On June 22, China Green Development Investment Group announced that its subsidiary, Beijing Green Development Zhongke Lithium Capacitor Technology Co., Ltd. (hereinafter referred to as China Green Development Lithium Capacitor Company), has successfully completed a full set of type tests for its independently developed and manufactured 5MW all-carbon supercapacitor power module. The module has obtained a certification report from the China National Accreditation Service for Conformity Assessment (CNAS), which is internationally recognized. This marks the first 5MW all-carbon supercapacitor power storage device in China and globally to pass the CNAS-certified type test as a complete module.
As the construction of new power systems accelerates, energy storage devices are playing an increasingly important role in grid frequency regulation. Traditional lithium battery energy storage devices store a higher total amount of electricity but have a cycle life of only a few thousand cycles, making them unsuitable for high-frequency charging and discharging. In contrast, supercapacitors, while storing less total electricity than lithium battery storage devices, offer extremely high power density, enabling millisecond-level response to grid frequency regulation commands. They also have an exceptionally long cycle life, making them ideal for frequent and high-intensity frequency regulation scenarios. Therefore, supercapacitors are suitable for combined use with traditional lithium battery energy storage devices.
"Compared to common hybrid supercapacitors and electric double-layer capacitors on the market, all-carbon lithium-ion supercapacitors offer advantages such as longer cycle life, higher safety, lower attenuation at low temperatures, and no risk of lithium dendrite combustion," said Li Ming, Chairman of China Green Development Lithium Capacitor Company.
Li Ming explained that this supercapacitor power module is equipped with 4500-farad large-capacity all-carbon lithium-ion supercapacitor cells produced by China Green Development Lithium Capacitor Company. The supercapacitor cells utilize pre-lithiation technology and a porous electrode structure design, achieving an energy density of 16 watt-hours per kilogram (Wh/kg) and a power density of 18 kilowatts per kilogram (kW/kg). The power module employs an active balancing strategy, enabling real-time scheduling of 22,400 supercapacitor cells, with a cluster-level dynamic voltage difference of only 64 millivolts, conversion efficiency exceeding 95%, instantaneous power response speed within 10 milliseconds, and a cycle life of over one million cycles for the entire module, suitable for daily high-frequency charging and discharging conditions of hundreds of cycles.
"Moreover, this device can continuously and stably output 5MW of power under extreme conditions at an altitude of 5,000 meters, making it one of the few megawatt-class supercapacitor equipment in China capable of covering wind and solar energy storage projects across the Qinghai-Tibet Plateau," Li Ming added.
The 5MW all-carbon lithium-ion supercapacitor power module that passed the type test will be deployed in the Qinghai Dongyue independent energy storage project. It will bring millisecond-level rapid response to the energy storage station, achieve over one million ultra-long cycles, require no cell replacement throughout its entire lifecycle, and adapt to the plateau's extreme cold environment without the need for additional temperature control or pressurization equipment. This will significantly reduce station supporting investment and enhance the frequency regulation revenue of the power station.