A Designer''s Guide To Lithium Li Ion Battery Charging

Why do lithium-ion batteries deteriorate during fast charging?

During fast charging of lithium-ion batteries (LIBs), cell overheating and overvoltage increase safety risks and lead to faster battery deterioration. Moreover,

What is the capacity loss model for lithium-ion batteries?

For lithium-ion batteries, a simplified capacity loss model was proposed and used to assess the capacity degradation performances for parallel-connected cells. The capacity loss rate increases as the temperature difference between the cells increases.

What happens if a lithium battery is overcharged?

Overcharged cells undergo a rapid decline in capacity due to irreversible lithium plating and side reactions, while chronically undercharged cells risk harmful metallic deposits and voltage reversal. This vicious cycle propagates the imbalance, exacerbating the damage even further.

What happens if a lithium-ion battery is connected parallel?

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.

Why do lithium ion batteries need to be connected in series?

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.

Why are electric bike batteries prone to capacity imbalance?

Take electric bike batteries as an example, since the battery packs of electric vehicles are used in series, they are prone to capacity imbalance after a period of time. Battery cell imbalance occurs when individual cells within a battery pack exhibit different charge levels, capacities or performance.