KEPCO and VINATech joint-developed Graphene SuperCapacitors

2020-02-07 [09:09]
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KEPCO's 1st graphene ESS Developer Investment profit expected over 200%

Korea Electric Power Corporation(KEPCO) developed ‘1100V graphene supercapacitor ESS' in collaboration with  VINATech, Korea Institute of Science and Technology(KIST), Gachon University. This product is an 1100 volt energy storage device using graphene, which is called 'Dream material', in supercapacitors. KEPCO unveiled prototypes in Oct 2019. Atinum Investment invested 357k shares of VINATech since 2017 and the valuation gain is expected to increase 200% as VINATech’s corporate value has increased.

 KEPCO's graphene ESS has applied advanced technology compared to the existing ESS in terms of energy density, lifespan, and safety. In addition to adjustment frequency and renewable energy connection, it can be used for electric vehicles, electronic products, smart buildings, and IoT that require high output performance. If commercialization of the graphene ESS is achieved in 2022, VINATech’s earnings and corporate value will also increase.
 VINATech is a company that specializes in developing energy storage devices such as SuperCapacitors. Ultracapacitors have a smaller charging capacity than ordinary rechargeable batteries but have high instantaneous output. It is mainly used for special application fields of electrostatic protection devices and smart meters and smart grids, therefore, the demand for ultracapacitors is expanding. (Source:etoday.co.kr, Oct 2019) 

ESS Future Solution for Renewable Energy Technology

KEPCO focuses on developing renewable energy technologies while energy source diversification becomes the global mission. Therefore it is actively engaged in commercialization and overseas export of new technologies developed from R&D. This time introduces ESS solution.
The capacitor charges when the voltage is high and release charge when the voltage is low, similar to a battery, storing and exporting electricity. But capacitors have different principles. Li-Ion Battery based on a chemical reaction that generates current as Lithium-Ion moves. But Capacitors store energy by generating an electric field from dropping positive and negative charges. The capacitance is one-tenth of battery but the power density is 100 times higher. High power density can quickly charge and discharge therefore Capacitors are applied to appliances, robot, industrial equipment, and electric vehicles.

For renewable energy system, SuperCapacitors to solve Voltage Instability

Supercapacitors, which increased the capacitor’s capacitance up to several thousand times, became commercially available from 1955 in Japan, Russia and the United States and more fields are applying SuperCapacitors. KEPCO has developed the Graphene SuperCapacitors to quickly solve the voltage instability generated in the power system. To prevent global warming, as the proportion of fossil fuel power generation decreases, power generation using renewable energy is expanding worldwide. However, the typical renewable energy, solar and wind power generation has a problem that the output greatly changes depending on the weather. 
Frequency fluctuations in the power system require Frequency adjustment.

Such output fluctuations lead to frequency fluctuations in the power system and thus deteriorate the quality of the power and thus require adjustment frequency. KEPCO installs and operates an energy storage device using lithium batteries in 13 substations for adjustment frequency and is conducting various studies for stable power supply. However, the Li-Ion battery constituting the energy storage device has a disadvantage in that it is difficult to cope with frequent charging and discharging with a lifespan of about 5000 to 6000 times during full charging and discharging. Besides, when responding to a sudden frequency fluctuation, there is a disadvantage in that the power density is low, which makes it difficult to respond to rapid charging and discharging, and a lifespan problem occurs such that the capacity gradually decreases due to frequent charging and discharging.

Supercapacitors are getting attention as it can overcome the shortcomings of lithium-ion batteries and extend their lifespan due to their long life, safety and high output characteristics. Currently, commercially available supercapacitors have limited energy storage densities, which limit their application. Electrode materials are also activated carbon and mostly depend on Japan's imports.

Graphene is a type of carbon complex that consists of carbon atoms. In 2010, Professor Andre Gaim won the Nobel Prize for stripping graphene from graphite with adhesive tape. Graphene is called dream material because of excellent electromigration and low resistance compared to others. The electrical conductivity is over 100 times better than copper, and heat transfers better than diamond, which has the highest thermal conductivity of any material. And it's 200 times harder than steel, but it's so elastic that it doesn't break when you bend it. When graphene is used as the electrode of supercapacitor, the surface area is increased by about 2 times and the power storage capacity is increased by 6 times than that of the activated carbon supercapacitor. 

In 2018, KEPCO succeeded in producing large-area graphene electrodes, developed for the first time globally. In 2019, a cylindrical supercapacitor improved the capacitance performance to 4500F. Compared to the ctivated carbon, the maximum power density is 8000W/kg and the energy density is over 5 times higher. KEPCO developed 60V 220F Modul, 20 modules in series, to complete 1100V Graphene Supercapacitor ESS Prototype.

Passed safety tests such as internal short circuit, shock, and overcharging from internationally recognized test institutes.

KEPCO’s graphene supercapacitor passed safety tests such as internal short circuit, shock, and overcharging from internationally recognized test institutes. In Dec 2019, the system was installed and commissioned with a maximum output of 100kW, 100C-rate (charge/discharge in 36 sec.) and high-speed charging and discharging.  Finally, in 2022, KEPCO plans to complete commercialization products that are stable to the system in terms of lifetime cost by optimizing lithium-ion batteries and parallel operation systems, increasing operational stability, developing control strategies considering algorithms, and optimizing algorithms.

Development of the full-cycle graphene supercapacitor in-house will secure high-output renewable ESS stability and will be used to resolve excessive output fluctuations in renewable energy. Also, by replacing graphene supercapacitor for FR ESS with Li-ion battery, the life expectancy of the whole ESS can improve over 1.5 times. Also, through various distributed power supply system stabilization technology development, it will lead the global renewable market in the early stage.
High capacitance graphene supercapacitors demands will rapidly increase in the future as the improvement of power supply reliability of renewable energy, elimination of output instability, and the necessity of new power storage from the microgrid and DC power distribution application according to international environmental friendly policies and the introduction and operation of smart grid. Even electric vehicles such as hydrogen fuel cell electric vehicles, and ESS auxiliary power sources and general industrial devices may take SuperCapacitors into considerations for key components. (Source: Energynews.co.kr, Jan 2020)
VINATech has provided technical service of Supercapacitors to KEPCO until Jan 15, 2020.

VINATech, established in 1999, has developed and produced SuperCapacitor and Fuel Cell Membrane Electrode Assembly, and is equipped with smart factory-based production facilities with the highest level of automation in order to ensure the highest quality level. For more information, please call +82 31 448 3066 or email hycap@vina.co.kr for supercapacitor and fuelcell@vina.co.kr for fuel cell components, also you can check the web site.
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