This self-discharge characteristic further exacerbates imbalances between batteries, posing additional challenges to the battery system. Key Impacts of Battery Disparities. Capacity Limitation: The overall capacity of a battery pack is determined by the cell with the lowest capacity, limiting the output capability in general.
Why is cell balancing important in a battery pack?
When a battery pack is designed using multiple cells in series, it is essential to design the system such that the cell voltages are balanced in order to optimize performance and life cycles. Typically, cell balancing is accomplished by means of by-passing some of the cells during the charge or discharge cycles.
How does battery balancing work?
Battery balancing depends heavily on the Battery Management System. Every cell in the pack has its voltage (and hence SOC) monitored, and when imbalances are found, the pack's SOC is balanced. Passive balancing and active balancing are the two basic approaches to battery balancing.
How can advanced cell balancing improve battery safety and extending battery life?
One of the emerging technologies for enhancing battery safety and extending battery life is advanced cell balancing. Since new cell balancing technologies track the amount of balancing needed by individual cells, the usable life of battery packs is increased, and overall battery safety is enhanced.
From a State of Charge (SOC) perspective, without balancing, the SOC range is typically limited to 20% to 80% for safety reasons, providing only 60% usable capacity. With balancing, the SOC range can be expanded from 5% to 95%, increasing usable capacity to 90%. This means the battery pack's usable capacity is significantly enhanced.
The process typically involves the following steps: Cell monitoring: The battery management system (BMS) continuously monitors the voltage and sometimes temperature of each cell in the pack. Imbalance detection: The BMS identifies cells with higher or lower charge levels compared to the average.
Battery balancing cannot fix a completely dead or damaged cell. Balancing equalizes charge levels among functional cells. If a cell is severely degraded or has failed, you may need to replace it to restore the battery pack's performance.