太阳电池超细栅电极喷印控制系统设计与实现

针对传统丝网印刷技术制造太阳电池金属化栅极容易造成基材破损，且制造的栅极精度和高宽比很难提高的问题，采用喷墨技术直接将纳米银墨水打印到太阳电池基材上实现栅极金属化，并设计实现了太阳电池栅极喷印样机系统．样机系统通过USB模块实现高速数据通信；两组动态随机存储器（SDRAM）内存模块构成乒乓操作，实现不间断打印；喷印控制模块采用现场可编程门阵列（FPGA）产生喷头复杂时序波形和压电驱动波形．基于流体体积法建立了微液滴喷射模型，研究了微滴喷射机制及压电驱动波形幅值对微液滴尺寸、速度一致性的影响，并进行实验验证．通过优化喷印分辨率和在线固化温度进行系统测试，结果表明，多晶硅硅片固化温度80 ℃条件下，随着喷印层数的增加，栅极高度线性增加，喷印一层大约增高0.5 μm，栅极宽度基本维持在35～40 μm，打印层数60～80层时，形成三维形貌均匀的具有高“高宽比”的栅极．

Design and Implementation of Ink-jet Printed Fine Line Metallization System for Crystalline Silicon Solar Cells

The use of traditional screen printing technology leads to the breakage of silicon substrates. Moreover, such traditional technology is unable to efficiently improve the precision and aspect ration of the fine line mettalization. Based on these issues, ink-jet printing technology is proposed in this study to fabricate the fine line front side metallization, which can directly eject the nano-silver ink onto the silicon substrate. Meanwhile, the ink-jet printed fine line metallization prototype system for crystalline silicon solar cells is designed and implemented. The proposed system, which can fabricate fine lines by one time ink-jet printing, includes a USB high-speed communication module that achieves high-speed communicaiton, and SDRAM memory modules to carry out ping-pong operation to achieve continuous printing. Nozzle complex timing waveforms and drive voltage waveforms, which are generated by field programmable gata array (FPGA) control module drive piezoelectric ceramics, are used to generate uniform droplet streams. The numerical model based on the volume of fluid is established to gain a deeper understanding of the droplet spraying process. The influence between the driving voltage amplitude and droplet size and droplet velocity is also studied and experimentally verified. Experimental results show that when the polycrystalline silicon substrate temperature is under a curing temperature of 80 ℃, the height of the multi-layer fine line increases linearly, with line thickness 0.5 μm for a single pass. Meanwhile, the width of the print line remains at a range of 35 μm~40 μm. When the layers increase to 60 μm~80 μm, the three-dimensional uniform fine line with high aspect ratio topography is achieved.