Chinese PV manufacturer, Zhongli Talesun, has said the filing of a patent infringement case by Kyocera Corporation against the Japanese subsidiary of Hanwha Q CELLS on the use of a ‘three-busbar electrode structure’ was a “crisis signal to most PV manufacturers”.

Kyocera filed a lawsuit with Tokyo District Court last week over the alleged breach of patent 4953562 issued in Japan in March 2012 covering its three-busbar designed solar cell.

According to Zhongli Talesun, the 4953562 patent was widely known about and was issued near the beginning of the boom in PV installations in Japan. As a result of the patent being issued, Zhongli Talesun said that it had the potential to lead to patent law cases as the three busbar cell structure was widely used by PV manufacturers.

The company therefore said that as a direct result it had allocated R&D resources to develop, patent and commercialise a four-busbar design, negating any patent infringement issues with the Kyocera patent.

“We have independent intellectual property rights, so it’s free from Kyocera’s ‘three-busbar electrode structure’ patent blockade,” said Dr. Ni Zhichun, vice president of R&D department at Zhongli Talesun. “The ‘four-busbar’ design makes transmission path of electric current more reasonable, it also reduces cells' series resistance, and decrease busbar breaking.

"Four-busbar electrode structure is combined with anti-breaking finger electrode structure; this design is beneficial for cell to collect more light current, cell efficiency improved more than 0.2%, module power improved more than 0.6%”. Compared with the normal three-busbar module, Zhongli Talesun’s four-busbar module is more efficient and stable.”

Zhongli Talesun noted that it had already started large volume shipments of modules using its own four-busbar design to customers in Japan, US and Europe since 2013.

“Due to the high subsidies, the Japanese PV market has become one of the world’s hottest markets since July 2012. The Chinese manufacturers have also expanded rapidly in Japan, with market share increased to 50% within only six months after July 2012. However, most Chinese PV modules are based on ‘the three-busbar electrode structure’,” said Frank Qi, vice president of sales and marketing, Zhongli Talesun. “The well-known Japanese enterprise proposed the patent war of ‘three-busbar electrode structure’ at this time; it’s a crisis signal to most PV manufacturers. While with independent intellectual property rights, Zhongli Talesun has already got the patent for four-busbar solar cell both in China and Japan.”

Hanwha Q CELLS has told PV Tech that it was aware of Kyocera’s issued statement over starting legal proceedings against its Japanese subsidiary but had not yet received a copy of the petition.

The company said in a statement to PV Tech that it would refrain from making comments on the petition until it was received and fully reviewed.�