With the rapid development of the aviation industry, the power system of aircraft is becoming increasingly important, and the power lithium battery pack, as an important component of the aircraft power system, has many unique working characteristics, which are of great significance for improving the performance and safety of aircraft. Therefore, this article will introduce the working characteristics of aviation power lithium battery packs and their impact on aircraft performance and safety.
1 Working characteristics
(1)High energy density: Power lithium battery packs have high energy density, which can provide more energy, achieve longer range or higher power output.
(2)High charging efficiency: The power lithium battery pack has high charging efficiency, can complete charging in a short time, and has minimal energy loss during the charging process.
(3)Long lifespan: Power lithium battery packs have a long service life and can maintain high electrochemical performance in a large number of cyclic charge and discharge cycles.
(4)Fast charging and discharging rate: The power lithium battery pack can quickly complete charging and discharging, provide fast power response, and meet the dynamic performance requirements of aircraft.
(5)Temperature sensitivity: Power lithium battery packs are temperature sensitive, and both high and low temperatures can significantly affect their performance, requiring temperature management.
(6)High safety: Power lithium battery packs have high safety performance, avoiding the combustion and explosion phenomena of traditional battery packs.
2 Influence
(1)Improve the dynamic performance of aircraft: Power lithium battery packs can provide fast power response, which can better meet the dynamic performance requirements of aircraft.
(2)Improve the economic performance of aircraft: Power lithium battery packs can provide higher energy density and better charging efficiency, enabling longer range and lower fuel consumption.
(3)Improve the reliability of aircraft: Power lithium battery packs have a long service life and high safety performance, which can reduce the number of failures and repairs and improve the reliability of aircraft.
(4)Reduce aircraft emissions: Power lithium battery packs can reduce aircraft emissions and have a positive impact on environmental protection.
3 The impact of safety
(1)Temperature management of power lithium battery pack: Power lithium battery pack is sensitive to temperature and requires temperature management to avoid failure or malfunction caused by high or low temperature.
(2)Circuit protection of power lithium battery pack: Power lithium battery pack needs to be equipped with circuit protection devices to avoid faults or accidents caused by overcharging, overdischarging, overcurrent and other reasons.
(3)Storage and transportation of power lithium battery packs: Power lithium battery packs need to be stored and transported correctly to avoid accidents caused by short circuits, pressure, impact, and other reasons.
(4)Maintenance of Power Lithium Battery Pack: Power lithium battery packs require regular maintenance to ensure their performance and safety.
4 Test
(1)Charge and discharge tests at different temperature
Low temperature charge and discharge performance:
When testing the charge and discharge performance of lithium-ion batteries at room temperature (23 ± 2 ℃) and low temperature (-20 ℃), the following characteristics were found:
During low-temperature charging, the terminal voltage of the battery increases, the charging time decreases, the charging efficiency decreases, and the constant current charging capacity and total charging capacity decrease.
At room temperature, the constant current charging capacity of the battery accounts for 52% of the total charging capacity; At -20 ℃, the proportion is only 6.2%.
At low temperatures, the chemical activity of the active substances in the battery decreases, the solvents in the electrolyte solidify, resulting in reduced ion migration and increased concentration polarization inside the battery, leading to an increase in voltage.
In addition, charging at low temperatures can easily trigger lithium metal dendrite reactions, which may cause lithium metal dendrites to pierce the battery separator and cause internal short circuits, posing certain safety hazards.
High temperature charging and discharging performance:
When testing the charge and discharge performance of lithium-ion batteries at room temperature (23 ± 2 ℃) and high temperature (65 ℃), the following phenomena were observed:
At high temperatures, the charging voltage of the battery rapidly increases to the charging limit voltage, the constant current charging time is significantly shortened, the constant voltage charging time is almost zero, and the entire charging process quickly ends.
After being stored at 65 ℃ for a period of time, the charging capacity of the battery is only 20.8% of room temperature.
This is due to the surface changes of the positive and negative electrode materials of the battery caused by high temperature, the occurrence of side reactions in the electrolyte, and the irreversible changes in the internal structure of the battery caused by the reduction of active lithium, which increases the internal resistance of the battery.
(2)High altitude low-pressure environment simulation test
The battery high-altitude and low-voltage test chamber simulates the low-pressure conditions in a high-altitude environment to conduct a series of tests on the battery. Its core lies in creating a controllable low-pressure environment while maintaining stable parameters such as temperature and humidity to simulate the actual working environment of batteries on high-altitude work platforms such as airplanes and satellites. The test chamber is equipped with a precise pressure control system and temperature and humidity regulation system, which can accurately set and maintain the required testing conditions.
During the testing process, the battery is placed inside the test chamber. By monitoring the changes in voltage, current, temperature and other parameters of the battery under different pressure, the performance of the battery in high-altitude and low-voltage environments can be comprehensively evaluated.
(3)Crush safety test
The principle of lithium battery compression testing is mainly to simulate the compression situations that the battery may encounter during actual use. During testing, the battery is usually placed in a specific device and the squeezing process is simulated by applying a certain amount of pressure. During this process, testers will closely observe the battery’s response, including changes in appearance, temperature, voltage, etc.
The key to crush safety testing is to control the magnitude and speed of the applied pressure to ensure the accuracy and reliability of the test results. At the same time, various safety protection measures need to be taken for the battery during the testing process to prevent possible dangerous situations.
5 Conclusion
As an important component of aircraft power systems, aviation power lithium battery packs have many unique working characteristics, which are of great significance for improving the performance and safety of aircraft. When using power lithium battery packs, attention should be paid to temperature management, circuit protection, storage and transportation, as well as regular maintenance to ensure their safety and performance stability. In the future, research and development of power lithium battery packs will further improve their performance and safety, providing strong support for the development of aircraft power systems.