Exploring the Technical Features of Heating and Pressure Systems in Laminators

As the core equipment for module encapsulation, the technological iteration of the heating and pressure systems in photovoltaic laminators profoundly impacts module production efficiency, quality and cost. The following is an in-depth analysis of the technical characteristics of these two systems, based on the latest industry developments.

 

 

I. Analysis of the Technical Characteristics of the Heating System

The core task of the heating system is to achieve uniform, efficient, and stable heat transfer, ensuring the full melting and flow of the encapsulating film (EVA/POE/EPE). Its technological evolution is mainly reflected in the following aspects:

1. Heating Method: From Traditional Media to Electromagnetic Induction Revolution

Traditional laminators mostly use heat-conducting oil or resistance wire heating, which suffers from high energy consumption, slow heating, poor temperature uniformity, and complex maintenance.In recent years, electromagnetic induction heating technology has achieved a major breakthrough. This technology integrates an electromagnetic coil inside the heating plate, utilizing the eddy current effect to heat the heating plate itself, completely eliminating the need for heat-conducting media. Its core advantages are:

(1) Significantly improved heating rate: Enables direct and rapid heating, shortening process waiting time.

(2) Significantly improved temperature uniformity: Completely solves problems such as localized overheating and large temperature differences between layers in traditional processes.

(3) Outstanding energy-saving effect: Reduces the energy consumption cost of solar cell modules by approximately 32%.

 

2. Temperature control accuracy: Closed-loop control achieves precise control within ±1℃.

Modern laminators employ multi-zone independent temperature control + intelligent PID closed-loop regulation technology. Multiple temperature sensors (such as thermocouples and RTDs) monitor the temperature of different areas of the heating plate in real time, and the controller dynamically adjusts the power output of the heating elements based on feedback. Currently, mainstream equipment can control the temperature distribution uniformity of the heating plate within ±1.5℃, achieving a temperature control accuracy of ±1℃.

3. Optimized heating plate structure

As the direct carrier of heat transfer, the material and structural design of the heating plate are crucial. High-quality aluminum alloy or alloy materials with excellent thermal conductivity are typically used, with heating pipes or heating elements precisely machined internally. Some advanced designs employ a seamless, weld-free process for integral panel fabrication, eliminating the risk of thermal stress deformation and ensuring consistent flatness and thermal conductivity over long-term use.

4. Integrated Thermal Management System

To meet the demands of continuous production, heating and cooling systems typically work in tandem. After lamination, components need rapid cooling before proceeding to the next process. Modern laminators are often equipped with independent cooling sections, using water or air cooling for rapid cooling, improving overall line speed.

II. Analysis of Pressure System Technical Characteristics

The core task of the pressure system is to provide uniform, adjustable, and stable pressure, ensuring tight bonding of multilayer materials under heating and expelling interlayer gases.

Key technical points include:

1. Pressure Generation Method: A Battle Between Hydraulics and Pneumatics

Currently, most mainstream large laminators utilize hydraulic systems to meet the uniform high pressure required for large-size components (e.g., 182/210mm). Typical operating pressure ranges from -100KPa to 0KPa (vacuum), adjustable.

2. Pressurization Process: From Simple Pressure Application to Three-Stage Intelligent Control

Modern laminators generally employ a three-stage pressurization process:

(1) Pre-pressurization stage: Applying low pressure in a vacuum environment to initially soften the film and expel gas.

(2) Main pressurization stage: Gradually increasing to the set process pressure to achieve tight bonding between materials.

(3) Holding and releasing pressure stage: Maintaining the set pressure for a specified time, followed by controllable pressure release.

This segmented pressurization effectively avoids residual air bubbles and microcracks in the solar cells, making it particularly suitable for ultra-thin, large-size solar cells.

3. Revolutionary Pressure Uniformity: Hard Press Technology Overturns Tradition

Traditional laminators use a soft pressurization process, relying on a silicone plate as a buffer layer to transmit pressure. However, silicone plates have inherent problems such as aging deformation and uneven pressure distribution.

Since 2025, significant breakthroughs have been achieved in flat panel hard-press technology:

(1) Elimination of silicone sheet consumables: Pioneering an integrated hard-press technology, using a rigid pressure system to replace flexible buffers.

(2) 30% improvement in pressure uniformity: Completely solving the problem of edge stress concentration.

Zero puncture of butyl rubber: In heterojunction module testing, the degradation rate caused by butyl rubber puncture has been reduced from 30%.

Significant cost reduction: Annual cost reduction of up to 5 million CNY per GW.

4. Pressure Closed-Loop Control System

Modern laminators are equipped with a closed-loop regulation system consisting of a pressure transmitter and an intelligent controller.

The pressure sensor monitors the chamber pressure in real time and feeds the signal back to the controller; The controller dynamically adjusts the hydraulic pump displacement or pneumatic valve opening based on the deviation between the set value and the measured value. During constant pressure processes, it can automatically compensate for pressure drops, keeping pressure fluctuations within a minimal range.

 

III. Synergy and Integration of the Two Major Systems

The heating and pressure systems of laminator do not work independently but achieve precise synergy through the control system.

1.Timing Synergy: The control system precisely coordinates the start and end times and execution sequence of each stage, such as heating, vacuuming, pressurizing, holding, and cooling, according to a preset process curve.

2.Parameter Linkage: Temperature changes during laminating affect material flowability, thus affecting pressure response; the timing of pressure application affects film flow and gas discharge. Modern equipment achieves multi-parameter linkage optimization of temperature, pressure, and time through a process formula management system.

3.Fault Self-Diagnosis and Early Warning: An integrated intelligent monitoring system monitors key parameters such as heating element status, pressure sensor signals, and vacuum level in real time. It automatically alarms and provides fault diagnosis suggestions when abnormalities occur.

 

IV. Technological Development Trends

The heating and pressure systems of photovoltaic laminators are undergoing profound transformations, from "experience-based control" to "precise intelligent control," from "soft pressure" to "hard pressure," and from "single-machine energy saving" to "system cost reduction." The technological level of these two systems directly determines the quality, efficiency, and cost of module encapsulation, and is a key support for photovoltaic manufacturing to move towards "zero defects and extreme cost reduction."