Solar cell R&D stays focused on thin-film technology

Midsize and large companies in China pursue nonsilicon-based solar cells, with some in the latter group already into mass manufacture.

Improvements in thin-film technology are catching up with solid gains achieved in traditional but still-dominant silicon-based solar cells, encouraging tiers 1 and 2 China makers to keep the former a product development priority.

Local efforts will revolve around the use of III-V and II-V semiconductor materials such as cadmium telluride or CdTe, copper indium gallium diselenide or CIS/CIGS and gallium arsenide or GaAs. This is to realize thinner units, which are typically less than 10µm and have a conversion efficiency of 13 percent.

A recent breakthrough was made by Alta, a US-based company now a subsidiary of China's largest thin-film solar cell manufacturer Hanergy, based on GaAs. Such solar cells have reached up to 29.1 percent, exceeding the world efficiency record of 28.9 percent realized in early 2018. These are already being produced in high volume.

Hanergy has set up several manufacturing bases for the thin-film category in different provinces, including Sichuan, Guangdong, Zhejiang, Jiangsu, Shandong and Hainan, with 3GW total annual capacity. In addition to Alta, it acquired Germany-based Solibro and two other US companies, Miasole and Global Solar.

Only major companies are turning out thin-film types due to the high technology and the limited availability of required materials. Besides Hanergy, there are Fenghan, the Zongyi Group and the Tongwei Group. The last started production in large quantities in its new facilities in Hefei and Chendu in Anhui and Sichuan provinces in 4Q2018.

In the mainstream silicon-based category, there are initiatives to reduce thickness to between 80 and 100µm by 2020. Current releases are 180 to 280µm-thick.

All such undertakings bank on the market's steady growth, which is also the reason the majority of China suppliers will continue to increase their output until 2020.

Zhejiang Isola New Energy Co. Ltd, which bolstered production by 20 percent in 2018, has allocated nearly $1.5 million for the acquisition of new equipment to maintain this rate of expansion through 2020. It sends 90 percent of turnout to Europe and the US, and projects exports will rise by 10 to 15 percent.

China is the largest manufacturing base for solar cells, accounting for more than 60 percent of the volume worldwide. It will remain so amid sustained growth in output, which will settle within a 10 percent increase after seeing rapid development in the past five years. The hub is expected to hit 92GW in 2022, posting an annual increase of 10 percent from 2018, while its capacity will reach as much as 100GW in the same year, according to Zhiyan Consulting.

The country's thin-film category, however, represents a small portion globally at present.

There are more than 300 makers of solar cells in China, of which more than 80 percent are local enterprises and the rest mostly US companies. The key local players include Yingli, Suntech, Hanergy, Trinasolar and JA. The first two are also among the top in the world.

Many offer solar panels, modules and systems as well. Solar cells represent between 20 and 80 percent of output of these suppliers.

Competition is intense so few new companies are expected to join the line in the next two years.

The main manufacturing bases are in the provinces of Jiangsu, Zhejiang and Jiangxi. About half of the makers are in the first, specifically in the cities of Suzhou, Wuxi and Changzhou. Some are in Baoding in Hebei province, Baotou in Inner Mongolia, and Shanghai.

Mono-, polycrystalline types

Thin-film solar cells will attract more maker attention, but at present, the silicon-based category dominates shipments with about 90 percent share.

In terms of production, polycrystalline units account for 70 percent, while monocrystalline counterparts have seen a rising share in recent years as suppliers strive to update the line. The latter is anticipated to represent half of the total in the next two or three years.

Typical models boast efficiency ranging from 10 to 20 percent. These have 18V and 6 to 8A operating voltage and current, and 120 to 150W maximum power.

Macsun Solar Energy Technology Co. Ltd offers a bifacial monocrytalline solar cell with up to 21.8 percent efficiency.

China makers source materials locally or from foreign providers, depending on customers' requirements.

Input cost has been flat and will remain so, keeping product prices stable. Due to competition, however, some companies might reduce their quotes to win more orders.

The products in this gallery have been handpicked by our China-based market analyst for representing current trends in solar cells and modules from China makers.

Monocrystalline solar cell with up to 21.8% efficiency

Macsun Solar Energy Technology Co. Ltd's model MS-B 5.304W-01 bifacial monocrystalline silicon solar cell has 21 to 21.8 percent efficiency, 0.556 to 0.567V maximum power voltage, 0.657 to 0.661A maximum current and 5.082 to 5.228W power. Its open-circuit voltage is 9.149 to 9.211V and short-circuit current 9.735 to 9.769A.

The minimum order quantity is 100 units. Delivery is within 15 days.

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200±20µm-thick polycrystalline solar cell

From Sopray Solar Group Co. Ltd, model SRSC156P156 polycrystalline solar cell has 4.186W maximum power and 17.2 percent efficiency. The 156x156mm unit has 200±20µm thickness.

An order of at least 100 units is required. Delivery takes 7 days.

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Monocrystalline solar cell has 20% efficiency

The LTS-18 model from Tianjin Lantian Solar Tech Co. Ltd is a monocrystalline solar cell with 20 percent efficiency. The 156.75x156.75mm unit operates in -40 to 85 C.

The negotiable minimum order is delivered within 7 days.

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350W solar module has 20.6% efficiency

This solar module from Zhejiang Isola New Energy Co. Ltd, YH350W-36M model, uses monocrystalline solar cells. It has maximum power voltage and current of 37.58V and 9.32A. The peak power is 350W. The unit with 20.6 percent efficiency has 45.09Vopen-circuit voltage and 9.88A short-circuit current. It operates in -40 to 85 C.

The 10-unit minimum order is for delivery within 10 days.

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