Is coulomb counting accurate for estimating SOC of lithium-ion batteries?

The charging and discharging characteristics are investigated and reveal that the coulomb counting method is convenient and accurate for estimating the SOC of lithium-ion batteries. A smart estimation method based on coulomb counting is proposed to improve the estimation accuracy.

Does coulomb counting work with Li-ion batteries?

Using Coulomb Counting to estimate relative SOC changes. Depending on the battery chemistry, Coulomb Counting can be a very accurate technique. On the other side, Coulomb Counting does work as well with Li-Ion batteries, because of their low leakage and good Peukert exponent. Another limitation of Coulomb Counting is drift.

Why is lithium iron phosphate so difficult to measure?

Lithium Iron Phosphate technology has the flattest discharge curve, which makes it very difficult to estimate SoC on a simple voltage measurement. Indeed, the voltage difference between two SoC values may be so small that it is not possible to estimate the state of charge with good precision.

How does coulomb counting work?

Unlike the OCV method, coulomb counting is independent of battery power fluctuations (which cause battery voltage drops), and accuracy remains constant regardless of battery usage.

How to measure lithium ion state of charge (SOC)?

There are several ways to get Lithium-Ion State of Charge (SoC) measurement or Depth of Discharge (DoD) for a lithium battery. Some methods are quite complicated to implement and require complex equipment (impedance spectroscopy or hydrometer gauge for lead acid batteries).

How to calculate SoC for a Li-ion battery?

There is no direct method to calculate SOC for a Li-ion battery but there are several ways in which we can calculate SOC with the help of some additional parameters. The easiest method to calculate the SOC of a battery is by using a battery voltage translation method.