This paper + presented the design of a constant-current/constant-voltage charging control strategy for a battery cell using the so-called cascade control system arrangement with the adaptation of the battery charging current based on the open-circuit voltage (OCV) parameter estimation.
The relative a) discharge capacity and b) charge capacity of the investigated battery cells. All cells retain around 90 % of the low-current capacity even at the very high discharge currents. During charging, the 85 % of initial capacity is retained for all the cells, except cell 4 (which retains around 65 % of low-current capacity).
These current limits are time dependent and constantly changing. Therefore, current limit estimation or State of Power (SoP) estimation is a continually evolving map. Typically the time window will be from 1 second to 30 seconds for an electric vehicle.
The CLE concept PLE or power limit estimation is widely used to characterize battery state of power, whose main aim is to calculate the limits of a battery operation through the maximum power/current extractable at a particular time point in charge/discharge [15, 29].
The critical variables that limit the charging current corresponding to different SOC intervals are decoupled, and the combined healthy charging protocols satisfying various constraints are derived. Finally, the charging time of the proposed charging protocols and conventional constant current-constant voltage (CC–CV) are compared.
However, precise estimation of state of power remains a challenge because of the highly non-linear behaviour of batteries that are further aggravated at extremities of temperature as well as battery state of charge.