Balancing-Aware Charging Strategy For Series-Connected Lithium-Ion Cells: A Nonlinear Model Predictive Control Approach

Abstract

Charge unbalance is one of the key issues for seriesconnected Lithium-ion cells. Within this context, model-based optimization strategies have proven to be the most effective. In the present paper, an ad-hoc electrochemical model, tailored to control purposes, is firstly presented. Relying on this latter, a general nonlinear MPC for balancing-aware optimal charging is then proposed. In view of the possibility of a practical implementation, the concepts are subsequently specialized for an easily implementable power supply scheme. Finally, the nonlinear MPC approach is validated on commercial cells using a detailed battery simulator, with sound evidence of its effectiveness.

Novel Meta-Heuristic-based Drone Squadron Optimization Fast Charging Strategy for Battery Packs in Electric Vehicles

“…The current owing through the various modules can be drained thanks to the N current generators, I b ,i (t)≥ 0, where i=1,2...N. These current drivers are the system inputs necessary for optimal current regulation of the various cells when operating at constant Ich. Realization of these current generators can be accomplished in several ways, such as by using simple PID controllers to monitor and control the value of a resistive element in parallel with each module, by taking a Pulse Width Modulation (PWM) framework, or by employing a technique using cell bypass via active elements [35].…”

Optimal charging of an electric vehicle battery pack: A real-time sensitivity-based model predictive control approach

“…In this section, the main equations of the simplified electrochemical model proposed in [51] are recalled. The latter consist of a reduction of the P2D [10] model which is detailed but also suitable for control purposes.…”

“…. The scheme in Figure 1 consists also of a supply circuitry which allows approach or a method based on the cell bypass through active elements [51] can be adopted. In this work, the heat generation due to the bypassing process is assumed to be negligible (see [61] for more details on the different supply and balancing circuitry schemes).…”

“…Few works tackle the optimal control of lithium-ion batteries by directly modelling each cell individually. This level of detail is necessary in important tasks such as the model-based State of Charge (SOC) balancing of series-connected cells [46,47,48,49,50,51]. Most of the research produced in this area relies on linear ECMs for each cell (with the exception of [51] which is based on the SP-MeT).…”

“…This level of detail is necessary in important tasks such as the model-based State of Charge (SOC) balancing of series-connected cells [46,47,48,49,50,51]. Most of the research produced in this area relies on linear ECMs for each cell (with the exception of [51] which is based on the SP-MeT). The usage of such models in the battery optimal control context has the advantage of a low computational cost, which allows for real-time implementation even in the case of a high number of cells.…”