Valve-regulated lead-acid (VRLA) batteries are widely used in electric power systems due to their reliability and cost-effectiveness. However, their sealed design makes it challenging to accurately assess battery performance during operation, which limits the ability to perform targeted maintenance. This has made the development of advanced battery monitoring systems crucial, especially in power systems where high reliability is essential. Among various testing methods, internal resistance measurement has emerged as one of the most reliable techniques for evaluating battery health. Different failure modes of a battery manifest in distinct internal resistance values, making this parameter key to early fault detection and effective maintenance.
There are two common failure modes that affect VRLA batteries: dehydration and negative plate sulfation. Dehydration occurs when water is lost from the electrolyte, leading to an increase in specific gravity and causing corrosion on the positive grid. This reduces active material and ultimately lowers battery capacity. During charging, oxygen produced at the positive electrode is recombined with the negative electrode, forming water through a process known as cathode absorption. This helps maintain the sealed environment, allowing the battery to be maintenance-free. However, overcharging can cause excessive gas generation, leading to pressure buildup and eventual venting through the safety valve, which results in water loss.
Another major issue is negative plate sulfation, which happens when the battery is not fully charged. Sulfuric acid forms lead sulfate on both electrodes, which can become inactive over time, reducing the battery's overall capacity. To prevent this, batteries must remain fully charged and avoid deep discharges. Similarly, positive plate corrosion can occur due to increased electrolyte acidity from water loss, further degrading battery performance.
Thermal runaway is another critical failure mode, often caused by excessively high float voltages. When the float voltage exceeds 2.25V per cell, the battery may experience a dangerous cycle of increasing temperature and current, eventually leading to swelling, leakage, and failure. Proper voltage management is essential to avoid such scenarios.
In terms of battery modeling, impedance analysis is a widely used technique in electrochemical studies. The battery impedance spectrum typically includes several components: inductance, ohmic resistance, and capacitive elements related to electrode porosity and reaction kinetics. These components help characterize the battery’s internal behavior under different conditions. An equivalent circuit model is often used to represent these effects, including resistances, capacitors, and Warburg impedances, which reflect ion diffusion processes within the battery. Internal resistance, often measured at a fixed frequency, serves as a practical indicator of battery health and is closely linked to its operational state. Understanding these factors is vital for optimizing battery performance, extending service life, and ensuring maximum safety and economic efficiency in power systems.
Lifepo4 Lithium Battery,26650 Battery,3.2V Lifepo4 Lithium-Ion Battery ,26650-3300Mah Battery
Henan Xintaihang Power Source Co.,Ltd , https://www.taihangbattery.com