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The negative electrode of a drone battery is a key component in the electrochemical system for achieving electrical energy output, directly influencing the battery’s endurance, rate performance, and service life. Its working principle is closely related to electron conduction, ion migration, and chemical reactions. The following explanation is provided from two aspects: structure and charge-discharge mechanism.
I. Structure and Composition of the Negative Electrode and Its Core Functions
In the lithium-ion batteries commonly used in drones, the negative electrode is typically composed of the following parts:
Active material: mainly graphite, with a layered structure that can intercalate lithium ions. Some high-energy batteries use silicon-based materials to increase capacity.
Current collector: Copper foil, with excellent electrical conductivity, is responsible for collecting electrons and conducting them to the external circuit.
Coating structure: The active material is evenly adhered to the copper foil through a binder, forming an efficient reaction interface and enhancing the ion migration efficiency.
Core function: Acting as a “storage depot” for lithium ions and a “channel” for electrons, it enables efficient conversion between electrical energy and chemical energy.
II. The working mechanism of the negative electrode during charging and discharging processes
Discharge phase (during the drone’s flight)
Lithium ion migration: Lithium ions from the positive electrode migrate through the electrolyte to the negative electrode.
Electrical conduction: Electrons flow from the negative terminal to the positive terminal through the external circuit, driving the operation of the flight control system such as the motor.
Negative electrode reaction: Lithium ions are inserted into the graphite layers and combine with electrons to complete the reduction reaction:
Li⁺ + e⁻ + C₆ → LiC₆
At this stage, the negative electrode both releases electrons and receives lithium ions, serving as the starting point of the entire discharge process.
2. Charging phase (when connecting the charger)
External drive: The charger supplies voltage, pushing electrons towards the negative electrode, while lithium ions return from the positive electrode.
Lithium ion insertion and extraction: Lithium ions that are inserted into the graphite layers are extracted and then moved back to the positive electrode through the electrolyte.
Negative electrode reaction: An oxidation reaction occurs, lithium ions are released, and the graphite regains its structure:
LiC₆ → Li⁺ + e⁻ + C₆
At this stage, the negative electrode stores electrons and releases lithium ions, storing energy for the next discharge.
III. Key Characteristics of the Negative Electrode Operation
High reversibility: The lithium ion insertion and extraction processes are stable and reliable, serving as the foundation for the battery’s repeated charging and discharging.
Excellent conductivity: Graphite and copper foil have strong conductivity, which helps reduce internal resistance, enable high-rate discharge, and ensure flight power.
Capacity compatibility: The capacity of the negative electrode is slightly greater than that of the positive electrode, which helps prevent the formation of lithium dendrites and enhances safety and cycle life.
Summary
The negative electrode of the unmanned aerial vehicle battery is the core component that maintains the stability and efficient operation of the entire energy system. Its structural design and material properties directly determine the energy density, rate performance and service life of the battery. The more stable the negative electrode is and the better its conductivity is, the more it can ensure flight safety and endurance performance. It is an indispensable part of the high-performance unmanned aerial vehicle battery system.
