dynamic, precise air-cooling shaping to achieve efficient, low-damage, and permanent correction of the warpage of the BC battery string 4. This completely suppresses warpage rebound and enables simultaneous mechanical correction and thermal shaping. The specific structure and assembly relationship of each component are as follows: 1. Reversing mechanism 1 The flipping and bending mechanism 1 is the main mechanical correction component of the device. Its core function is to flip the BC battery string 4 180° after high-temperature welding and achieve controllable plastic deformation of the battery cells by applying precise downward pressure. Its core load-bearing structure is a profile support, which can be processed and formed from high-strength aluminum alloy profiles. It has the characteristics of being lightweight, rigid, and not easily deformed, which can ensure the structural stability of long-term high-frequency operation.

[0029] The profile support is symmetrically equipped with string-retrieving suction cups 12 on both sides. The string-retrieving suction cups 12 adopt a multi-point vacuum adsorption structure, specifically adsorbing the middle area of ​​the battery string 4. This area is the force balance center of the battery string 4, which can avoid deformation caused by uneven local force on the battery cells during adsorption, and at the same time provide stable support for the subsequent downward pressure of the anti-bending pressure block 13. The profile support is equipped with anti-bending pressure block 13 corresponding to the core warping area of ​​the battery cell. The anti-bending pressure block 13 is made of flexible anti-slip material to avoid damaging the coating on the surface of the battery cell.

[0030] A rotary cylinder is mounted at the end of the profile bracket. This cylinder serves as the power source, precisely driving the profile bracket to rotate smoothly from 0° to 180°, with the rotation angle error controlled within ±0.5°, ensuring a smooth and vibration-free flipping motion. Simultaneously, the flipping and recurving mechanism 1 integrates a pressure sensor, which is installed in conjunction with the recurving pressure block 13. This sensor monitors the real-time pressure value P applied by the recurving pressure block 13 to the battery cells, providing pressure parameters for subsequent intelligent temperature control and cooling intensity adjustment.

[0031] 2. Automatic air blowing mechanism The automatic air blowing mechanism 2 is integrated and fixed on the profile support, and is assembled with the flipping and recurving mechanism 1. It can flip and move synchronously with the profile support, ensuring that the cooling operation and the correction action are completely synchronized. The air blowing body of the automatic air blowing mechanism 2 consists of 8 perforated air blowing pipes 21. The air blowing pipes 21 can be made of copper pipes. The 8 copper pipes are evenly distributed along the length of the battery string 4, which is compatible with the size and specifications of the conventional BC battery string 4, and can achieve full coverage cooling of the battery cells.

[0032] The vent 22 of each copper tube is perpendicularly aligned with the center area of ​​the solar cell that is adsorbed by the string-taking suction cup 12 and pressed by the anti-bending pressure block 13, precisely targeting the heat-sensitive area with the greatest warpage curvature of the solar cell. The diameter of the vent 22 of the copper tube is set to 0.8-1.2 mm, preferably 1 mm, and the spacing between the vents is controlled to be 35-55 mm to ensure uniform airflow density and no cooling blind spots. In this embodiment, the vent spacing is distributed as follows: Figure 3 and Figure 4 As shown, the hole spacing is set alternately at two intervals: 38.5mm and 53.5mm. In practice, the hole spacing can be flexibly set according to the position of the battery cells on the battery string 4.

[0033] The profile support has a pre-reserved hollow structure to form an air guide cavity. A flow equalization plate is fixedly installed on the outlet side of the air guide cavity, and the air inlet ends of the eight perforated copper pipes are all uniformly connected to the interior of the air guide cavity. The flow equalization plate can adopt a multi-hole flow equalization structure, which can divide and stabilize the compressed air entering each copper pipe, so that the outlet air velocity deviation of all copper pipes is ≤±8%, which completely solves the problem of uneven airflow in a single copper pipe and large local temperature differences in the battery cells, ensuring the overall cooling consistency of the battery string 4.

[0034] Meanwhile, the compressed air supplied with the device must be pre-cooled and dehumidified by the air conditioning unit in advance. The temperature of the air after pre-cooling must be strictly controlled within the range of 10 to 25°C, and the relative humidity of the compressed air must be ≤40% to avoid condensation and oxidation on the surface of the battery cells caused by humid and low-temperature airflow, thus ensuring the appearance and performance quality of the battery cells.

[0035] 3. Intelligent temperature control system The intelligent temperature control system 3 is the core control unit of the device, responsible for real-time detection and dynamic control of all parameters. It includes four core components: temperature probe 31, wind speed sensor 32, wind temperature sensor 33, and compressed air automatic speed control valve 34.

[0036] Temperature probe 31 is selected from infrared temperature probes or contact thermocouple probes, with high-precision infrared temperature probes preferred. Non-contact temperature measurement avoids probe interference with the operation of the solar cells. Temperature probe 31 is fixed on the profile bracket, close to the surface of the solar cell being adsorbed, with the installation distance strictly controlled to ≤10mm. It is precisely positioned in the heat-sensitive area between the adsorption center of the string-taking suction cup 12 and the pressing area of ​​the anti-bend pressing block 13. This area is where the solar cell warpage curvature is greatest and the temperature change is most sensitive, allowing for accurate acquisition of the actual surface temperature T of the solar cell. actual .

[0037] Both the wind speed sensor 32 and the air temperature sensor 33 are installed in the airflow path downstream of the copper pipe outlet 22, which can accurately detect the actual wind speed v and the actual air temperature T of the compressed air being blown out in real time. env The detection data is transmitted to the controller in real time. The input end of the compressed air automatic speed control valve 34 is connected to the industrial compressed air source, and the output end is connected to the air guide cavity of the profile support. It can receive the control signal from the controller and dynamically and steplessly adjust the compressed air supply flow rate and blowing speed.

[0038] 4. Controller and closed-loop control logic The controller is the core computing and control unit of the device, and it has built-in dual PID closed-loop control program, signal filtering program, feedforward compensation program, and operating condition linkage control program. The specific configuration logic is as follows: (1) Dual PID closed-loop temperature control logic: The controller first receives the manually preset target shaping temperature T of the battery cell. set Calculate the deviation between the target temperature and the actual temperature e(t) = T set T actual The desired wind speed setpoint v is generated through outer-loop PID algorithm calculation. ref Then compare the expected wind speed v in real time. ref The actual wind speed v measured by the wind speed sensor 32 is used to generate precise control commands through an inner-loop PID algorithm, driving the compressed air automatic speed control valve 34 to adjust the operating conditions and achieve precise temperature-wind speed dual closed-loop control. Simultaneously, the controller can adjust the ambient wind temperature T fed back by the wind temperature sensor 33. env For v ref Dynamic compensation is implemented to adapt to ambient temperature fluctuations and ensure stable cooling and heat exchange performance. The specific compensation rule is: T env For every 1°C increase, v ref Reduce by 0.5% to 1.2%, preferably 1.0%; T env For every 1°C decrease, v ref Increase by 0.6% to 1.5%, preferably 1.2%, to maintain the convective heat transfer coefficient h relatively constant.

[0039] (2) Signal filtering and feedforward compensation logic: The controller analyzes the T signal collected by the temperature probe 31. actual The raw signal undergoes digital filtering, employing either moving average filtering or first-order low-pass filtering, with a filter cutoff frequency not exceeding 1Hz. This effectively filters out temperature noise and transient interference signals from the production environment, ensuring stable and reliable temperature measurement data. Simultaneously, the controller calculates the cell cooling rate dT in real time. actual When the cooling rate exceeds the system's preset threshold, the feedforward compensation action is automatically triggered to slightly reduce the compressed air flow in advance, so as to avoid the battery cells from undergoing temperature stress deformation due to excessively rapid cooling.

[0040] (3) Working condition linkage control logic: The controller sets exclusive linkage trigger conditions. Only when the flipping and bending mechanism 1 performs the flipping action and the bending block 13 is in the effective working range of downward correction, the automatic blowing mechanism 2 and the intelligent temperature control system 3 are activated to work together. When the bending block 13 is lifted and the pressure is released, the strong cooling stops synchronously to ensure that the battery cell completes rapid heat shrinkage and shaping only during the plastic deformation process, and maximizes the suppression of warpage and rebound.

[0041] (4) Zoned cooling intensity control logic: The controller automatically switches the cooling mode based on the pressure signal from the pressure sensor and the temperature signal from the temperature probe 31: when the pressure P applied by the recurved pressure block 13 is in the range of 0.05 to 0.3 MPa and the actual temperature T of the battery cell is within the range of 0.05 to 0.3 MPa. actual When the temperature is between 50 and 90°C, the system determines this to be the optimal range for plastic shaping and automatically activates the maximum cooling intensity mode to quickly complete the heat shaping. However, when P > 0.3 MPa (excessive pressure can damage the battery cells) or T... actualWhen the temperature is below 50℃ (the cell temperature is too low and plastic deformation is complete), the compressed air flow rate is automatically reduced to the basic maintenance level, saving energy and protecting the cells.

[0042] Example 2: Method for reducing the warpage of BC battery string 4 This embodiment, based on the device of Embodiment 1, achieves thermal-mechanical coordinated shaping and correction of warpage in BC battery string 4. The complete operation steps are as follows: S1: Loading, adsorption and positioning: The BC battery string 4, which has been welded at high temperature, is accurately transported to the working area of ​​the flipping and bending mechanism 1 through the conveyor line. After the equipment is initialized and reset, the string suction cup 12 starts vacuum adsorption and stably adsorbs the middle area of ​​the battery string 4 to complete the positioning and fixing of the battery string 4. Then the bending pressure block 13 moves down to initially contact the surface of the battery cell to complete the pre-pressure positioning.

[0043] S2: Reversal Plastic Deformation: Start the reversal mechanism 1, the rotating cylinder drives the profile support and battery string 4 to rise smoothly and perform a 180° reversal action. During the entire reversal process, the reversal pressure block 13 continuously applies constant pressure downwards to forcibly correct the warping deformation of the battery cell that was originally facing the blue film surface, so that the battery cell produces controllable reverse plastic deformation and eliminates the original warping structure.

[0044] S3: Synchronous activation of forced air cooling: At the moment the recurved pressing block 13 begins to press down in step S2, the automatic air blowing mechanism 2 and the intelligent temperature control system 3 are activated simultaneously. The pre-cooled and dehumidified compressed air is stabilized and evenly distributed through the air guide cavity and the flow equalization plate, and then blown vertically onto the surface of the battery cell pressing area through 8 perforated copper pipes to force convection cooling of the battery cell in the plastic deformation state.

[0045] S4: Real-time acquisition of multiple parameters: During operation, temperature probe 31 acquires the actual surface temperature T of the battery cell in real time. actual The wind speed sensor 32 and the wind temperature sensor 33 collect the actual wind speed v and actual wind temperature T of the blowing air in real time. env The pressure sensor collects the pressing pressure P in real time, and all detection data is uploaded to the controller in real time.

[0046] S5: Closed-loop dynamic temperature control: The controller receives the user-preset target temperature T. set The desired wind speed v is generated based on the temperature deviation through outer-loop PID calculation. ref Combined with ambient wind temperature T env The wind speed compensation correction is completed; then, the speed control valve control command is generated based on the wind speed deviation through inner loop PID calculation, and the compressed air flow rate and velocity are dynamically adjusted to meet the real-time cooling requirements of the battery cells.

[0047] S6: Thermal-Mechanical Synergistic Shaping and Curing: Throughout the entire time window during which the inverted bending block 13 continuously presses down and maintains pressure, a constant forced air cooling operation is maintained to rapidly and uniformly cool the solar cells under mechanical stress. This step strictly controls the cooling process parameters: the surface temperature of the solar cells rapidly drops from 80±5℃ to 60±3℃ within 5–15 seconds, and the maximum temperature gradient during the cooling process does not exceed 8℃ / s. This ensures uniform release of internal stress in the solar cells, completes plastic deformation and thermal shrinkage shaping, thoroughly locks in a flat structure, and suppresses subsequent warping and springback.

[0048] S7: Unloading and Reset Cycle: After the flipping and bending action is completed and the cooling and shaping are finished, the bending block 13 is lifted to release pressure, the blowing device stops the strong air supply at the same time, the unloading crane starts to take away the shaped flat battery string 4, then all mechanisms are reset, the system parameters are cleared, and the next battery string 4 processing cycle begins.

[0049] It should be noted that the timing of air cooling and temperature control in this method is strictly limited to the time window from the start of pressing down the recurved block 13 until the pressure is completely released. Air cooling and shaping are only carried out during the critical stage when the battery cell undergoes plastic deformation, which ensures the shaping effect, avoids ineffective cooling operations, and improves production efficiency.

[0050] There are several points to note regarding this plan, as follows: 1. Goal Setting Desired temperature T _set (or the expected maximum cooling rate).

[0051] 2. Detection and Feedback (the system's "Perception Layer") Main feedback: Temperature probe. Monitors the actual temperature T_ on the surface or key points of the cooled battery string. actual This is the core basis for the closed-loop mechanism.

[0052] Wind speed sensor: Directly monitors the speed of airflow blowing towards an object, used to more accurately control the "cooling rate".

[0053] Air temperature sensor: Monitors the temperature of the outflowing air (ambient temperature or temperature after air conditioning). If the air temperature is constant, the system is simpler; if the air temperature changes (such as fluctuations in ambient temperature), it is an interference that needs to be compensated for.

[0054] 3. Control Core (the system's "decision-making layer") The controller receives T_ set With T_ actual The error e(t).

[0055] The control algorithm needs to understand the dynamic relationship between the "blowing command" and the "final cooling effect".

[0056] Basic PID: Treats the entire "blowing and cooling" process as a whole space, and adjusts the compressed air outlet speed and flow rate according to the temperature error.

[0057] Inner loop (velocity loop): Using compressed air as input and measured wind speed as feedback, it quickly and stably controls the airflow speed.

[0058] Outer loop (temperature loop): Calculates the desired wind speed setpoint based on temperature error and sends it to the inner loop.

[0059] This structure can effectively resist interference such as airflow blockage, making the control of "cooling speed" more precise and faster.

[0060] 4. Execution and Cooling Process (The System's "Execution and Action Layer") Actuator: Compressed air + compressed air automatic speed control valve.

[0061] Cooling effect generator: This is a feature of the "blowing cooling" system, which uses compressed air to generate airflow.

[0062] Cooling transfer process: airflow (velocity v, temperature T) _env Impact / flow across the surface of the object being cooled (temperature T_) actual Heat is transferred through convection. This process involves thermal inertia and transfer delay.

[0063] Key parameters: convective heat transfer coefficient (related to wind speed), contact area, and heat capacity of the object.

[0064] 5. Controlled object For an object with thermal mass (heat capacity), its temperature change follows the laws of thermodynamics: heat capacity of an object dT / dt = internal heat generation power - heat dissipation from airflow.

[0065] 6. Main Interference External disturbances: Ambient temperature T _env Changes, external airflow (such as natural wind).

[0066] Internal interference: Heat generated by the object being cooled, P _heat The changes.

[0067] Changes in system characteristics: Deformation of the air duct, changes in compressed air pressure, etc., lead to a decrease in performance.

[0068] Detailed explanation of dynamic control process (considering cooling dynamics): 1. Temperature exceeds the limit: T _actual >T _set → Error e>0.

[0069] 2. Controller response: PID output increases → compressed air blowing duty cycle increases.

[0070] 3. Increased airflow: Increased compressed air flow rate and velocity → increased airflow velocity v directed toward the object.

[0071] 4. Enhanced cooling: Increased airflow velocity v → increased convective heat transfer coefficient → significantly improved cooling rate (heat dissipation).

[0072] 5. Temperature decrease: The amount of heat dissipated by an object exceeds the amount of heat generated → dT_ actual / dt<0→Temperature T _actual It has begun to descend.

[0073] 6. Feedback and Convergence: Decreasing T_ actual As the probe detects the decrease in error e, the controller correspondingly reduces the compressed air flow rate and velocity. Eventually, the system stabilizes at a dynamic equilibrium point: cooling heat dissipation = internal heat generation + environmental heat transfer. At this point, T_ actual ≈T _set .

[0074] Unique challenges and solutions in system design: 1. The installation location of the temperature probe is crucial: Temperature probes must be placed in a location that accurately reflects the temperature of the controlled target and is sensitive to airflow cooling. Placing them in a dead corner or directly under a heat source will cause control failure. Multiple probes are needed to take the average or highest value.

[0075] 2. Airflow organization design: This is the key to whether "blowing" can be effectively transformed into "cooling". Poor air duct design can lead to airflow short circuits, eddies, and uneven cooling.

[0076] Air guides, flow equalizers, etc. are needed to ensure that the airflow is directed and blows evenly over the surface that needs to be cooled.

[0077] 3. System hysteresis and inertia: Sensor hysteresis: the thermal response time of the probe itself.

[0078] Transmission lag: There is a time difference between the change in compressed air blowing and the change in airflow on the surface of an object.

[0079] Thermal inertia: When an object has a large mass and a large heat capacity, its temperature changes slowly.

[0080] Solutions: In PID algorithms, the derivative term (D) can partially predict trends and suppress overshoot caused by inertia; or more advanced model predictive control can be used.

[0081] 4. Noise and Measurement Filtering: Airflow can cause high-frequency fluctuations in probe readings. Digital filtering of the temperature signal (such as low-pass filtering or moving average) needs to be performed in the software to prevent the controller from responding drastically to noise.

[0082] 5. Adaptive control: The system can identify changes in its own characteristics online (such as reduced heat dissipation efficiency due to blockage of the compressed air outlet) and automatically adjust the PID parameters to always maintain optimal control performance.

[0083] 6. Energy saving and noise optimization: The control objectives are not only temperature, but also noise and energy consumption. The algorithm will find the balance point with the lowest compressed air flow rate while meeting the temperature requirements.

[0084] The essence of the temperature probe-based feedback-based closed-loop control system for cooling airflow lies in understanding and controlling the energy transfer chain from "airflow" to "cooling effect." It is no longer just a simple compressed air blowing control system, but an environmental control system that takes into account fluid dynamics and heat transfer characteristics.

[0085] The key point of this plan is: 1. Accurate sensing: Temperature probes and possible auxiliary sensors are properly installed.

[0086] 2. Effective execution: The compressed air flow rate and duct design can generate efficient and directional cooling airflow.

[0087] 3. Intelligent decision-making: Control algorithms (such as cascaded PID) can properly handle the inertia, hysteresis and disturbances of the system, and quickly, smoothly and accurately maintain the temperature at the set point.

[0088] Compared with existing technologies, the flipping and bending mechanism of this solution rapidly cools down the battery string during the physical force correction process. The battery string is cooled and quickly sets its shape during the bending deformation process, thus avoiding the fact that physical force correction alone cannot achieve the effect of low warping.

[0089] Summary of working principles: This invention addresses the forming mechanism of bidirectional warping after welding four BC battery strings. Breaking away from the limitations of traditional purely mechanical correction, it utilizes the core principle of high-temperature plastic deformation combined with rapid thermal shrinkage for shaping. Under the high-temperature, plastically deformable state of the battery cell, mechanical reverse pressure is applied to correct the original warping. Simultaneously, precise and uniform forced air cooling causes the battery cell substrate, insulating adhesive, and solder strips to cool and shrink rapidly, releasing internal residual stress and permanently solidifying the mechanically corrected flat structure, thus fundamentally solving the warping and springback problem. Furthermore, precise control strategies such as intelligent dual-PID closed-loop temperature control, pressure-linked temperature control, and ambient temperature compensation prevent microcracks and secondary deformation caused by uneven cooling and abnormal pressure, achieving efficient, low-damage, and highly consistent warping correction processing.

[0090] Parameter description: All structural, process, and control parameters in this solution are optimal ranges verified through multiple experiments. Specifically, these include: 8 copper tubes, hole diameter 0.8–1.2 mm, hole spacing 35–55 mm; cooling air temperature 10–25℃, humidity ≤40%; working pressure range 0.05–0.3 MPa; cooling time 5–15 s, cooling range 80±5℃ to 60±3℃, maximum temperature gradient ≤8℃ / s; wind speed compensation coefficient 0.5%–1.5%; airflow uniformity deviation ≤±8%; filter cutoff frequency ≤1Hz. All parameters work together to ensure the optimal implementation effect of the device and method.

[0091] The beneficial effects of the technical solution of the present invention are: 1. This invention abandons the traditional pure mechanical correction mode and adopts a thermo-mechanical synergistic process of mechanical inverse plastic correction + synchronous precise air cooling and thermal shaping. While the battery cell undergoes controllable plastic deformation under external force, forced convection cooling is used to achieve rapid release of internal stress and structural shaping, which solves the problem of battery string 4 warpage and springback from the root and greatly improves the warpage correction effect.

[0092] 2. Through a smart temperature control strategy of dual PID closed-loop control and ambient temperature compensation, the cooling wind speed and flow rate are precisely adjusted to match the cooling rate of the battery cells, avoiding new stress deformation caused by excessive instantaneous temperature difference. At the same time, it avoids the problems of hidden cracks and edge breakage caused by pure mechanical forced pressure, significantly improving the yield of battery string 4.

[0093] 3. By limiting core process parameters such as cooling time, temperature gradient, pressure range, and wind speed compensation, and combining them with a flow equalization and air guiding structure, the overall cooling of the battery string 4 is ensured to be uniform, the stress is stable, the calibration consistency is high, and it is suitable for large-scale industrial production.

[0094] 4. The device has a high degree of structural integration, and the flipping, correction, cooling and shaping processes are completed simultaneously without the need for additional processes. It has high production efficiency and can be seamlessly integrated with existing BC battery string 4 welding production lines.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for reducing the warpage of BC battery strings, characterized in that, include: The flipping and bending mechanism is used to flip and physically correct the BC battery strings that have been welded at high temperature. The flipping and bending mechanism includes a profile support, string-picking suction cups and bending pressure blocks on both sides of the profile support, and a rotary cylinder that drives the profile support to rotate. The string-picking suction cups are used to pick up the middle area of ​​the battery string, and the bending pressure blocks are used to apply downward pressure during the flipping process to correct the warping of the battery cells towards the blue film surface. An automatic air blowing mechanism, integrated on the profile bracket, includes multiple perforated blowing tubes arranged along the length of the battery string. The air outlet of each blowing tube faces the surface of the battery cell that is adsorbed by the string-retrieving suction cup and pressed by the recurving pressure block. It is used to simultaneously blow compressed air onto the surface of the battery cell to achieve forced convection cooling while the flipping and recurving action is performed. The intelligent temperature control system is used to detect the temperature of the battery string and the speed and temperature of compressed air blowing, and feeds this information back to the compressed air speed control valve to automatically control the air flow rate.

2. The apparatus according to claim 1, characterized in that, The intelligent temperature control system includes: A temperature probe, mounted on a profile support and adjacent to the surface of the adsorbed solar cell, is used to detect the actual surface temperature T of the solar cell in real time. actual ; An air velocity sensor and an air temperature sensor are located at the air outlet of the air blowing pipe or in the downstream airflow path, and are used to detect the actual air velocity v and the actual air temperature T of the blown compressed air, respectively. env ; The compressed air automatic speed control valve has its input end connected to a compressed air source and its output end connected to the air blowing pipe. It is used to receive control signals and dynamically adjust the flow rate and velocity of compressed air.

3. The apparatus according to claim 2, characterized in that, It also includes a controller configured to execute the following closed-loop control logic: Receive the target temperature T set by the user set ; Based on T set With T actual The deviation of e(t)=T set T actual The desired wind speed setpoint v is generated using an outer-loop PID algorithm. ref ; Based on v ref The deviation from the wind speed v measured by the wind speed sensor is used to generate control commands for the automatic compressed air speed control valve using an inner-loop PID algorithm. And based on the T temperature feedback from the wind temperature sensor env For v ref Compensation and correction are performed to adapt the compressed air cooling process to ambient temperature fluctuations; The controller is configured to activate the automatic air blowing mechanism and the intelligent temperature control system only during the period when the flipping and recurving mechanism is performing a flipping action and the recurving block is in a downward correction state, so that the battery cell can undergo rapid thermal shrinkage and shaping simultaneously during plastic deformation, thereby suppressing warpage and springback.

4. The apparatus according to claim 3, characterized in that, The temperature probe is an infrared temperature probe or a contact thermocouple probe, and its installation position meets the following requirements: the distance from the surface of the adsorbed battery cell is ≤10mm, and it is located in the heat-sensitive area between the adsorption center of the string suction cup and the pressing area of ​​the anti-bend pressing block; the heat-sensitive area is the surface area corresponding to the maximum warp curvature of the battery cell.

5. The apparatus according to claim 3, characterized in that, The controller is also configured to: T collected by the temperature probe actual The signal undergoes digital filtering, which is either a moving average filter or a first-order low-pass filter, with a cutoff frequency not higher than 1Hz. When T is detected actual rate of descent dT actual When / dt exceeds a preset threshold, a feedforward compensation action is triggered to reduce the compressed air flow rate in advance.

6. The apparatus according to claim 3, characterized in that, The flipping and bending mechanism is also equipped with a pressure sensor to monitor the pressure value P applied by the bending block to the battery cell; the controller is configured to: when P is in the range of 0.05 to 0.3 MPa and T actual When the temperature is in the range of 50–90℃, activate the maximum cooling intensity mode; when P > 0.3MPa or T actual When the temperature is below 50°C, the compressed air flow rate will be automatically reduced to the baseline maintenance level.

7. The apparatus according to claim 1, characterized in that, The profile support has an air guide cavity and a flow equalization plate inside. The air inlet ends of multiple air blowing pipes are all connected to the air guide cavity, and the flow equalization plate is set on the outlet side of the air guide cavity.

8. The apparatus according to claim 1, characterized in that, The air blowing pipe is a copper pipe, and there are 8 copper pipes evenly distributed on the profile support. The air outlet axis of each copper pipe is perpendicular to the center area of ​​the adsorbed battery cell, and the hole diameter is 0.8 to 1.2 mm, and the hole spacing is 35 to 55 mm.

9. A method for reducing the warpage of a BC battery string, applied to the method for reducing the warpage of a BC battery string as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: The BC battery string that has been welded at high temperature is transported to the flipping and bending mechanism, where the string-retrieving suction cup adsorbs the middle of the battery string and the bending pressure block initially contacts the battery cells. S2: Activate the flipping and bending mechanism to raise it and perform a 180° flip. At the same time, the bending pressure block applies downward pressure to correct the warping, causing the battery cell to undergo controllable plastic deformation. S3: During the execution of step S2, the automatic air blowing mechanism is started simultaneously, and compressed air is blown onto the surface of the adsorbed and pressed battery cells through multiple perforated copper tubes. S4: Real-time acquisition of the actual surface temperature T of the solar cell detected by the temperature probe. actual The actual wind speed v detected by the wind speed sensor and the actual wind temperature T detected by the wind temperature sensor. env ; S5: Controller based on T set With T actual The deviation e(t) is used to obtain v through outer loop PID calculation. ref Then based on v and v ref The deviation is used to generate control commands for the automatic compressed air speed control valve through inner-loop PID calculation, and based on T env For v ref Perform dynamic compensation; S6: While the anti-bending block is kept under pressure, compressed air is maintained to blow the cells, so that the cells are rapidly cooled under stress, achieving thermo-mechanical synergistic shaping of warpage deformation. S7: After the flipping and recurving mechanism completes its action, the unloading crane removes the battery string, and the system resets to enter the next cycle; The timing of steps S3 and S5 is strictly limited to the time window from when the recurve block begins to press down until the pressure is fully released in step S2.

10. The method according to claim 9, characterized in that, The dynamic compensation mentioned in step S5 specifically refers to: when T env For every 1°C increase, v ref Lowered by 0.5% to 1.2%; when T env For every 1°C decrease, v ref The value was increased by 0.6% to 1.5% to maintain the relative stability of the convective heat transfer coefficient h.

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