Equipment and process for preparing back passivation solar cell

Abstract

The invention discloses equipment and a process for preparing a back passivation solar cell. The equipment and the process for preparing the back passivation solar cell comprise a feeding cavity, a first process cavity, an isolation cavity, a second process cavity and a discharging cavity, valves are arranged among cavity bodies of the feeding cavity, the first process cavity, the isolation cavity, the second process cavity and the discharging cavity; heating plates are laid in the first process cavity and the second process cavity, a transmission roller is arranged in each cavity which is connected in sequence, a tray loaded with a silicon wafer is transmitted on the rollers, and the tray loaded with the silicon wafer passes through the feeding cavity, the first process cavity, the isolation cavity, the second process cavity and the discharging cavity in sequence. Through the mode, a tunneling silicon dioxide film layer and a doped amorphous / microcrystalline silicon film layer of the Topcon solar cell are prepared at the same time, the Topcon solar cell with higher efficiency can be prepared, ion damage is avoided, dynamic transmission is achieved, the uniformity of the film layers is improved, and the productivity is improved.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a device for preparing a back passivated solar cell and a process thereof. Background technique [0002] The large-scale use of traditional fossil energy has caused serious damage to the environment, and is gradually facing the problem of exhaustion. Therefore, the use of new energy such as solar energy has become an important choice for human development. With the gradual realization of grid parity, the solar cell industry It has developed rapidly in recent years. At present, PERC solar cells occupy most of the solar cell market due to its high conversion efficiency and low manufacturing cost, but the improvement of its conversion efficiency has almost reached the bottleneck period, and the cost reduction space is relatively narrow. Considered to be the next-generation solar cell technology route with higher conversion efficiency, Topcon solar cells can increase the conversi...

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Problems solved by technology

[0002] The large-scale use of traditional fossil energy has caused serious damage to the environment, and is gradually facing the problem of exhaustion. Therefore, the use of new energy such as solar energy has become an important choice for human development. With the gradual realization of grid parity, the solar cell industry It has developed rapidly in recent years. At present, PERC solar cells occupy most of the solar cell market due to its high conversion efficiency and low manufacturing cost, but the improvement of its conversion efficiency has almost reached the bottleneck period, and the cost reduction space is relatively narrow. Considered to be the next generation solar cell technology route with higher conversion efficiency, Topcon solar cells can increase the conversion efficiency of industrialized solar cells by about 1-1.5%

[0003] At present, the equipment used to prepare tunneling silicon dioxide films and doped amorphous / microcrystalline silicon films for Topcon solar cells are generally low-pressure chemical vapor deposition coating LPCVD equipment (hereinafter referred to as LPCVD equipment), static plate plasma enhanced chemical Vapor deposition coating PECVD equipment (hereinafter referred to as PECVD equipment) or tubular PECVD coating equipment, the use of LPCVD equipment requires a very high process temperature, generally 500-900 ° C, which is easy to cause damage to the silicon wafer itself, and the high process temperature also increases equipment. Life loss, increased power consumption, and LPCVD coating rate is very slow, equipment production capacity is low, there are also very serious winding plating problems, and it is not easy to achieve online in-situ doping

[0004] Using static plate PECVD coating equipment to prepare the tunneling silicon dioxide layer and doped amorphous / microcrystalline silicon film layer of Topcon solar cells can improve the winding problem, increase the coating rate, and reduce the reaction temperature. The reaction temperature can be controlled within the range of 200-500°C, but it is difficult to control the uniformity of the film layer by using static plate PECVD equipment to prepare the ultra-thin silicon dioxide film layer, and the coating rate is fast, the film quality is not excellent enough, and The plasma coating process is accompanied by ion damage, which affects the passivation performance of silicon dioxide. When using static plate PECVD equipment to prepare doped amorphous / microcrystalline silicon thin films, due to the thick film layer, the film layer is 100-200nm , a larger coating chamber is required to increase production capacity, and the area of ​​the spray plate is also increased. When the temperature of the heating plate is higher than 250°C, the spray plate is prone to deformation after being radiated by the heating plate, which seriously affects the uniformity of the coating , and when the static plate PECVD equipment is used for coating, the plasma needs to be turned off when each tray enters and exits the coating chamber, and the chamber is pumped to the lowest pressure, and the tray needs a heating after entering the chamber The process of stabilizing and introducing the process gas to stabilize the pressure, and then turning on the plasma for coating, these actions waste the coating utilization time of the process chamber and reduce the production capacity

[0005] When using tubular PECVD equipment to prepare doped amorphous / microcrystalline silicon films, since the ceramic rods and ceramic collars connected between the graphite boats are easy to be plated with doped amorphous / microcrystalline silicon film layers, the doped The electrical conductivity of the final amorphous / microcrystalline silicon film layer is very high, which leads to the conduction between the positive and negative electrodes of the graphite boat, and the coating cannot be continued, so that the function of online doping cannot be realized. In addition, tubular PECVD equipment generally uses relatively low frequency Low power supply, generally 40KHz-250kHz, when coating with low frequency power supply, it is easy to produce heavy ion damage, which reduces the passivation effect of the film layer

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