Energy storage soc value

What is SOC in lithium ion batteries?

SOC is a significant parameter of lithium-ion batteries and indicates the charge level of a battery cell to drive an EV 4, 5. SOC estimation of lithium-ion batteries is compulsory for the safe and efficient operation of EVs. An accurate SOC estimation method improves the battery lifespan by controlling overcharge and overdischarge states 6.

How accurate is SoC estimation of lithium-ion batteries?

SOC estimation of lithium-ion batteries is compulsory for the safe and efficient operation of EVs. An accurate SOC estimation method improves the battery lifespan by controlling overcharge and overdischarge states 6. However, accuracy of SOC is influenced by electrochemical reactions, material degradation, and aging cycles.

What does SoC mean in a battery?

The SOC of a battery refers to the available state of the remaining charge in the battery, which is generally expressed as a percentage and takes a value in the range of 0 to 1. The classical definition of SOC is shown in Eq. (1). $$SOC=\frac { {Q}_ {remain}} { {Q}_ {rated}}\times 100\%$$

What is a battery voltage vs SoC?

The voltage method converts a reading of the battery voltage to the equivalent SOC value using the known discharge curve (voltage vs. SOC) of the battery. However, the voltage is more significantly affected by the battery current due to the battery’s electrochemical kinetics and temperature.

Which battery cell is used for SOC estimation?

An 18650 NMC cathode-based lithium-ion battery cell with a nominal capacity of 2.0 Ah and a voltage of 3.6 V was used for SOC estimation. Two different patterns of EV drive cycles, namely, DST and FUDS, were utilized to evaluate SOC performance, as depicted in Figs. 4 and 5, respectively.

Why is SoC estimation important?

In fact, precise SOC estimation of the battery can avoid unpredicted system interruption and prevent the batteries from being over charged and over discharged, which may cause permanent damage to the internal structure of batteries.