In recent years, China's thin-film battery production has increased, but due to the cost, large size photoelectric conversion efficiency and technology popularity and other aspects of the limitations, in the overall production of photovoltaic modules accounted for a relatively low. In today's "dual-carbon" and "dual-control of energy consumption" policy context, BIPV (photovoltaic building integration) is an effective way to implement green buildings.
At present, although thin film batteries in the conversion efficiency is not as good as crystalline silicon batteries, but its simple structure, adjustable light transmittance, low light, temperature coefficient is small and other characteristics, making thin film batteries in the BIPV than crystalline silicon batteries have more advantages, thin film batteries can be better combined with building materials, is expected to occupy a place in the market. Especially in the past two years, the development of calcium titanium ore battery by the market attention, has gradually opened the process of mass production.
Chalcogenide photovoltaic cells, the use of chalcogenide-type compounds as light-absorbing materials, compared to crystalline silicon and other thin-film batteries, chalcogenide photovoltaic cells have the following advantages:
Chalcogenide is a synthetic material and the band gap can be adjusted depending on the formulation;
Advantages of high conversion efficiency and power generation, stacking more efficiency development potential;
Simple preparation process, short process, high production efficiency, low material cost, no high temperature production, energy saving;
Good low light and light transmission, appearance and morphology can be adjusted in a wide range, lightweight and flexible features make the application of calcite batteries in a wider range of scenarios.
Application of laser in the production of chalcogenide
In the single-junction chalcogenide battery preparation process, there are four laser processes, which need to be carried out three times parallel laser etching laser to make the material vaporization and formation of groove lines, the whole film layer is divided into a series of each other's sub-cells of about 4-12mm wide, thus forming a blocking the current conduction of the individual modules, in order to achieve the effect of increasing the voltage and the series of the battery. The last process is to remove the film layer of about 10mm width against the edge of the glass to form an insulated area for the back-end encapsulation area.
- Laser etching of the bottom TCO film layer to form a separate TCO substrate;
- Laser etching of other film layers above the TCO to provide the positive and negative electrodes of the two neighboring sub-cells to provide transmission channels;
- After depositing the back electrode, laser etching of other film layers above TCO separates the sub-cells from each other;
- Remove the deposited film at the edge of the cell to prevent leakage and ensure the reliability of the battery package.
Each subcell contains two regions: the dead zone and the active zone. The outermost area of the first 3 processes cannot generate power, commonly known as the dead zone. The greater the width of the dead zone, the greater the proportion of ineffective power generation in the battery, the lower the efficiency of the sub-cell, therefore, the laser scribing process of titanium dioxide photovoltaic cells, one of the core technical indicators is to minimize the dead zone. In addition to the product's own design line width has an impact on the dead zone width, the line and line spacing should be as small as possible, the middle can not be intersected or parallel lines, so the smaller the spacing, the higher the control accuracy of the equipment processing system requirements.
In addition to the dead zone control, the laser process effect also affects the photoelectric performance of the battery to a large extent, the laser etching depth requirements are strict, need to control the laser energy and frequency, the goal is to remove the film layer on the basis of clean to achieve no crater and thermal effects, line uniformity. In addition, how to deal with the dust generated by laser scribing to prevent contamination of the film layer is also a key point.
Applied to laboratory research / R & D level thin film battery product development in the early stages of small format thin film battery product validation, the laboratory cm2 level of micro-cells cell expansion into a small thin film module with sub-cells in series structure (300mm × 300mm), through the scribing equipment can be verified to prepare thin film module technology transplanted to the feasibility of large-scale mass production line. This equipment is compatible with the film surface and glass surface out of the laser scribing and edge clearing, can be customized according to the customer's actual product size of different processing platforms; the use of scientific research-grade marble structure, high-speed linear motor movement platform, to ensure the stability of the system, the processing accuracy and efficiency; according to the customer's spectral absorption characteristics of the film layer material to select different wavelengths of the laser light source, dedicated to the low caldera, no thermal impact and other high-quality processing results! It is the first choice of laser equipment for experimental and small pilot line in chalcogenide industry.
Applied to the mid-stage of calcite product development, pilot line before large-scale mass production; large-area preparation is a prerequisite for commercialization, while the enlarged area will greatly increase the difficulty of film preparation, scribing uniformity and precision assurance, and is very prone to uneven preparation, instability and other problems, reducing the conversion efficiency. High-precision etching of different film layers on a large-area substrate to produce high-performance battery components is a challenging challenge to overcome.
Core advantages of the equipment
Structure:
- Special buffer to realize high-speed operation. The whole machine anti-vibration design, module rigidity design, committed to optical vibration isolation, system stability;
- Flying optical path laser processing process product static;
- Each optical path focus, pitch automatic adjustment, precision ± 1μm.
Optics:
- The use of mechanical beam-splitting method to achieve 8-12-way beam-splitting, parallel processing to improve processing efficiency;
- Structure lightweight design can meet the GW line more than 2.5m/s, 3g processing speed load requirements;
- The power of the optical path is independently adjustable, and the modular optical path design realizes the processing of film surface or glass surface;
- Mechanical spectroscopy of the optical design of the optical path power consistency of less than 3%, for the film surface processing of the optical path power consistency is high, to a greater extent to improve the film surface material process window is small, the power consistency of the high requirements of the processing effect.
Software:
- Self-developed software, simple and clear interface, complete functions, easy to operate;
- With height tracking, trajectory tracking, power detection, dead zone monitoring and other functions.
