LITHIUM ION BATTERY VOLTAGE CHART
Lithium battery pack voltage range
A fully charged lithium-ion battery typically measures between 4.1V and 4.2V per cell. This voltage range represents 100% state of charge (SOC), and it’s the maximum safe limit for most standard lithium-ion chemistries. Charging beyond this level risks battery damage or safety hazards. [pdf]
Lithium battery pack discharge single string voltage is low
Avoid very deep discharges below 2V or 2.5V, as this quickly and permanently damages a Li-ion battery. Internal metal plating can occur causing a short circuit making the battery unusable and unsafe. [pdf]FAQS about Lithium battery pack discharge single string voltage is low
Can a lithium ion battery pack have multiple strings?
Whenever possible, using a single string of lithium cells is usually the preferred configuration for a lithium ion battery pack as it is the lowest cost and simplest. However, sometimes it may be necessary to use multiple strings of cells. Here are a few reasons that parallel strings may be necessary:
How many volts are in a battery pack?
If each cell is 10 amp hours and 3.3 volts, the battery pack above would be 10 amp hours and 26.4 volts (3.3 volts x 8 cells). For this setup, a BMS capable of monitoring 8 cells in series is necessary. Lithium cells can almost always be paralleled directly together to essentially create a larger cell.
What causes low voltage in a lithium battery?
Root cause 1: High self-discharge, which causes low voltage. Solution: Charge the bare lithium battery directly using the charger with over-voltage protection, but do not use universal charge. It could be quite dangerous. Root cause 2: Uneven current.
Why does a battery pack have a different state of charge?
Additionally, because no two cells are exactly the same, different currents will flow through each battery pack due to differing internal resistances, creating difference in state of charge between the two strings.
How to charge a bare lithium battery?
Solution: Charge the bare lithium battery directly using the charger with over-voltage protection, but do not use universal charge. It could be quite dangerous. Root cause 2: Uneven current. Due to contact resistance or detection of charge, the current is inconsistent caused by the uneven charge of the cell.
How to keep a lithium ion battery balanced?
In Li-ion batteries which have very low self-discharge and therefore accumulative unbalance per cycle is usually less than 0.1%, bypass current of internal FETs is sufficient to keep the pack continuously balanced.
