Smart Energy Systems Power Drones

At the foot of Mount Huangshan in Anhui province, an industrial drone glides over the green leaves in a tea garden. It doesn't need to frequently return for charging, and on a single flight can complete the monitoring and early warning of pests and diseases across the entire garden.

The drone is powered by a high specific energy hydrogen-lithium hybrid power system independently developed by a team led by Chen Zhongwei, a researcher at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences. It provides energy solutions that adapt to extreme environments, and has ultra-long flight times and high flexibility for low-altitude aircraft, which will promote the technological upgrading and application of China's low-altitude industry.

Improving the battery capacity

Traditional lithium battery-powered drones generally have a battery life of only 30 to 60 minutes and their load-carrying capacity is limited. Their performance significantly declines in complex environments such as mountainous areas, high temperatures, and extreme coldness. Chen's team has targeted the demand for energy systems in low-altitude aircraft and developed two core technologies.

The technologies, namely high specific energy ultra-low temperature battery and high specific energy hydrogen-lithium hybrid technology, have conquered the problems of short endurance and small load capacity of industrial drones.

In the extremely cold test at -36°C in Mohe, Heilongjiang province, high specific energy ultra-low temperature lithium batteries can power six-rotor drones to complete stable flight and cargo transportation tasks, Zhang Meng, the team's person in charge of power supply technology, told Science and Technology Daily.

The battery's operating temperature range is from -40°C to 50°C. It can maintain a discharge capacity of over 80 percent at -40°C and can still be charged at -20°C. With a stable power output, it has even served polar scientific expeditions.

"We equipped the drone with a dual-engine," said Chen, explaining that his intelligent system dynamically coordinates lithium batteries and hydrogen fuel cells, which not only makes up for the slow dynamic response of hydrogen fuel but also avoids deep discharge of lithium batteries.

High-efficiency operation

The core of this "dual-engine" system lies in the precise scheduling of the intelligent energy management system.

Zhang explained: "Just like the hybrid mode of a car, when kicking off, the lithium battery instantly releases high power (with a peak power up to 20 kilowatts), while the hydrogen fuel cell supplies power during the cruise phase (with a power of about 5 kilowatts) and also replenishes the lithium battery."

This coordination keeps the system always operating efficiently, reducing energy consumption by 18 percent compared to a single energy solution.

To improve the adaption of traditional hydrogen fuel cells, the team has innovated the design of materials and controlling pattern, said Wu Si, the technical person in charge of the team's intelligent management system.

They adopted an eight-micron ultra-thin proton exchange membrane and an independently developed composite catalyst and hydrophilic group modification technology system to equip the membrane electrode with a self-humidification function. The cathode diffusion layer is designed with a gradient pore size structure to optimize the gas flow distribution and prevent water flooding or membrane drying.

The dynamic control system can predict and adjust the air flow, ensuring the stability of the drones during intense flight. High specific surface area heat dissipation fins and mass transfer enhancement technology improve heat dissipation efficiency and optimize reaction efficiency, ensuring the efficient and stable operation of the battery.

In addition, the team has also solved the problem of ultra-low temperature performance degradation of lithium batteries through the "anti-freezing formula" of the electrolyte and the modification of the negative electrode material.

Full-chain ecosystem

The ultimate value of technological breakthroughs lies in promoting the deep integration of innovation and industry.

According to Zhang, through multiple testing flights, the team has established a battery database under multiple scenarios, environments and dynamic loads, providing references for all-weather, wide-range temperatures and cross-regional flights, and improving the maturity of the technology.

At present, the hydrogen-lithium hybrid power technology has completed pilot production and approval, and has entered a period of accelerated commercialization.

Equipped with the hybrid power system, drones can be used in multiple fields such as agriculture, culture and tourism, forestry, fishery, and emergency response, to monitor natural resources and issue early warnings for diseases.

"We are building a full-chain ecosystem covering materials, components, systems and scenarios," said Chen. Shanghai Emperor of Cleaning Hi-Tech Co., Ltd has established a branch dedicated to producing hydrogen-hybrid power cells and high specific energy lithium batteries. Its production line is under construction, with a planned annual production capacity of 7,500 sets of power systems.

Chen stated that the team will continue to delve deeply into hydrogen-lithium coupling technology, making China's energy solution a green benchmark for the global low-altitude economy.

Source: Science and Technology Daily