A flexible gluing method for a new energy vehicle battery box

Abstract

The application provides a new energy automobile battery box multi-vehicle type flexible gluing and assembling method, and relates to the technical field of power battery shell manufacturing. The new energy automobile battery box multi-vehicle type flexible gluing and assembling method identifies the workpiece vehicle type by scanning the code, drives the servo positioning unit to automatically switch to the corresponding reference coordinate, realizes quick model change, adopts a ladder type preheating activation process, synchronously completes the composite coating of structural adhesive and pouring adhesive, suppresses the thermal warping deformation of large aluminum parts through integrated curing by heating and pressing, decouples the 90-minute cooling process from the main line production rhythm by combining the advanced first-in-first-out three-dimensional buffer library, realizes early defect identification and process closed-loop control through the matching multi-stage air tightness detection shunting and CCD full-size adaptive compensation. The application can be compatible with the production of battery boxes of various sizes, the positioning accuracy is ±0.05mm, the whole line rhythm is stable, the comprehensive efficiency of the equipment is greater than or equal to 80%, the gluing quality and production flexibility are effectively improved, and the rework cost is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of power battery casing manufacturing, and more specifically, to a flexible coating method for multi-model battery boxes for new energy vehicles. Background Technology

[0002] With the rapid development of electric vehicles, the battery box, as the core structural component carrying the battery cells, is becoming increasingly complex in its manufacturing process. Currently, mainstream battery boxes adopt a composite structure of aluminum profile frame + base plate + water-cooling plate, involving the application of various adhesives during manufacturing, including structural adhesives, thermally conductive potting compounds, and foam sealants. Existing technologies have the following prominent problems: 1. Difficulty in integrating multiple materials and processes: Different adhesives have significantly different application windows and curing conditions regarding temperature, time, and pressure. For example, structural adhesives require room temperature or low temperature curing, potting compounds require preheating activation, and foaming adhesives require high temperature and high pressure curing. Traditional production lines are usually designed for a single adhesive process, making integrated production difficult. This results in fragmented processes, frequent handling, and poor quality consistency.

[0003] 2. Challenges in Flexible Co-production of Large Battery Boxes: The EB5X5 model is approximately 2234mm long, and the EB5Y5 model is approximately 2064mm long. The battery box lengths vary significantly between these models, although their widths are similar. Existing production lines mostly use dedicated fixtures, requiring manual replacement of the entire fixture set during model changes, which takes several hours and cannot meet the needs of mixed-model production, resulting in low equipment utilization.

[0004] 3. Thermal deformation and uneven temperature field during the heating and curing process: Large, thin-walled aluminum parts such as base plates or frames are prone to thermal warping deformation during heating and curing, affecting the final assembly accuracy. Traditional oven heating methods are energy-intensive, slow to heat up, and have poor temperature uniformity, resulting in incomplete or over-curing of the adhesive and a decrease in bond strength.

[0005] 4. Conflict between long cooling or curing processes and production line cycle time: Foaming adhesive requires approximately 90 minutes of cooling and curing time after application, and potting compound also requires a curing window of several tens of minutes. If online waiting is adopted, the overall line cycle time will be significantly lengthened, with the production cycle for a single unit exceeding 2 hours, making mass production impossible, and the overall equipment effectiveness (OEE) typically below 50%.

[0006] 5. Delayed defect detection and high rework costs: Existing production lines often only conduct airtightness and dimensional inspections at the final workstation. Once defective products are found, all the high-value-added processes such as multiple gluing or pressing steps that have been completed become wasteful, and rework is difficult and costly. Summary of the Invention

[0007] This invention enables flexible automated glue application and assembly production lines that are compatible with two or more battery boxes of different lengths and sizes, allowing for rapid model changeover.

[0008] To address the above problems, this invention provides a flexible adhesive coating method for multi-model new energy vehicle battery boxes, comprising the following steps: S1: Identify the current workpiece model and automatically switch the flexible positioning system of each station to the corresponding positioning coordinates according to the model; S2: Preheat the water-cooled plate of the battery box to 50-60℃ and apply structural adhesive to the front of the frame; S3: Combine the preheated water-cooled plate with the frame, and apply the potting compound within 45 seconds while maintaining an environment of 53-57℃. Then, perform heat preservation and curing to achieve an initial curing strength of 3MPa. S4: Apply structural adhesive to the bottom plate of the battery box and spray foam adhesive on the back of the water-cooling plate. S5: After the base plate and water-cooled plate assembly are molded together, they are heated and pressurized for integrated curing; S6: Store the cured workpiece in the asynchronous buffer cooling system and remove it after staying for no less than 90 minutes; S7: Perform an airtightness test on the foam area of ​​the cooled workpiece, and automatically divert unqualified parts to the rework area; S8: Assemble the longitudinal beams, transverse beams and sleeves, and perform airtightness testing on the sleeves; unqualified parts are automatically diverted. S9: Perform full-size CCD inspection on qualified workpieces and dynamically compensate for previous adhesive application or positioning parameters based on the inspection data.

[0009] Optionally, in step S1, the switching method of the flexible positioning system is as follows: the control system stores the positioning coordinates of at least two vehicle models, the servo motor drives the positioning pin to move along the guide rail to the target position, the displacement sensor feeds back the actual position, and the system locks after the deviation is ≤ ±0.05mm, and the model switching time is ≤3 seconds.

[0010] Optionally, in step S2, the water-cooled plate preheating is performed using a heating fixture, with temperature uniformity ≤ ±2℃, which is ensured by zoned PID control and thermocouple monitoring.

[0011] Optionally, in step S3, the coating of the potting compound is carried out by two coating robots working together; the heat preservation and curing is carried out by using the heating plate of the subsequent pressing station to keep it at 60°C for 15 minutes.

[0012] Optionally, in step S4, the foaming adhesive is a two-component polyurethane foaming adhesive with a two-component mixing ratio of 100:120, the raw material temperature is controlled at 28±3℃, the spray gun pressure is 0.5-0.8MPa, and the coating thickness is controlled at 3mm.

[0013] Optionally, in step S5, the integrated heating and pressurization curing is performed simultaneously in the same device: the lower heating plate heats the workpiece to 80°C, the upper pressure plate descends at a speed of 0.5 mm / s and applies 10 tons of pressure, and the pressure holding time is 10 minutes; the temperature curve and pressure curve are recorded in real time during the curing process.

[0014] Optionally, in step S6, the asynchronous buffer cooling system adopts a first-in-first-out three-dimensional buffer library with a capacity of at least 6 workpieces. Each workpiece is recorded with a timestamp when it enters the library and can only be taken out after a stay time of ≥90 minutes. The buffer library adopts a steel structure with a floor height of 200mm, and each compartment is equipped with an independent pull-out tray.

[0015] Optionally, in step S7, the airtightness test of the foam area adopts the differential pressure method: the test pressure is 10kPa±0.5kPa, the pressure holding time is 60 seconds, and the leakage rate is ≤1.5cc / min to be qualified; unqualified parts are sent to the offline rework area.

[0016] Optionally, in step S8, the sleeve air tightness test adopts the differential pressure method. The test pressure is set according to the sleeve specifications, and the leakage rate is ≤0.5cc / min as qualified; unqualified parts are sent to the offline rework area.

[0017] Optionally, in step S9, the full-size CCD inspection includes: using 144 high-resolution CCD cameras with a camera pixel count ≥ 5 million, lens distortion ≤ 0.1%, and inspection time ≤ 130 seconds / piece to inspect the position accuracy of key mounting holes, the outer contour dimensions, and the adhesive application trajectory.

[0018] The beneficial effects of the flexible adhesive coating method for multi-model battery boxes of new energy vehicles according to the present invention are: 1. Extremely flexible changeover: The servo-driven movable positioning unit enables changeover in seconds, is compatible with multiple vehicle models, eliminates the need to store a large number of special fixtures, reduces tooling costs by about 60%, and achieves a positioning repeatability of ±0.05mm.

[0019] 2. Perfect compatibility with multiple adhesive types: Differentiated processes are designed for the characteristics of different adhesives. Stepped preheating reduces the initial curing time of potting compound from 4 hours to 15 minutes. Integrated heating and pressing shortens the curing process of foamed adhesive to 10 minutes, enabling continuous operation of multiple adhesive types.

[0020] 3. Significantly improved product quality: Continuous and uniform pressure is applied during the curing process, which effectively inhibits thermal warping deformation of aluminum parts, ensuring product flatness ≤0.5mm / m and increasing the bonding strength of foam adhesive by more than 30%; multi-level airtightness testing enables early detection and precise location of defects, and the first-pass yield rate of the entire line is ≥90%.

[0021] 4. Strong process stability: CCD full-size inspection and process adaptive compensation form a closed loop, reducing dimensional drift caused by fixture wear and temperature changes; full-process data traceability meets the IATF 16949 quality requirements of the automotive industry. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of a flexible adhesive coating method for multi-model battery boxes of new energy vehicles according to an embodiment of the present invention. Detailed Implementation

[0023] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0024] The term "comprising" and its variations as used herein are open-ended inclusion, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the description below.

[0025] like Figure 1 As shown in the figure, an embodiment of the present invention provides a flexible adhesive coating method for multi-model new energy vehicle battery boxes, which includes the following steps: S1: Identify the current workpiece model and automatically switch the flexible positioning system of each station to the corresponding positioning coordinates based on the workpiece model.

[0026] S2: Preheat the water-cooled plate of the battery box to 50-60℃, apply structural adhesive to the front of the frame along the preset trajectory, and after applying the adhesive, use a laser sensor to detect the width and continuity of the adhesive line, and issue an alarm for any defective parts.

[0027] S3: Assemble the preheated water-cooled plate with the frame, and apply the potting compound within 45 seconds while maintaining an environment of 53-57℃; heat-insulate and cure the components coated with potting compound until they reach an initial curing strength of 3MPa; check the condition of the grout and install a temporary protective cover; divert unqualified parts to the offline rework area.

[0028] S4: Apply structural adhesive to the bottom plate of the battery box and spray foam adhesive on the back of the water-cooling plate.

[0029] S5: After the base plate and water-cooled plate assembly are molded together, they are heated and pressurized for integrated curing. The curing temperature is 70-100℃, the pressure is 5-15 tons, and the pressure is maintained for 8-15 minutes.

[0030] S6: Store the cured workpiece in an asynchronous buffer cooling system for cooling, and remove it after a minimum of 90 minutes.

[0031] S7: Perform an airtightness test on the foamed area of ​​the cooled workpiece, and automatically divert unqualified parts to the rework area.

[0032] S8: Assemble the longitudinal beams, transverse beams, and sleeves, and perform an airtightness test on the sleeves. Defective parts are automatically diverted to the rework area.

[0033] S9: Perform full-size CCD inspection on qualified workpieces and dynamically compensate for previous adhesive application or positioning parameters based on the inspection data.

[0034] In this embodiment, by identifying vehicle models and automatically switching to the flexible positioning system, the problems of time-consuming model changeovers and low equipment utilization in multi-model mixed-line production are effectively solved. The integrated application of multiple adhesives is achieved through preheating the water-cooled plate, applying potting compound under specific conditions and heat preservation curing, and applying structural adhesive to the base plate and spraying foaming adhesive on the back of the water-cooled plate. Integrated heating and pressurization curing controls the thermal deformation of large, thin-walled parts. An asynchronous buffer cooling system decouples the long-term cooling and curing process from the production line cycle time, improving production efficiency. Online airtightness testing and full-size CCD inspection and data compensation prevent defect accumulation and reduce rework costs.

[0035] Specifically, in step S1, the DM code of the workpiece is read by the barcode scanner at the loading station, the control system identifies the current workpiece model, and records the production serial number. The control system sends the target position command to the servo drive positioning unit at each station. The servo motor drives the left and right positioning pins to move along the guide rail, the displacement sensor feeds back the actual position, and locks the position after the deviation is ≤±0.05mm. The changeover time is ≤3 seconds.

[0036] The control system stores the positioning coordinates of at least two vehicle models. This system is the core of flexible multi-model production, pre-storing the precise position information of the battery boxes for different models at the gluing station. These positioning coordinates can be three-dimensional spatial coordinates, used to guide the positioning mechanism to accurately place the workpieces. For example, the control system can be based on a PLC (Programmable Logic Controller), using an HMI (Human Machine Interface) for vehicle model selection and coordinate parameter loading; alternatively, it can be based on an industrial PC, combined with a database management system to store and retrieve CAD data or preset coordinate points for different vehicle models.

[0037] A servo motor drives the positioning pin to move along the guide rail to the target position. As a high-precision motion control actuator, the servo motor is responsible for driving the positioning pin to perform precise position adjustments. The positioning pin is the component that directly contacts the battery box workpiece; its movement along the guide rail ensures the stability and repeatability of the positioning process. For example, a linear servo motor can be used to directly drive the positioning pin to move on the linear guide rail, achieving high dynamic response and positioning accuracy; alternatively, a rotary servo motor can be used to drive the positioning pin to move on the linear guide rail via a gear and rack mechanism or a ball screw mechanism.

[0038] The displacement sensor provides feedback on the actual position. It monitors the current position of the positioning pin in real time and feeds this information back to the control system, forming a closed-loop control. This is a crucial step in ensuring positioning accuracy. For example, a high-precision optical encoder can be used as a displacement sensor to directly measure the linear displacement of the positioning pin, providing micron-level feedback accuracy; alternatively, a magnetostrictive displacement sensor or encoder can be used in conjunction with a ball screw to indirectly measure the position of the positioning pin.

[0039] The system locks after a deviation of ≤±0.05mm; this describes the positioning accuracy requirement and locking mechanism. When the deviation between the actual position reported by the displacement sensor and the target position reaches or is less than ±0.05mm, the control system triggers the locking mechanism to ensure the positioning pin remains stable during the adhesive application process and prevents displacement. For example, a pneumatic or hydraulic clamping mechanism can be used, which, after reaching the required accuracy, drives the clamp to firmly lock the positioning pin onto the guide rail via a cylinder or hydraulic cylinder; alternatively, an electromagnetic brake or mechanical self-locking mechanism can be used, which automatically or via control commands locks the pin after the servo motor stops moving and reaches the target position.

[0040] A changeover time of ≤3 seconds is a quantitative indicator of system switching efficiency, representing the time required to switch from one vehicle model to another and complete the entire positioning and locking process. For example, the movement and feedback time of the positioning pin can be shortened by optimizing the acceleration and deceleration curves of the servo motor, improving the response speed of the control system, and using high-speed displacement sensors. Alternatively, a pre-loading mechanism can be used to pre-calculate and prepare the positioning parameters for the next vehicle model while the current model is being produced, reducing the waiting time during actual switching.

[0041] In this embodiment, rapid and precise switching between multiple vehicle models is achieved on the battery box production line. The control system pre-stores the positioning coordinates of various vehicle models, enabling the equipment to automatically retrieve the corresponding parameters based on the identified vehicle model information, avoiding efficiency losses caused by manual intervention. Using a servo motor to drive the positioning pin along the guide rail allows for flexible adaptation to the positioning requirements of battery boxes of different sizes, embodying the core logic of flexible manufacturing. Displacement sensors provide real-time feedback on the actual position and compare it with the target position. Closed-loop control ensures that the positioning deviation is kept within a minimal range. This high-precision positioning guarantees the trajectory stability of the subsequent adhesive coating process. A locking mechanism ensures the stability of the positioning pin during operation. Combined with a fast-response drive and feedback system, the changeover time is significantly shortened to less than 3 seconds, effectively solving the problems of long changeover times and difficulty in guaranteeing accuracy in traditional production lines. This provides a reliable hardware and control foundation for multi-vehicle mixed-line production, thereby significantly improving the flexibility of the production line and the overall efficiency of the equipment.

[0042] Specifically, in step S2, the robot picks up the water-cooled plate and places it on the heating fixture, heating it to 50-60℃. Temperature uniformity is ensured through zoned PID control (i.e., proportional-integral-derivative control) and thermocouple monitoring. The robot places the frame on the heating fixture and clamps it, then applies 9050L structural adhesive along a preset trajectory, with an adhesive width of 6mm and an adhesive height of 2mm at a coating speed of 50mm / s. This step also uses a flexible positioning system, similar to step S1, which can automatically adjust the position of the positioning pins according to the vehicle model. After adhesive application, a laser sensor detects the adhesive line width and continuity, and an alarm is triggered for defective products.

[0043] Maintaining the frame at 40-50℃ in this step helps the structural adhesive spread better and improves bond strength.

[0044] A heating fixture is an auxiliary device specifically designed for the precise heating of workpieces. Its main function is to provide a stable and efficient heat source and achieve effective heat transfer through direct or indirect contact with the workpiece. Heating fixtures can take various forms; for example, they can be passive heating blocks, where heat is conducted to the fixture via an external heat source such as a heating plate or hot air, and then conducted from the fixture to a water-cooled plate; alternatively, they can be active heating fixtures, which integrate internal electric heating elements to directly generate and precisely control heat. The fixture is typically made of metals or composite materials with good thermal conductivity and high-temperature resistance to ensure efficient and uniform heat transfer.

[0045] Meanwhile, this invention employs zoned PID control. Zoned PID control is an advanced temperature control strategy, the core of which lies in dividing the area to be heated into multiple independent control zones and equipping each zone with an independent PID controller. Each PID controller independently calculates and adjusts the heating power output based on the real-time temperature feedback of its corresponding zone to achieve the set target temperature. This control method can effectively address the problem of inconsistent thermal response caused by differences in geometry, material thickness, or heat conduction paths in different parts of the workpiece, thereby achieving refined management and uniform control of the overall temperature field. For example, multiple independent heating units can be driven by multi-channel solid-state relays (SSRs), with each unit precisely regulated by a PID controller; or, multiple PID algorithm modules can be integrated through a programmable logic controller to centrally coordinate and distribute the heating power of different zones.

[0046] Furthermore, this invention also utilizes thermocouple monitoring. Thermocouple monitoring is a commonly used temperature measurement technique. Its principle is based on the Seebeck effect, which generates a thermoelectric electromotive force in the circuit when two different conductors or semiconductors are connected at their ends and the temperatures of the two junctions are different. During the preheating process of the water-cooled plate, thermocouples are strategically placed in key areas of the water-cooled plate to collect real-time and accurate temperature data at each point. This real-time data is fed back to the zoned PID control system as input to the control algorithm. Thermocouples can be surface-mounted, directly contacting the surface of the water-cooled plate to obtain precise surface temperature; or they can be embedded, inserting thermocouple probes into specific holes in the fixture or water-cooled plate to monitor the internal temperature. Through the coordinated monitoring of multiple thermocouples, the temperature distribution of the water-cooled plate can be comprehensively understood, providing a reliable basis for zoned PID control.

[0047] In this embodiment, a heating fixture is used to preheat the water-cooled plate, providing stable and efficient heat transfer to ensure that the water-cooled plate reaches the required temperature before adhesive application. Based on this, combined with zoned PID control and thermocouple monitoring, precise management of the water-cooled plate's temperature field is achieved. Zoned PID control can independently adjust the heating power based on real-time temperature feedback from different areas of the water-cooled plate, effectively compensating for local temperature differences caused by variations in workpiece geometry or heat conduction, thereby controlling the overall temperature uniformity within a very small range of ≤±2℃. Thermocouple monitoring provides high-precision closed-loop feedback data for the PID control system, ensuring that the heating process is always under control, and enabling timely capture and dynamic correction of temperature fluctuations. This precise temperature uniformity ensures a consistent curing rate of the subsequent structural adhesive across the water-cooled plate surface, effectively avoiding localized differences in bond strength or thermal stress concentration caused by uneven temperature, thus significantly improving the battery box's sealing performance and structural stability, and providing an ideal and stable process window for subsequent adhesive application.

[0048] Specifically, in step S3, the water-cooled plate is heated to 50-60℃. Under preheating conditions, two adhesive-applying robots work synchronously, completing the application of all potting compound within 45 seconds. Preheating reduces the adhesive viscosity, improves fluidity, and increases the accuracy of the application trajectory, achieving a CPK ≥ 1.33. The coated components are then transferred to the subsequent pressing station, where the heating plate continues to maintain the temperature for approximately 15 minutes, allowing the adhesive to reach its initial curing strength. Then, the potting compound is manually or visually inspected to confirm the absence of bubbles, insufficient adhesive, and excess adhesive. A temporary protective cover is installed to protect the surface of the water-cooled plate. Components that pass inspection are transferred to the next station, while defective components are diverted to the offline rework area.

[0049] In this step, thermally conductive silicone grease pads are used on the contact surfaces between the fixture and the workpiece to improve heat transfer efficiency. The fixture is equipped with thermocouple sockets for real-time monitoring of the workpiece surface temperature. Heating elements are controlled independently in zones, and a PID algorithm maintains stable temperature.

[0050] Preheating activation reduces the initial curing time of potting compound from 4 hours to 15 minutes, eliminating the need for waiting in the main line; preheating reduces adhesive viscosity, preventing stringing and bubbles, and significantly improving coating quality; overall energy consumption is reduced by approximately 40% compared to oven drying.

[0051] Synchronous operation of two adhesive-applying robots refers to using two independent robotic devices to simultaneously or sequentially apply potting compound to the battery box assembly through preset programs and path planning. For example, a parallel operation can be used, with two robots each responsible for different areas or sides of the battery box's water-cooling plate, applying compound synchronously, thus significantly reducing the overall compounding time. Alternatively, a sequential relay operation can be used, where one robot completes a portion of the compounding, and the other immediately takes over to complete the remaining portion, ensuring the continuity and efficiency of the compounding process, especially suitable for complex or long compounding paths. Furthermore, a master-slave collaborative mode can be used, with one robot acting as the master and the other as the slave, jointly completing a complex compounding path, such as in corners or irregularly shaped areas. Precise path planning and synchronous control ensure a smooth and uniform compounding trajectory.

[0052] Thermal curing, which involves maintaining a temperature of 60°C for 15 minutes using a heating plate at the subsequent lamination station, means that after the potting compound is applied, the workpiece does not need to be transferred to a separate curing device. Instead, the battery box assembly is directly heated and maintained at 60°C in the subsequent lamination station using a heating plate. For example, the heating plate can directly contact the battery box assembly, heating it to 60°C and maintaining it for 15 minutes through heat conduction to promote the initial curing of the potting compound. The heating plate can use resistance wire heating, hot oil circulation heating, or steam heating, and is equipped with a temperature sensor and PID controller for precise temperature control. In addition, the lamination station can also integrate an infrared heater or a hot air circulation system to provide auxiliary radiant heating to the battery box assembly, ensuring temperature uniformity in the potting compound area, especially in complex structures or areas difficult to directly contact.

[0053] In this embodiment, two dispensing robots work collaboratively, significantly improving the coating efficiency of the potting compound. This ensures that the coating is completed within the 45 seconds specified in step S3, effectively avoiding problems such as changes in adhesive viscosity, poor leveling, or premature curing caused by excessive time spent on a single machine. This guarantees the uniformity and filling quality of the potting compound. Simultaneously, the heating plate at the subsequent pressing station provides 60°C for 15 minutes of heat preservation and curing, achieving a tight integration of the initial curing of the potting compound and the subsequent pressing process. This eliminates the need for separate curing equipment, saving equipment investment and space, reducing the number of workpiece handling operations, and minimizing heat loss. This integrated heat preservation and curing method ensures that the potting compound completes its transformation from liquid to solid under controlled temperature conditions, achieving an initial curing strength of 3MPa. This effectively improves the bonding reliability and sealing stability of the internal components of the battery box, ultimately guaranteeing the overall performance and service life of the new energy vehicle battery box.

[0054] Specifically, in step S4, applying structural adhesive to the bottom plate of the battery box includes: placing the bottom plate on the adhesive application fixture and automatically clamping and positioning it; applying structural adhesive 9050L around the perimeter on the upper surface of the bottom plate, with the adhesive line parameters being the same as at station 4, and using a laser sensor to detect the continuity of the adhesive line.

[0055] The process of spraying expanding foam onto the back of a water-cooled plate includes: placing the water-cooled plate assembly on a spraying fixture; using a robot-controlled spray gun to spray expanding foam RUHL350 and RUHL900 onto a designated area on the back of the water-cooled plate, achieving a coverage rate of ≥80%, uniform coating thickness of approximately 3mm; and using a vision system to monitor the coverage rate in real time, automatically respraying or triggering an alarm if the coverage rate is insufficient. The mixing ratio of the two-component expanding foam RUHL350 and RUHL900 is 100:120, the raw material temperature is controlled at 28±3℃, and the spray gun pressure is 0.5-0.8MPa.

[0056] Among them, RUHL350 adhesive comes from RUHL PUROMER GmbH in Germany, model number purogre® 569 / 1L IT RG 350, which is a polyol formulation; RUHL900 adhesive comes from RUHL PUROMER GmbH in Germany, model number purogre® 900, which is a low viscosity, standard functionality polymeric diphenylmethane diisocyanate (MDI).

[0057] Two-component polyurethane foam is a foaming material formed by the reaction of isocyanate and polyol components. Through a chemical reaction, it generates gas, causing the material to expand and solidify, forming a foam with a closed-cell or open-cell structure. Due to its excellent sealing, thermal insulation, cushioning, and good adhesion to various substrates, this material is often used in applications requiring high sealing and structural strength, such as automotive battery boxes. In practical applications, two-component polyurethane foam products from different suppliers can be selected. For example, products with rapid foaming and curing characteristics can be chosen to suit production cycles, or products with higher temperature resistance and chemical corrosion resistance can be selected to improve the long-term reliability of the battery box.

[0058] A two-component mixing ratio of 100:120 refers to the mass or volume ratio of the two components of the foam when mixed. Precise control of the mixing ratio is crucial to ensuring complete polyurethane foaming, uniform foam quality, and stable final product performance. This ratio directly affects the curing speed, expansion ratio, cell structure, density, and ultimately, the mechanical and sealing properties of the foam. The mixing ratio can be controlled using a high-precision metering pump system. For example, a gear pump or plunger pump can be used to independently meter the two components, with flow sensors monitoring and providing feedback adjustments in real time to ensure the accuracy of the mixing ratio. Alternatively, a static or dynamic mixer can be used to precisely dispense the two components in a preset ratio before mixing.

[0059] The raw material temperature is controlled at 28±3℃, referring to the temperature of the two components of the foam adhesive before mixing and spraying. The viscosity, reactivity, and foaming kinetics of polyurethane foam adhesive are highly sensitive to temperature. Controlling the raw material temperature within a specific range ensures a stable viscosity of the adhesive, facilitating pumping and spraying, while also guaranteeing consistent initiation conditions for the foaming reaction, resulting in uniform foaming and stable curing performance. Raw material temperature control can be achieved through storage tanks equipped with heating or cooling devices. For example, the storage tank can have built-in heating rods or cooling coils, and the internal temperature can be monitored in real time by a temperature sensor, combined with a PID controller for precise adjustment. Furthermore, the delivery pipeline can also employ heating or insulation measures to maintain the temperature stability of the adhesive during delivery.

[0060] The spray gun pressure of 0.5-0.8 MPa refers to the pressure of the expanding foam when it is sprayed through the spray gun. Spray gun pressure is a crucial parameter affecting the atomization effect, spray flow rate, coating uniformity, and adhesion of the expanding foam. Appropriate spray gun pressure ensures that the adhesive is sprayed out in a uniform atomized state, forming a continuous and consistent coating, avoiding defects such as sagging, accumulation, or uneven spraying. Spray gun pressure can be controlled through a high-pressure pump and pressure regulating valve. For example, a high-pressure pump driven by a servo motor can provide a stable adhesive supply pressure, combined with a precision pressure sensor and proportional valve for closed-loop control, ensuring accurate and stable spray gun outlet pressure; alternatively, an intelligent spray gun system with built-in pressure sensing and adjustment functions can be used.

[0061] The 3mm coating thickness refers to the thickness of the adhesive layer formed after the expanding foam is sprayed onto the back of the water-cooled plate. Precise control of the coating thickness is crucial for ensuring the sealing performance, expansion ratio, and final structural strength of the expanding foam. An excessively thin coating may lead to sealing failure or insufficient strength, while an excessively thick coating results in material waste and increased weight of the battery box. Coating thickness control can be achieved in several ways. For example, combining a high-precision adhesive application robot with path planning and speed control ensures the accuracy of the spraying trajectory and flow rate. Alternatively, laser displacement sensors or vision inspection systems can be used to detect the coating thickness in real-time or offline, and the adhesive application parameters can be adjusted based on the detection results.

[0062] In this embodiment, by precisely controlling the type, mixing ratio, raw material temperature, spray gun pressure, and coating thickness of the two-component polyurethane foam, the problems of uneven curing, inconsistent density, or sealing performance failure of the foam can be effectively solved. Specifically, a two-component polyurethane foam is selected, and its mixing ratio is precisely set to 100:120 to ensure the stoichiometric balance of the foaming reaction, thereby obtaining an ideal cell structure and stable mechanical properties. At the same time, the raw material temperature is precisely controlled at 28±3℃, effectively eliminating the influence of ambient temperature fluctuations on the viscosity and reactivity of the adhesive, ensuring good flowability and controllable reaction rate of the adhesive during mixing and spraying. Furthermore, by limiting the spray gun pressure to 0.5-0.8MPa, precise atomization and uniform spraying of the adhesive are achieved. Combined with strictly controlling the coating thickness to 3mm, this ensures that the foam forms a uniform and dense sealing layer on the back of the water-cooled plate. The coordinated control of these parameters fundamentally avoids foaming quality defects caused by fluctuations in process parameters, significantly improves the overall structural strength and airtightness of the battery box, and provides a solid guarantee for subsequent heating and pressurization curing and the quality of the final product.

[0063] Specifically, in step S5, the robot assembles the water-cooled plate assembly coated with expanding foam with the base plate and sends it into the pressing machine. The lower mold is heated to 80°C. The upper mold hydraulic cylinder drives the pressure plate downward to apply 10T pressure. The pressure is maintained for 10 minutes, during which heating continues. After the pressure maintenance ends, the hydraulic cylinder is depressurized, the upper mold rises, and the robot removes the cured assembly.

[0064] The lower mold section in this step serves as the fixed side and includes a support platform with a heating plate. The heating plate is embedded with multiple independently controlled electric heating tubes and a PT100 temperature sensor. The surface of the support platform is covered with a thermally conductive aluminum alloy plate and is equipped with floating positioning pins that match the positioning holes of the base plate.

[0065] The upper mold section in this step, serving as the movable side, includes a pressure plate. The lower surface of the pressure plate is coated with a high-temperature resistant polyurethane elastic layer to prevent damage to the workpiece surface. The pressure plate is driven by a servo hydraulic cylinder with a maximum pressure of 10 tons and adjustable stroke. The hydraulic cylinder incorporates pressure and displacement sensors.

[0066] The control system in this step includes a PLC that receives temperature sensor signals and uses a PID algorithm to control the power of each heating zone, stabilizing the temperature of the support platform at the set value. Simultaneously, it monitors the hydraulic cylinder pressure and time, generating a process curve record.

[0067] This integrated curing technology aims to combine the two key process steps of heating and pressurization into a single device for simultaneous execution. Its core principle is to avoid temperature fluctuations and pressure unevenness caused by workpiece transfer or environmental changes in traditional step-by-step processing methods, thus ensuring that the adhesive remains under controlled temperature and pressure fields throughout the heat curing process. This can be achieved, but is not limited to, using a pressing mold with integrated heating elements, or a hydraulic press that circulates the heating medium inside the pressure plate. The lower heating plate, as the main heating unit, provides a precise and uniform temperature environment for the workpiece to be cured. Heating the workpiece to 80°C aims to activate the adhesive's curing reaction and optimize its rheological properties, ensuring that the adhesive fully fills the gaps and effectively wets the substrate. Temperature control is typically achieved through real-time monitoring using embedded thermocouples, combined with closed-loop regulation using a PID controller to ensure temperature uniformity and prevent localized overheating or underheating. The upper pressure plate applies precise pressure to the workpiece. Descending at a speed of 0.5 mm / s, it aims to make smooth contact with the workpiece, avoiding impact and ensuring uniform stress on the workpiece throughout the pressing process. Applying 10 tons of pressure effectively suppresses thermal deformation of large, thin-walled aluminum parts during the heating and curing process, while ensuring the adhesive adheres tightly to the bonding surface under sufficient pressure, expelling air bubbles, and thus forming a high-strength bond. Pressure application is typically achieved through a hydraulic system or servo electric cylinder, with real-time feedback and control provided by a high-precision pressure sensor. The holding time refers to the duration of maintaining the preset temperature and pressure. Setting it to 10 minutes allows the adhesive sufficient time for curing, enabling it to complete initial curing under optimal temperature and pressure conditions, forming stable physical and chemical bonds, thereby achieving sufficient initial strength to withstand subsequent handling and processing. This time is precisely timed by the control system to ensure process consistency. Furthermore, real-time recording of temperature and pressure curves is crucial for process monitoring and quality traceability. By continuously collecting and storing data from temperature and pressure sensors during the curing process, a complete historical record of process parameters can be created. This not only helps verify whether each workpiece is cured according to the predetermined process parameters but also provides important evidence for process optimization, fault diagnosis, and product quality traceability. Data recording systems typically employ industrial computers or PLCs in conjunction with data acquisition modules, and can store data in local or cloud databases.

[0068] In this embodiment, the heating and pressurizing processes are integrated into the same device and executed synchronously. This effectively solves the problem of thermal warping deformation of large thin-walled aluminum parts caused by the independent or improperly controlled heating and pressurizing processes in traditional step-by-step processing methods, as well as the difficulty in ensuring the consistency of the temperature and pressure fields during adhesive curing. The lower heating plate precisely heats the workpiece to 80°C, ensuring that the adhesive is uniformly activated and cured at the optimal temperature, avoiding local overheating or underheating, thereby improving the curing quality. The upper pressure plate descends at a controlled speed of 0.5 mm / s and applies a constant pressure of 10 tons, which effectively suppresses the thermal expansion and deformation of the workpiece during the heating process, ensuring that the battery box base plate and water-cooled plate assembly maintain high precision and flatness during the curing process, significantly improving the final assembly accuracy. The 10-minute pressure holding time ensures that the adhesive is fully cured under ideal conditions, forming a strong bond. In addition, the temperature and pressure curves are recorded in real time during the curing process, enabling closed-loop monitoring and data traceability of the entire curing process. This ensures that the process parameters of each product are under control, greatly improving the structural reliability and quality consistency of the battery box assembly in multi-model mixed-line production.

[0069] Specifically, in step S6, the solidified product is placed into the three-dimensional buffer warehouse by the robot, and the control system records the entry time and vehicle model information of each product. The buffer warehouse is managed according to the first-in-first-out logic to ensure that each workpiece stays in the warehouse for ≥90 minutes. After the dwell time is reached, the robot takes out the workpiece with the longest dwell time first and transports it to the downstream airtightness testing station.

[0070] The buffer warehouse uses a steel-framed automated storage and retrieval system. The floor height is designed to be 200mm, based on the product thickness of approximately 144mm plus a safety clearance. 90 minutes ÷ 920 seconds / piece ≈ 5.87 pieces, rounded to 6. Therefore, a design capacity of 6 pieces is sufficient to meet the 90-minute buffer requirement. This embodiment uses 12 bays, arranged in 2 columns × 6 layers, providing redundant capacity. Each bay is equipped with an independent removable pallet, and the buffer warehouse entrance and exit are located on the same side.

[0071] The storage and retrieval process is equipped with a dedicated six-axis robot, with a retractable double-fork pick-and-place tool as the end effector. The robot's range of motion covers all locations in the buffer warehouse, as well as the upstream unloading station and the downstream picking station.

[0072] The asynchronous buffer cooling system employs a first-in-first-out (FIFO) three-dimensional buffer to automate and manage the workpiece cooling process. This buffer can be implemented in various ways. For example, it can be a system consisting of multi-layer racks and automated shuttles, where the shuttles automatically store and retrieve workpieces according to a pre-defined FIFO logic. Alternatively, it can be a gravity- or mechanically driven roller-type multi-layer rack system, where workpieces enter from one end and are retrieved sequentially from the other, naturally following the FIFO principle.

[0073] The three-dimensional buffer library has a capacity of at least six workpieces, providing the necessary buffer space for the production line. This capacity design can be adjusted according to actual production needs. For example, through modular design, additional storage units can be added to the basic capacity; or, through flexible bay configuration, a single bay can accommodate workpieces of different sizes, thereby achieving effective storage of at least six workpieces within the physical space.

[0074] To ensure each workpiece receives sufficient cooling time, a timestamp is recorded upon entry into the warehouse, and it can only be retrieved after a dwell time of 90 minutes or more. This can be achieved through various technological means, such as equipping each workpiece with an RFID tag or barcode, which is read and the time information is recorded to the central control system upon entry; or, a visual recognition system combined with artificial intelligence algorithms can automatically identify workpieces and record their entry time. The control system will then precisely manage workpiece retrieval permissions based on these timestamps, ensuring the integrity of the cooling and curing process.

[0075] The cache library utilizes a steel frame with a 200mm ceiling height, designed to provide a robust and stable storage environment and optimize space utilization. The steel frame can withstand the weight of the battery compartment components, ensuring structural stability during long-term operation. The 200mm ceiling height maximizes vertical space utilization and minimizes the floor space while ensuring easy access to components. This steel frame can be constructed using a welded structure for maximum rigidity or a modular, bolted structure for ease of installation, maintenance, and future expansion.

[0076] In addition, each compartment is equipped with an independent retractable tray, which greatly facilitates the automated storage, retrieval, and protection of workpieces. These trays can be designed with casters at the bottom for push-pull operation via automated robotic arms or shuttles; alternatively, the trays can be mounted on sliding rails for precise telescopic movement via servo motors or pneumatic devices. This independent tray design not only effectively prevents workpieces from being bumped or deformed during storage and retrieval but also ensures the independence and stability of each workpiece during buffering.

[0077] In this embodiment, a highly efficient and reliable asynchronous buffer cooling system was constructed. By introducing a first-in-first-out (FIFO) three-dimensional buffer library, this system effectively resolves the conflict between long-duration cooling processes and production line cycle time, decoupling the cooling process from the main production line and avoiding low production efficiency caused by online waiting. Precise timestamp recording and dwell time control ensure that each battery box component has reached sufficient cooling and curing strength before entering subsequent testing or assembly stages, thereby significantly improving product quality consistency and reliability. Simultaneously, the steel structure and independent removable tray design not only guarantee storage stability and space utilization but also optimize automated handling and protection of components, providing solid quality assurance and production efficiency support for the multi-model flexible adhesive bonding method for new energy vehicle battery boxes.

[0078] Specifically, in step S7, the airtightness test of the foam area includes: the robot places the cooled product at the airtightness test station and automatically seals all openings of the tooling to seal the battery box; compressed air is injected into the foam cavity through the air inlet to a set pressure of 10kPa±0.5kPa, the pressure is maintained for 60 seconds, and the pressure drop ΔP is measured; if the leakage rate is ≤1.5cc / min, it is qualified, and the test result is uploaded to MES in real time; otherwise, it is sent to the offline rework area.

[0079] The airtightness test of expanded polystyrene (EPS) areas employs the differential pressure method. This method determines the sealing performance by measuring the pressure difference between the inside and outside of the tested object. When a leak occurs, the internal pressure of the tested object changes, resulting in a change in the pressure difference between it and a reference chamber. This method can detect minute gas leaks with high sensitivity and is suitable for components with high sealing requirements. For example, the EPS area to be tested can be sealed in a test chamber, and then gas at a certain pressure can be introduced into the chamber. A reference chamber is also set up, and the pressure difference between the test chamber and the reference chamber is monitored in real time using a high-precision differential pressure sensor. Alternatively, a vacuum differential pressure method can be used, which involves evacuating the test chamber and then monitoring the pressure difference between it and the external environment or a reference vacuum chamber.

[0080] The test pressure is set at 10 kPa ± 0.5 kPa to ensure the stability and repeatability of the testing environment, avoid misjudgments caused by pressure fluctuations, and simulate the pressure conditions under actual working conditions, making the test results more representative. This can be achieved through a closed-loop control system composed of a high-precision pressure regulating valve and a pressure sensor, which monitors and adjusts the inflation pressure in real time to keep it stable within the target range. Alternatively, a preset pressure source and pressure relief valve combination can be used to maintain pressure stability by precisely controlling the pressure relief rate after inflation reaches the set value.

[0081] The holding pressure time is set to 60 seconds. Its function is to give enough time for gas to penetrate in the possible tiny leakage paths, so that the pressure change can be effectively captured by the sensor, thereby improving the accuracy and sensitivity of detection. This can be achieved by a programmable logic controller or an industrial computer to control the timer. After reaching the set test pressure, the timer starts counting, and data collection and judgment are carried out after the counting ends. Or, precise holding pressure time control can also be achieved through a dedicated control module integrated in the airtight detection device.

[0082] A leakage rate ≤ 1.5 cc / min is considered qualified. This standard sets a clear quantitative qualification standard to distinguish qualified products from unqualified products, ensures that the product sealing performance meets the design requirements, and provides a basis for subsequent quality control and repair. The detection system can automatically calculate the leakage rate based on the pressure difference change during the holding pressure time, combined with parameters such as the test cavity volume, and compare it with the preset qualified threshold.

[0083] Unqualified parts are sent to the offline repair area. This measure aims to timely divert unqualified products from the production line to avoid wasting resources in subsequent processes. At the same time, it is convenient for centralized defect analysis and repair, improving production efficiency and product quality. This can be achieved through an automated sorting mechanism, such as a robotic arm, a push rod or a conveyor belt diversion device. After the detection result is determined to be unqualified, the workpiece is automatically transferred to the designated offline repair area.

[0084] In this embodiment, by using the differential pressure method to conduct airtight detection on the foaming glue area, this application can highly sensitively identify tiny leaks in the foaming glue area of the battery box, effectively solving the problem that traditional detection methods are difficult to detect hidden defects. The test pressure is precisely set to 10 kPa ± 0.5 kPa, ensuring the stability of the detection process and the reliability of the results, and avoiding misjudgment caused by pressure fluctuations. The 60-second holding pressure time provides sufficient time for gas penetration, enabling even extremely tiny leaks to be accurately captured, significantly enhancing the detection sensitivity. Taking the leakage rate ≤ 1.5 cc / min as the qualified standard provides a clear quantitative basis for product quality, ensuring that the sealing performance of the battery box meets the design requirements. In addition, unqualified parts are automatically diverted to the offline repair area, realizing the preposition of quality control, avoiding unqualified products from entering subsequent high-value-added processes, thereby effectively reducing production costs and rework risks, and improving the overall production efficiency and product consistency. This detection scheme combined with the aforementioned multi-model flexible glue coating method for the battery box further improves the quality reliability of the battery box while ensuring production flexibility.

[0085] Specifically, in step S8, the assembly of the longitudinal beam, the cross beam, and the sleeve includes: the robot grabs the pre-processed longitudinal beam, applies structural adhesive to the contact surface between the longitudinal beam and the cold plate, installs the longitudinal beam onto both sides of the cold plate, and automatically tightens the bolts; the cross beam is installed onto the cold plate, the sleeve is placed in the designated position, the servo press presses the sleeve in, and an alarm is triggered when the pressing force exceeds the threshold, and the workpiece is diverted to the rework area.

[0086] The sleeve airtightness test includes: placing the product at the testing station, sealing each sleeve with a flexible sealing head, measuring leakage using the differential pressure method, and setting the test pressure according to the sleeve specifications. If the leakage rate is ≤0.5cc / min, it is qualified; otherwise, it is sent to the offline rework area.

[0087] In this step, foam leakage is screened out at an early stage, avoiding subsequent costs for assembly and gluing; regional detection can directly pinpoint the source of leakage, and rework does not require complete disassembly. Defective parts are automatically diverted to the offline line without affecting the continuity of the main line.

[0088] The sleeve airtightness test employs the differential pressure method. The differential pressure method is a highly sensitive airtightness testing technique. Its principle is to determine the presence of a leak by measuring the change in the difference between the internal pressure of the sleeve assembly under test and a reference pressure. This method effectively eliminates the interference of external factors such as ambient temperature and atmospheric pressure fluctuations on the test results, thus significantly improving the accuracy and stability of the test. In practice, the sleeve assembly under test can be sealed and filled with gas at a certain pressure, while simultaneously connecting a reference chamber of known volume. Both chambers are connected to a differential pressure sensor. If a leak exists in the sleeve, its internal pressure will drop, causing a change in the pressure difference between the sleeve assembly and the reference chamber, which the differential pressure sensor can detect. Alternatively, the sleeve assembly under test can be sealed and filled with gas at a certain pressure. A high-precision differential pressure sensor can be used to monitor the minute changes in the internal pressure of the tested component relative to the initial pressure in real time. By setting a pressure holding time, the pressure drop per unit time can be calculated, and the leakage rate can be deduced.

[0089] The test pressure is set according to the sleeve specifications. Since different models or specifications of sleeves differ in size, material, structural design, and expected pressure capacity, the test pressure needs to be set specifically for each. This differentiated testing strategy ensures the effectiveness and safety of the test, fully exposing potential leaks while avoiding unnecessary damage to the sleeve due to excessive pressure. For example, the control system can preset a database or lookup table storing recommended test pressure values ​​for different models or specifications of sleeves. When the sleeve specification of the current workpiece is identified, the system automatically retrieves the corresponding test pressure parameters from the database. Alternatively, the sleeve specification can be obtained by manual input or scanning of workpiece information, and then the operator or the system can dynamically adjust the test pressure according to empirical formulas, design specifications, or preset pressure curves.

[0090] A leakage rate ≤ 0.5 cc / min is considered qualified. Setting a clear qualified leakage rate threshold is the key to quantifying the airtightness detection results. It provides an objective and quantifiable standard for judging whether the sleeve assembly meets the design requirements, thus ensuring the consistency of product quality. During the detection process, the system will calculate or estimate the leakage rate of the measured sleeve in real time. When the calculated leakage rate is less than or equal to 0.5 cc / min, the system determines that the airtightness of the sleeve assembly is qualified. This threshold can be determined by comparing and calibrating with a standard leakage component or by precisely measuring the volume of leaked gas with a flow meter. The software logic inside the detection equipment continuously monitors the differential pressure change, converts it into a leakage rate, and then compares it with this threshold.

[0091] Unqualified parts are sent to the offline repair area. This step is an important part of defect management and quality control, aiming to isolate unqualified products in a timely manner, prevent them from flowing into subsequent processes, reduce production waste, and provide a dedicated area for repair. When the detection system determines that the sleeve assembly is unqualified, it will automatically trigger the diversion mechanism to transfer the unqualified workpiece from the main production line to the preset offline repair area. At the same time, the system will record the unqualified information for subsequent traceability and analysis, providing data support for process improvement.

[0092] In this embodiment, after the longitudinal beam, cross beam, and sleeve of the battery box are assembled, a special airtightness detection is immediately carried out on the sleeve, achieving precise control over the installation quality of the key structural components of the battery box. Using the differential pressure method for detection can effectively eliminate the interference of environmental fluctuations on the measurement results and improve the sensitivity and stability of the detection. Setting the test pressure according to the sleeve specifications reflects a differential detection strategy for different vehicle models or different structural parts, ensuring the matching of detection parameters with the actual working conditions. By setting a clear qualified threshold for the leakage rate, sleeve assemblies with unqualified sealing performance can be quickly identified. Automatically diverting unqualified parts to the offline repair area realizes the early interception and closed-loop processing of defects, avoids unqualified products from flowing into subsequent high-value-added processes, effectively reduces the quality risk and repair cost in the overall production process, and improves production efficiency and product quality.

[0093] Specifically, in step S9, the workpiece is automatically positioned, the detection program is started, and 144 CCD cameras are used to respectively photograph the four quadrants of the workpiece, covering all key installation points. The 144 CCD cameras are installed on the gantry above the workpiece, covering the four quadrants of the workpiece. The camera pixels are ≥ 5 million, the lens distortion is ≤ 0.1%, and the CCD cameras are equipped with ring lights to ensure uniform illumination.

[0094] The detection software compares the measured dimensions with the CAD theoretical dimensions and outputs the deviation value. The detection contents include: the position degree of key installation holes, the outline dimensions, the width and continuity of the glue application trajectory, and the detection time is ≤ 130 seconds per piece.

[0095] This step utilizes 144 high-resolution CCD cameras to perform full-size inspection of the battery box. A CCD camera is an imaging device that converts optical images into electrical signals through photoelectric conversion, and then into digital signals for processing. High resolution means it can capture finer image details. By evenly distributing the 144 cameras in an array layout across multiple dimensions of the battery box inspection area, including above and to the sides, and employing a synchronous triggering mechanism to acquire images simultaneously, multi-angle, omnidirectional image acquisition of large battery boxes can be achieved, ensuring no blind spots in the inspection. In other implementations, a modular design can be used, grouping the cameras and rapidly switching or moving them via robotic arms or guide rail systems to cover the entire battery box, but the inspection efficiency must be ensured to meet requirements.

[0096] Furthermore, the camera resolution should be at least 5 megapixels. A pixel is the smallest unit of a digital image; the more pixels, the stronger the image's detail representation. Using an industrial-grade CCD sensor with 5 megapixels or higher, such as the CMOS ISCMV50000 sensor or the Sony IMX series sensors, ensures that the acquired images have sufficient detail to accurately identify minute dimensional deviations, positional errors, and subtle defects in adhesive application. In some implementations, image stitching technology can also be used to fuse images captured by multiple lower-resolution cameras to achieve an equivalent resolution of 5 megapixels or even higher.

[0097] Meanwhile, lens distortion is ≤0.1%. Lens distortion refers to the phenomenon where the image does not match the actual shape of the object during imaging by an optical system, usually manifested as barrel distortion or pincushion distortion. A distortion rate of ≤0.1% indicates excellent optical performance and minimal image distortion. By selecting high-quality, low-distortion industrial-grade fixed-focus lenses, which typically employ multi-element aspherical lens designs and undergo precise optical correction, the geometric accuracy of the image can be guaranteed, avoiding inaccurate measurement results due to lens distortion, which is especially crucial for size and position measurement. In other implementations, software correction algorithms can also be used to correct image distortion, but this method increases computational load, and the correction effect is limited by the algorithm's accuracy and the original degree of distortion.

[0098] To meet production cycle time requirements, the inspection time is controlled to within 130 seconds per piece. Inspection time refers to the maximum time required to complete all specified inspection items for a single battery box. To achieve this goal, this application employs multi-camera parallel acquisition and multi-core processor parallel image processing technology, simultaneously analyzing images from different regions. Furthermore, by optimizing the image processing algorithm and employing a fast recognition and measurement model based on deep learning, computation time can be reduced.

[0099] The inspection includes the positional accuracy of key mounting holes, the overall dimensional dimensions, and the quality of the adhesive application path. These are critical quality control indicators in the battery box manufacturing process. For the positional accuracy of key mounting holes, the center point is identified through image recognition and compared with the CAD model to calculate the positional deviation. For the overall dimensional dimensions, the contour lines are extracted using edge detection algorithms and fitted and compared with standard contours to measure dimensional deviations. For the adhesive application path quality, grayscale analysis and texture recognition technologies are used to detect the width, height, and continuity of the adhesive lines, and to identify defects such as bubbles and breaks. This comprehensive assessment of the battery box's manufacturing precision and bonding quality ensures it meets subsequent assembly and usage requirements.

[0100] In this embodiment, a large-scale, high-resolution visual inspection system was constructed, enabling precise monitoring of the entire size and adhesive coating quality of the battery box. 144 high-resolution charge-coupled device (CCD) cameras ensure comprehensive coverage of all key components of the large battery box, effectively solving the problem of missed detections caused by limited field of view in traditional inspection methods. Simultaneously, using cameras with at least 5 megapixels and lenses with extremely low distortion rates, minute dimensional deviations and adhesive coating trajectory anomalies can be captured, providing high-precision raw data support. Under the condition of a limited inspection time of no more than 130 seconds per piece, through multi-camera collaborative operation and efficient image processing, a comprehensive, rapid, and high-precision assessment of the positional accuracy of key mounting holes, external dimensions, and adhesive coating trajectory quality is achieved while maintaining production cycle time. This allows for the timely detection of minor assembly deviations or adhesive coating defects, effectively preventing them from adversely affecting the assembly accuracy and overall airtightness of subsequent processes. Furthermore, this high-precision detection data can serve as the basis for dynamically compensating the previous coating or positioning parameters in step S9, forming a closed loop of quality control. This significantly improves the quality stability and production efficiency of the entire flexible coating assembly method for multi-model new energy vehicle battery boxes, and effectively reduces rework costs caused by delayed defect detection.

[0101] The following example will provide a more detailed explanation of the above technical solution: In a new energy vehicle battery box manufacturing plant, battery boxes for multiple different car models need to be produced simultaneously, such as the EB5X5 and EB5Y5 models. These battery boxes differ in length but have similar widths, and the manufacturing process involves the application of various adhesives, such as structural adhesives, potting compounds, and foaming agents, each with different application and curing conditions.

[0102] First, when a battery box workpiece enters the production line, the system automatically identifies the vehicle model of the workpiece by scanning the QR code or RFID tag on it, for example, identifying it as model EB5X5. Based on the identification result, the control system retrieves the positioning coordinates corresponding to model EB5X5 from a pre-stored positioning coordinate database. Subsequently, servo motors drive the flexible positioning pins at each station to move precisely along the guide rails to the target position of model EB5X5. Displacement sensors provide real-time feedback on the actual position of the positioning pins, and the positioning pins are locked when the deviation between the actual position and the target position is less than or equal to ±0.05mm. The entire changeover process is completed within 3 seconds, thus enabling rapid switching between battery boxes of different models and flexible co-line production, effectively solving the problems of time-consuming changeovers and low equipment utilization in traditional production lines.

[0103] Next, at the water-cooled plate preheating station, a dedicated heating fixture preheats the battery box's water-cooled plate to 50-60°C. This heating fixture, through zoned PID control and real-time monitoring by multiple thermocouples, ensures that the temperature uniformity of the water-cooled plate surface is less than or equal to ±2°C, avoiding localized overheating or underheating and providing a stable temperature base for subsequent adhesive application. Simultaneously, on the front side of the battery box frame, an adhesive application robot precisely applies structural adhesive.

[0104] Subsequently, the preheated water-cooled plate is assembled with the frame coated with structural adhesive. Maintaining a constant ambient temperature of 53-57℃, two adhesive-applying robots work collaboratively to apply the potting compound within 45 seconds. After application, the workpiece is sent to the subsequent pressing station. At this station, the heating plate maintains the workpiece at 60℃ for 15 minutes before pressing, allowing the potting compound to reach its initial curing strength. This integrated heat preservation and curing method avoids separate curing waiting times, improving production efficiency.

[0105] At the next workstation, structural adhesive is applied to the base plate of the battery box. Simultaneously, a two-component polyurethane foam is sprayed onto the back of the water-cooling plate. The mixing ratio of the two components of this foam is precisely controlled at 100:120, and the raw material temperature is controlled at 28±3℃. The spray gun is used at a pressure of 0.5-0.8MPa to ensure that the coating thickness is precisely controlled at 3mm. This refined foam spraying process guarantees the performance and sealing effect of the foam.

[0106] After the adhesive is coated, the bottom plate and the water-cooled plate assembly are clamped together and enter the heating and pressurizing integrated curing device. In this device, the lower heating plate heats the workpiece to 80°C. At the same time, the upper pressure plate descends uniformly at a speed of 0.5 mm / s and applies a pressure of 10 tons. The pressure holding time is 10 minutes. During the curing process, the system records the temperature curve and the pressure curve in real time to ensure the stability and consistency of the curing process. This integrated curing method effectively solves the problem of thermal warping deformation that is prone to occur during the heating and curing process of large thin-walled aluminum parts, ensuring the final assembly accuracy.

[0107] The cured workpiece is automatically stored in an asynchronous buffer cooling system. This system adopts a first-in-first-out three-dimensional buffer library structure with a capacity of at least 6 workpieces. When each workpiece is put into the library, the system automatically records the timestamp. The workpiece stays in the buffer library for no less than 90 minutes and can be taken out only after being fully cooled and reaching the final curing strength. This buffer library is made of steel structure with a floor height of 200 mm, and each bin is equipped with an independent extractable tray. This asynchronous buffer cooling system decouples the long cooling and curing process from the main production line, avoiding lengthening the overall line cycle due to waiting for cooling, and significantly improving the overall equipment efficiency of the production line.

[0108] The cooled workpiece is first subjected to airtight detection in the foaming glue area. The detection uses the differential pressure method, the test pressure is set at 10 kPa ± 0.5 kPa, and the pressure holding time is 60 seconds. If the leakage rate is less than or equal to 1.5 cc / min, it is judged as a qualified part. Unqualified parts will be automatically diverted to the offline repair area, avoiding the transfer of defects to subsequent processes and reducing the rework cost.

[0109] Subsequently, the erection of the longitudinal beam, cross beam and sleeve is carried out. After the erection is completed, the sleeve is subjected to airtight detection, also using the differential pressure method. The test pressure is set according to the specifications of different sleeves, and the leakage rate less than or equal to 0.5 cc / min is qualified. Unqualified parts are also automatically diverted to the offline repair area. This segmented airtight detection enables the early discovery and handling of defects.

[0110] Finally, all qualified workpieces are subjected to full-size CCD detection. This detection system is equipped with 144 high-resolution CCD cameras, each camera has a pixel greater than or equal to 5 million, and the lens distortion is less than or equal to 0.1%. The detection time is less than or equal to 130 seconds per piece. The detection content includes the position accuracy of key mounting holes, the outline dimensions, and the quality of the glue application trajectory. According to the detection data, the system can dynamically compensate the previous glue application or positioning parameters, forming a closed-loop control, further optimizing the production process, and ensuring the continuous stability and improvement of product quality. This comprehensive online detection and feedback mechanism fundamentally solves the problems of lagging defect detection and high rework cost in traditional production lines.

[0111] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A flexible adhesive coating method for multi-model battery boxes in new energy vehicles, characterized in that, Includes the following steps: S1: Identify the current workpiece model and automatically switch the flexible positioning system of each station to the corresponding positioning coordinates according to the model; S2: Preheat the water-cooled plate of the battery box to 50-60℃ and apply structural adhesive to the front of the frame; S3: Combine the preheated water-cooled plate with the frame, and apply the potting compound within 45 seconds while maintaining an environment of 53-57℃. Then, perform heat preservation and curing to achieve an initial curing strength of 3MPa. S4: Apply structural adhesive to the bottom plate of the battery box and spray foam adhesive on the back of the water-cooling plate. S5: After the base plate and water-cooled plate assembly are molded together, they are heated and pressurized for integrated curing; S6: Store the cured workpiece in the asynchronous buffer cooling system and remove it after staying for no less than 90 minutes; S7: Perform an airtightness test on the foamed area of ​​the cooled workpiece, and automatically divert unqualified parts to the rework area; S8: Assemble the longitudinal beams, transverse beams and sleeves, and perform airtightness testing on the sleeves; unqualified parts are automatically diverted. S9: Perform full-size CCD inspection on qualified workpieces and dynamically compensate for previous adhesive application or positioning parameters based on the inspection data.

2. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S1, the switching method of the flexible positioning system is as follows: the control system stores the positioning coordinates of at least two vehicle models, the servo motor drives the positioning pin to move along the guide rail to the target position, the displacement sensor feeds back the actual position, and the system locks after the deviation is ≤ ±0.05mm, and the model switching time is ≤3 seconds.

3. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S2, the water-cooled plate is preheated using a heating fixture, with temperature uniformity ≤ ±2℃, which is ensured by zoned PID control and thermocouple monitoring.

4. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S3, the potting compound is applied using two coating robots working together; the heat preservation and curing is achieved by using a heating plate at 60°C for 15 minutes in the subsequent pressing station.

5. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S4, the foaming adhesive is a two-component polyurethane foaming adhesive with a two-component mixing ratio of 100:120, the raw material temperature is controlled at 28±3℃, the spray gun pressure is 0.5MPa to 0.8MPa, and the coating thickness is controlled at 3mm.

6. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S5, the integrated heating and pressurization curing process involves simultaneously heating and pressurizing within the same device: the lower heating plate heats the workpiece to 80°C, while the upper pressure plate descends at a speed of 0.5 mm / s and applies 10 tons of pressure for 10 minutes; the temperature and pressure curves are recorded in real time during the curing process.

7. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S6, the asynchronous buffer cooling system adopts a first-in-first-out three-dimensional buffer library with a capacity of at least 6 workpieces. Each workpiece is recorded with a timestamp when it enters the library and can only be taken out after a stay time of ≥90 minutes. The buffer library adopts a steel structure with a floor height of 200mm, and each compartment is equipped with an independent pull-out tray.

8. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S7, the air tightness test of the foam area is performed using the differential pressure method: the test pressure is 10kPa±0.5kPa, the pressure holding time is 60 seconds, and the leakage rate is ≤1.5cc / min to be qualified; unqualified parts are sent to the offline rework area.

9. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S8, the sleeve air tightness test is performed using the differential pressure method. The test pressure is set according to the sleeve specifications, and a leakage rate of ≤0.5cc / min is considered qualified. Unqualified parts are sent to the offline rework area.

10. The flexible adhesive coating method for multi-model new energy vehicle battery boxes according to claim 1, characterized in that, In step S9, the full-size CCD inspection includes: using 144 high-resolution CCD cameras with a camera pixel count ≥ 5 million, lens distortion ≤ 0.1%, and inspection time ≤ 130 seconds / piece, to inspect the position accuracy of key mounting holes, the outer contour dimensions, and the adhesive application trajectory.

Images