How to Revive or Charge a Lithium Battery Pack That Has Been Depleted

Renewing a lithium battery that has been depleted from prolonged storage can be a complex process. Is it possible to revive or charge such a battery, or should it be disposed of? This guide will walk you through the steps and conditions necessary to regain performance from your lithium battery for emergency use or repair.

Understanding Lithium Battery Depletion

When a lithium battery is not used for a prolonged period, it tends to degrade. Lithium cells are sensitive to deep discharge conditions. Once a lithium cell is discharged to less than 3V per cell, it typically cannot be revived and must be replaced. Deep discharge can cause permanent damage, as the battery may not be able to hold a charge properly.

Factors That Influence Reviving a Lithium Battery

Factors such as the specific type of lithium cell chemistry and the degree of discharge play crucial roles in whether a lithium battery can be revived. Here is what you need to know:

Lithium Cell Chemistries: Most lithium cell chemistries can tolerate some amount of overdischarging, but the damage can be irreversible if the cell is left discharged for too long.

Overdischarged and Mildly Overdischarged Cells: A mildly overdischarged lithium cell can sometimes be revived. To do this, you can manually apply a charge to the cell until its voltage reaches the minimum level recognized by a standard charger (typically 2.9V-3.2V). However, once the minimum voltage is reached, make sure the charge current is limited to no more than 10% of the cell’s C rating. If the cell heats up or takes notably longer to reach full charge, it is likely damaged and should not be used.

Specific Actions for Different Battery Types

Your Steps: What You Need to Do

If you are dealing with a lithium polymer (LiPoly) cell or pack, it is not recommended to attempt to revive it. These batteries can pose safety risks during the process. Instead, focus on reviving a lithium-ion (Li-ion) battery pack.

For lithium-ion batteries of types such as LCO (Lithium-Cobalt Oxide), NMC (Nickel-Manganese-Cobalt), LFP (Lithium Ferrous Phosphate), and NCA (Cobalt rich Nickel-Manganese-Cobalt), you should try a trickle charge, which means charging the cell at a maximum current of 10 milliamps (0.01 Ampere). Monitor the voltage on the cell throughout the process. If the voltage reaches 3V for standard cells (2V for LFP / LiFePO4), you may continue the charge. If the battery does not reach a charge voltage or does not hold a significant charge, it is considered dead and should be disposed of.

Professional Revival Steps

If you are working with a lithium battery pack and you need to perform a more thorough revival, follow these steps:

Precautions: Ensure that you take safety precautions. Store the battery in a fireproof safe location to prevent any accidents. Assess Voltage: Check the voltage of each cell in the pack. If any cell has a voltage below 1 volt, it is highly likely that it is irreparable. Trickle Charge: Use a low-current method (maximum 10 milliAmps) to trickle charge the battery. Monitor the voltage and wait for it to reach 3V for most lithium-ion cells or 2V for LFP / LiFePO4 cells. This process may take a considerable amount of time. Check After Charging: After the charge is complete, verify that the battery can hold a charge. If it cannot, the battery is considered garbage and should be disposed of properly.

Professional Help

For a detailed and safe revival process, it is recommended to involve a professional who has experience with lithium battery repair and maintenance. They will need specific information about your battery, including its nominal voltage, current voltage, and nominal mAh capacity. They will also need to know what machines the battery is used for.

Once this information is provided, they can advise on the best course of action. You will need a bench power supply with sufficient current capacity, a multimeter for monitoring, and a safe fireproof location for observation.

Note: No liability is assumed for any actions taken based on this advice. Always prioritize safety during the process of reviving or charging lithium batteries.