Several criteria should be considered to select the suitable SOC estimation method. First, the SOC and SOH estimation technique could be applied to Li-ion batteries for HEV and EV applications, storage of renewable energy for use at a later time, and energy storage on the grid.
The reliability of the BMS depends on the precision of the state of charge (SOC) estimation of lithium-ion batteries. SOC indicates the remaining capacity and provides an indication of whether the battery needs to be charged or discharged.
There are several ways to get Lithium-Ion State of Charge (SoC) measurement or Depth of Discharge (DoD) of a battery. Main methods are SoC estimation using Open Circuit Voltage Method (OCV) and SoC estimation using Coulomb Counting method.
Battery state of charge (SoC) is an essential aspect of battery management, especially for rechargeable batteries. It refers to the level of charge of a battery relative to its capacity and is usually expressed as a percentage.
Accurate state of charge (SOC) estimation of lithium-ion (Li-ion) batteries is crucial in prolonging cell lifespan and ensuring its safe operation for electric vehicle applications.
Lithium-ion batteries (LiBs) are widely used in electric vehicles (EVs) and energy storage systems due to their high energy density, long life cycle, low self-discharge rate, and so on [1,2].The battery performance is monitored by a battery management system (BMS), in which the SOC is one of the most important status indicators [].Currently, commonly used SOC estimation algorithms include the
Measuring state-of-charge by voltage is simple, but it can be inaccurate because cell materials and temperature affect the voltage. The most blatant error of the voltage-based SoC occurs when disturbing a battery with a charge or discharge.
Low quality cells, lower capacity measured (1.8 Ah) compared to rated (3.2 Ah) Same label as that of manufacturer A. (26650, 5.0 Ah, NMC) Thermal runaway at 15% SOC and higher. Electrolyte leakage and smoke for all tests. (3.3 Ah, NMC) Lower venting temperatures compared to cylindrical cells. Thermal runaway in 40% SOC and higher.
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
What are SoC (state of charge) and SoH (state of health) for a battery? Understanding and monitoring cells'' states, at a particular point in time, is often needed in battery development in order to optimize their use.