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Uneven electrical current distribution in a parallel-connected lithium-ion battery pack can result in different degradation rates and overcurrent issues in the cells. Understanding the electrical current dynamics can enhance configuration design and battery management of parallel connections.
For parallel-connected battery cells, Offer et al. [ 16] tested a lithium-ion battery pack in a vehicle environment and reported that different inter-cell contact resistances can cause currents to flow unevenly within the pack, leading to cells being unequally loaded.
To maximize battery pack capacity under space and cost constraints, battery cells are often connected in parallel to form battery strings, which become the building blocks for battery modules or packs [ 3].
To meet the power and energy requirements of the specific applications, lithium-ion battery cells often need to be connected in series to boost voltage and in parallel to add capacity . However, as cell performance varies from one to another [2, 3], imbalances occur in both series and parallel connections.
To investigate the influence of cell inconsistency problem in parallel-connected cells, a group of different degraded lithium-ion battery cells were selected to build various battery packs and test them using a battery test bench. The physical model was developed to simulate the operation of the parallel-connected packs.
The battery management system should ensure similar degradation rates for all cells. In contrast, the cells connected in parallel can tolerate some initial variations due to the self-balancing mechanism and they cannot be monitored and controlled as there is no controllability.
The results show that battery configurations with modules directly connected in parallel and then assembled in series are more robust against variation of the cell capacity through the battery.
3 · Designing battery packs is a trade-off between power capability and capacity. Often, high power is only desired for short periods; otherwise, high capacities are preferred. To meet …
3 · Designing battery packs is a trade-off between power capability and capacity. Often, high power is only desired for short periods; otherwise, high capacities are preferred. To meet …
The degradation process of the battery pack and that of individual cells are correlated, however it is said that the pack capacity degradation rate is generally higher than …
chemistries, including different OCV function nonlinearities, on system behavior, and derive analytical bounds on the SOC imbalance using Lyapunov analysis. Keywords: lithium-ion …
The performance of lithium-ion battery modules is highly dependent not only on the thermal management system, but also on the connection design in module formation. …
The results show that battery configurations with modules directly connected in parallel and then assembled in series are more robust against variation of the cell capacity through the battery.
A single cell is not sufficient for some devices. To achieve the desired voltage, the cells are connected in series to add the voltage of cells. To achieve the desired capacity, …
This study reveals why balancing circuits are seldom implemented on cells in a parallel connection, and provides guidance on reducing cell imbalances by managing battery …
For lithium-ion battery packs with cells connected in parallel, a method is provided herein to predict the discharge current of the cells. Based on this method, an …
When nonidentical battery cells are connected in series and parallel to create a pack (see Fig. 1), the system dynamics can no longer be fully understood by studying an …
Here we present an experimental study of surface cooled parallel-string battery packs (temperature range 20–45 °C), and identify two main operational modes; convergent …
Herein, we analyze the cell-to-cell inconsistency and evaluate the comprehensive performance of the air-cooled battery modules with different parallel connection topologies. …
Such differences mean that a certain amount of capacity is not extracted from the in-pack cells. For lithium-ion battery packs with cells connected in parallel, a method is provided herein to predict the discharge current of the …
Here we present an experimental study of surface cooled parallel-string battery packs (temperature range 20–45 °C), and identify two main operational modes; convergent …
For lithium-ion battery packs with cells connected in parallel, a method is provided herein to predict the discharge current of the cells. Based on this method, an …
The charging and discharging characteristics of parallel connection for Lithium iron phosphate (LiFePO 4) battery batteries with constant current and the loop current …
For those willing to put some elbow grease into it, there is an almost unlimited supply of 18650 lithium ion batteries around for cheap (or free) just waiting to be put into a battery pack of some …
To maximize battery pack capacity under space and cost constraints, battery cells are often connected in parallel to form battery strings, which become the building blocks for …
Lithium-ion power batteries are used in groups of series–parallel configurations. There are Ohmic resistance discrepancies, capacity disparities, and polarization differences between individual cells during discharge, …
This study reveals why balancing circuits are seldom implemented on cells in a parallel connection, and provides guidance on reducing cell imbalances by managing battery …
This paper investigated the management of imbalances in parallel-connected lithium-ion battery packs based on the dependence of current distribution on cell chemistries, …
When batteries are connected in parallel, the capacity increases. ... Examples of large battery banks containing 2V lead acid batteries or lithium batteries: ... The longer the cable, the higher …
This paper studies the characteristics of battery packs with parallel-connected lithium-ion battery cells. To investigate the influence of cell inconsistency problem in parallel-connected cells, a …
When assembling lithium-ion cells into functional battery packs, it is common to connect multiple cells in parallel. Here we present experimental and modeling results demonstrating that, when …