Busbar-free high-efficiency back-contact solar cell, module and its preparation process

Abstract

The invention relates to the field of solar cells, in particular to high-efficiency back-contact solar cells without busbars, components and a preparation process thereof. A busbar-free high-efficiency back-contact solar cell, the solar cell includes a solar cell sheet and an electrical connection layer, and the backlight surface of the solar cell sheet has a P electrode connected to the P-type doped layer and an N electrode connected to the N-type doped layer. The electrode is characterized in that: the electrical connection layer includes several conductive thin grid lines, a part of the conductive thin grid lines are connected to the P electrode on the backlight surface of the solar cell sheet; the other part of the conductive thin grid lines is connected to the solar cell The N electrode on the backlight surface of the cell is connected, and the conductive thin grid line is a multi-segment structure. The beneficial effect is that the amount of silver paste is reduced and the cost is reduced. The arrangement of multi-segment conductive thin grid lines reduces the series resistance and the transmission distance of the fill factor, improves efficiency, and can effectively reduce the impact of conductive thin grid lines on the battery sheet. stress.

Description

technical field [0001] The invention relates to the field of solar cells, in particular to high-efficiency back-contact solar cells without busbars, components and a preparation process thereof. Background technique [0002] Energy is the material basis of human activities. With the continuous development and progress of human society, the demand for energy is increasing day by day. Traditional fossil energy is non-renewable energy and it is difficult to continue to meet the needs of social development. Therefore, research and utilization of new energy and renewable sources have become increasingly popular in countries around the world in recent years. Among them, solar power generation technology has the advantages of directly converting sunlight into electricity, simple use, environmental protection and pollution-free, high energy utilization rate, etc., and has received widespread attention. Solar power generation uses large-area P-N junction diodes to generate photo-gen...

AI Technical Summary

Problems solved by technology

This process has the following defects: 1. The composite conductive backplane used is a composite conductive metal foil in the backplane, usually copper foil, and the copper foil needs to be laser etched or chemically etched

Since laser etching is still operable for simple patterns, the etching speed is slow and the production efficiency is low for complex patterns, while chemical etching requires pre-prepared complex-shaped and corrosion-resistant masks, environmental pollution and corrosive liquids on polymers. Substrate corrosion problems

Therefore, the manufacturing process of the conductive backplane manufactured in this way is complicated and the cost is extremely high.

2. It is necessary to punch the packaging material of the back layer of the solar cell so that the conductive adhesive can penetrate the packaging material. Since the packaging material is usually a viscoelastic body, it is extremely difficult to accurately punch holes

3. Accurate dispensing equipment is required to coat the conductive glue on the corresponding position of the back plate. It can also be operated for batteries with fewer back contacts such as MWT, and for back contact batteries with small and large number of back contacts such as IBC. Simply not possible with dispensing equipment

[0012] To sum up, using thin grid lines for current collection will encounter problems such as increased series resistance and decreased fill factor, resulting in a serious reduction in the power of the manufactured components; screen printing wider silver paste grid lines to reduce series resistance , but the cost will rise sharply due to the increase in the amount of silver used, and at the same time, the wide gate line will also cause the insulation effect between P-N to deteriorate, and the problem of easy leakage

If metal conductive wires are used to collect the conductive particles of the back-contact solar cells, since the thickness of ordinary solar cells is only 180 microns, in order to accurately position, when welding metal conductive wires, it is generally necessary to apply a tension before welding. Will be subject to the longitudinal stress of the conductive wire, easy to bend

And if the entire string of solar cells is strung together using the same conductive wire, it will increase the difficulty of series connection and the probability of "wrong connection", and hinder the thin development of solar cells (the theoretical thickness of solar cells is 45 microns can)

Images