Why Does Lithium Battery Life Degrade?
4 Answers
Lithium battery life degrades because lithium ions react with the electrolyte during movement. Lithium batteries are a type of battery that uses lithium metal or lithium alloy as the positive or negative electrode material and employs non-aqueous electrolyte solutions. The functions of the battery are: 1. To supply power to the starting system, ignition system, electronic fuel injection system, and vehicle electrical components when starting the engine; 2. To provide power to the vehicle's electrical equipment when the engine is off or at low idle; 3. To act as a voltage stabilizer for the entire vehicle's electrical system; 4. To store excess electricity generated by the alternator. Methods for maintaining a car battery include: 1. Avoid using car electrical devices after the engine is turned off; 2. Prevent multiple uninterrupted attempts to start the vehicle; 3. Regularly inspect components and connecting circuits; 4. Avoid prolonged parking in open-air parking lots.
The degradation of lithium battery lifespan is primarily caused by internal chemical reactions. As lithium ions continuously move between the positive and negative electrodes during charging and discharging, the electrode materials gradually wear and peel off, similar to how metal fatigues and fractures after repeated bending. Over time, a thin film forms on the electrode surface, called the solid electrolyte interphase (SEI) layer. Initially protective, it thickens over time, blocking ion pathways and consuming more lithium ions. High temperatures accelerate this reaction, causing faster electrolyte decomposition and reduced efficiency. Additionally, frequently draining the battery completely before recharging worsens the degradation process. In automotive applications, these factors collectively lead to reduced range. Therefore, new electric vehicles typically come with battery management systems to control temperature and charge/discharge depth, slowing down degradation and extending the battery's usable life for several more years.
My family's electric car has been in use for several years, and the battery range isn't as good as when it was new. The mechanic told me it's due to lithium battery aging. Every time the battery charges and discharges, lithium ions move back and forth between the electrodes, causing cumulative microscopic damage to the materials. In high-temperature environments, like parking in the sun during summer, internal chemical reactions become more intense, accelerating electrolyte decomposition and shortening the battery's lifespan. Although fast charging saves time, the strong current can overheat and degrade the electrodes more quickly. The mechanic advised me not to drain the battery completely before recharging and to keep it between 20% and 80%. He also warned that poor battery management could lead to the risk of lithium dendrite formation and short circuits. In short, daily usage habits are crucial, and breaking bad habits can save on repair costs.
The decline in lithium battery lifespan is due to chemical fatigue caused by repeated charging and discharging. As lithium ions move in and out of the electrodes, they gradually cause material damage or decomposition, much like how repeated assembly and disassembly of toys can make them loose. High temperatures accelerate reactions, deteriorating the electrolyte faster; low temperatures increase resistance and consume energy. Deep discharges exacerbate degradation, while partial charging is safer. Additionally, self-discharge over time quietly reduces capacity. This type of decay is common in smartphones and electric vehicles. Paying attention to temperature control and small-scale charging can help the battery last longer.
