1、 Parallel charging involves connecting the positive terminal of one battery to the positive terminal of another and the same with the negative terminals. For instance, if one battery fails, it could lead to a severe discharge of the rest of the batteries in the parallel array, potentially resulting in a catastrophic failure， Hence, regular inspection and testing of individual batteries, especially in a large array, is of utmost importance. It’s crucial to ensure that all batteries in the array have the same voltage and capacity to prevent over-discharging or overcharging issues，Despite the advantages, parallel charging of lithium-ion batteries also presents certain challenges.
2、 Lithium-ion batteries have indeed revolutionized energy storage with their high energy density and longevity, but their efficient and safe management, particularly when charging in parallel, necessitates acute understanding and careful handling. The BMS also provides an array of safety features, including overvoltage, under-voltage, and over-current protection, contributing to a safer and more efficient usage， The battery-to-battery tolerance should also be considered, referring to the deviation allowed in the specifications of batteries connected in parallel, and must be kept minimal for the safety of the overall system.
3、 Other considerations include ensuring optimum thermal management, as excessive heat generated during the charging or discharging process can decrease battery performance and lifespan， Consequently, the total capacity is the sum of capacities of individual batteries, while the voltage remains constant.Charging lithium-ion batteries in parallel is a common practice to increase the total energy capacity and extend the overall discharge time while maintaining the same voltage level， The charging rate should also be monitored to avoid damaging the batteries due to rapid charging. Integrated battery management systems (BMS) can assist in maintaining equal charge levels across all cells, thus preventing any potential imbalance.
