Yes, when assembling a battery pack for an electric vehicle (EV), it is crucial to ensure that all lithium-ion cells are equally charged before you connect them together. This practice helps achieve balance within the battery pack, thereby extending its overall lifespan and efficiency. It is advisable to use cells of the same make and specifications, and ensure that the connecting wires are of the same length and type. We strongly recommend using busbars for the connections, as they help ensure uniform distribution of current, thus optimizing the performance and safety of the battery pack. Although a Battery Management System (BMS) can balance the cells during operation, the initial balance significantly impacts the effectiveness of the BMS and the lifespan of the battery pack. Therefore, starting with a balanced assembly is essential.