An analysis of optimized series and parallel method for traction lithium-ion batteries

Abstract

Based on the actual operating characteristics of series and parallel batteries, the influences of different pack connection methods on the power ability have been analyzed. Meanwhile, the uneven temperature distribution and imbalanced current phenomenon were described. The results of series cycling tests and parallel cycling tests were studied, which indicate the degradation reasons and fading paths of battery pack. Identification and prediction of operating conditions for different connection methods will significantly extend the lifespan of battery pack. The general control principles obtained from evaluations on the influences of series and parallel components can be used to prolong the cycle life and further optimize the grouping management.

Quantifying cell-to-cell variations of a parallel battery module for different pack configurations

“…SoC inconsistency as well as voltage and resistance can further limit the power availability of a battery pack. The cell with the highest SoC will limit the peak power during charging and the one with the lowest SoC becomes the limiting factor during discharge [16].…”

A Novel Dynamic Performance Analysis and Evaluation Model of Series-Parallel Connected Battery Pack for Electric Vehicles

“…Battery cells are connected in series or parallel, which is the basic connection method, but it is also the main reason for the deterioration of inconsistency between the cells [5]. When packs working at high temperature or high C-rate, their capacity decreases rapidly [5]- [7].…”

“…Battery cells are connected in series or parallel, which is the basic connection method, but it is also the main reason for the deterioration of inconsistency between the cells [5]. When packs working at high temperature or high C-rate, their capacity decreases rapidly [5]- [7]. Besides, the temperature difference among cells in series pack maybe causes safety issues, such as overcharge or over-discharge and increase capacity loss of the pack [6], [8].…”

“…This means that the state of charge (SOC) of the battery cell may be different, even though the cells have the same terminal voltage. The gradually accumulated difference of SOC will lead to a serious imbalance of current at the end of charging or discharging progresses, which will change the temperature of the cells and make cells degrade at different rates [3], [5], [10]- [12]. To avoid dangerous accidents, an effective way to study the performance of the battery pack is to establish a dynamic simulation model of the battery pack.…”

Nominal energy optimisation method of constrained battery packs through the iteration of the series-parallel topology

“…The series‐parallel topology is commonly regarded merely as a means to achieve a minimum requirement of voltage, capacity or power . The number of parallels nP and series nS of a battery pack is normally calculated directly by applying the laws of Kirchhoff and Ohm .…”