![]() ![]() The advised charge rate of an Energy Cell is between 0.5C and 1C the complete charge time is about 2–3 hours. In lieu of trickle charge, some chargers apply a topping charge when the voltage drops. Li-ion is fully charged when the current drops to a set level. Full charge is reached when the current decreases to between 3 and 5 percent of the Ah rating.įigure 1: Charge stages of lithium-ion Protection circuits built into the pack do not allow exceeding the set voltage.įigure 1 shows the voltage and current signature as lithium-ion passes through the stages for constant current and topping charge. Boosting the voltage increases capacity, but going beyond specification stresses the battery and compromises safety. Some nickel-based varieties charge to 4.10V/cell high capacity Li-ion may go to 4.30V/cell and higher. ![]() Li-ion with the traditional cathode materials of cobalt, nickel, manganese and aluminum typically charge to 4.20V/cell. Li-ion is a “clean” system and only takes what it can absorb. The so-called miracle charger that promises to prolong battery life and gain extra capacity with pulses and other gimmicks does not exist. While lead acid offers some flexibility in terms of voltage cut off, manufacturers of Li-ion cells are very strict on the correct setting because Li-ion cannot accept overcharge. The differences with Li-ion lie in a higher voltage per cell, tighter voltage tolerances and the absence of trickle or float charge at full charge. The Li ion charger is a voltage-limiting device that has similarities to the lead acid system. (See BU-808b: What causes Li-ion to die?) They blame capacity fade on ions getting trapped, but as with all battery systems, internal corrosion and other degenerative effects also known as parasitic reactions on the electrolyte and electrodes still play a role. This claim carries merits but if the scientists were totally right, then the battery would live forever. Battery scientists talk about energies flowing in and out of the battery as part of ion movement between anode and cathode. Charging and discharging batteries is a chemical reaction, but Li-ion is claimed to be the exception. ![]()
0 Comments
Leave a Reply. |