The first development of weaving structure flexible solar cell

Korea Electrotechnology Research Institute (Dong-yoon Lee, Principal Researcher)

Korea Electrotechnology Research Institute (KERI) established in 1976 under the name of Electric Device Test Research Center is a government-funded research center specialized for electricity governed by the National Science & Technology Research Society in the Ministry of Science, ICT and Future Planning. Taking the first ranking for research productivity among government-funded science and engineering research center, and the
second ranking for research performance technical transfer to realize creative economics, it is a representative funded research institute in electricity, science, and technology fields. KERI developed technology for the first time in the world to weave solar cell like weaving fabric on a loom that can generate electricity modeled after photosynthesis.

The first fabric solar cell, utilizable in various areas including wearable devices

Recently, wearable devices are taking center stage as a nextgeneration core technology and business including Google’s ‘Google glass’ and Fitbit’s ‘Health care smart band’, Samsung,
Sony, Qualcomm are making competition, presenting watch type and band type devices. The utilization range of wearable technology are expending not just to wearable devices including smart glasses, smart watch, smart bracelet, and smart shoes, but also for special purpose fields, such as military and firefighting, and even for life aid, health care, infotainment, human ability improvement, and so forth. Therefore, developing an effective power source to supply power to these wearable devices is also getting attention. It is essential that the power for wearable devices needs to be flexible, light, and highly impact resistant. There is no solar cell having such features in the market other than the one using amorphous silicon. But this solar cell cannot be used commonly either except some special military purposes, because it is vulnerable to bending or moisture.


Alternatively, fabric style solar cell development is attempted competitively in advanced countries. But, producing actual fabric in former method is practically impossible, because tension (pulling force) and friction which happen inevitably in the weaving process were not considered. On this occasion, KERI produced the electrodes of solar cell with weaving process and applied screen printing process to manufacture solar cell using a loom, through this research task. Developing fabric weaving style solar cell, practically wearable solar cell that can be used in various environments, is the first time in the world. The developed solar cell is so flexible to fold and the first fabric solar cell with high durability, it receives a lot of attention from global outdoor, leisure, smart home, and mobile electronic device manufacturers. Hence early commercialization, if a success, would create new global markets in these fields.

Contributing to enhancement of IT-based life convenience

Centralized weaving dye-sensitized solar cell developed in this research is fabric style solar cell made by weaving electrode (anode and cathode) structure in solar cell with a loom using metal and ceramic fiber like weaving fabric, and printing optical electrode and dye in the screen printing process. Metal weaving technology, a core technology of solar cell, has not been developed in any other country over the world, and this core technology produces high density metal fabric electrode using metal fiber only. To do this, the development team developed a new loom independently and successfully produced various fabric patterns suitable for solar cell. Also, the team developed technology mixing metal fiber, ceramic fiber, and natural fiber to create various types of solar cell. The developed fabric weaving dye-sensitized solar cell is basically composed of three layers: optical electrode, electrolyte, and counter electrode. To produce such 3-layer conformation solar cell, the team developed 3D weaving technology that can weave metal fiber and ceramic fiber in 3-layer at one time.
In this context, Dong-yoon Lee, senior researcher in KERI and general manager of this research task said about the hardest difficulty in the technical development was “Because we tried fabric solar cell development for the first time in the world, we could not find useful equipment or material from existing technologies, but had to develop all of them by ourselves.


Especially for metal fabric loom, we designed and made it with new weaving algorism because of unusual weaving patterns, which involved a lot of time and costs.”
Fabric solar cell developed by overcoming such difficulties is flexible and soft like a textile and can be cut or sewn. Also, many kinds of pattern are available depending on usage environment and application subject. Especially, you can make solar cell in various forms: sew electrode (attaching type) made from the weaving process on existing fabric, such as cotton, silk, and pelt; insert electrode (fabric inserting type) when you make a cloth; or weave them all (weaving type), therefore its application scope and possibility are rated as high. Currently the performance of fabric weaving type solar cell shows 6% of efficiency, 0.4cm of bending radius (solar cell is working even the fabric is folded), and can maintain 80% or more efficiency even after 2000 or more 90 degree bending tests.
Such technology is expected to greatly contribute to enhancing IT-based life convenience. It can be applied to wearable devices, such as Samsung’s Gear and Fitbit’s Smart band; battery-free tent or backpack to be used in camping, the most popular leisure activity; built-in solar cell in building and curtain at home. Potential for military application is also high. Applying weaving type flexible solar cell technology to military barracks, combat backpacks and military caps allows us to generate and use electricity in the military field.

After core technical development, move to its commercialization

Fabric weaving solar cell can be utilized in various areas including wearable devices, military, leisure, health care, and household (blinder). In order to industrialize this main technology, KERI introduces the technology through domestic and foreign symposiums and conferences, and also maintains close mutual cooperation with Gyeongsangnam-do Province. In this context, Dong-yoon Lee senior researcher in KERI who started the research to develop a structure having outstanding durability and superior flexibility in flexible solar cell and flexible cell fields, forecasted that “Currently, with given core technology we developed, it may take about 3 years for relevant commercialization depending on the application area.”

Now, in the commercialization consortium that received the technology from KERI, development is on going targeting for the 1st products including smart home solar cell blinder, smart band solar cell, smartphone charging solar cell, and health care solar cell. Because some products get attention from many global companies, no big trouble is expected to form a market for commercialized products Although prediction for the market is difficult because no product was developed for sale yet, minimum 100 billion won of sales are estimated per year because these products are independent without any rival. And trillions of global market would be available if application of wearable devices is
Seng-il Cha, senior researcher in KERI who participated in this research task said that “It is the world’s first development for solar cell that properly utilized weaving structure. Although there are tasks to be solved before commercialization, such as sealing technique, electrolyte technique, and efficiency optimization, but because we succeeded the very core weaving solar cell structure development, remained technical issues can be associated with application scope and developed accordingly” and “First of all, application for military and leisure seems to possible, and further application in various fields would be possible, as the wearable market is being formed in full-scale and requests for built-in solar cell. increasing.”

2016-03-14 11;38;26.PNG | Blog Magazine of korean electronics, brands and Goods

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