4. External Damage and Mechanical Stress
Mechanical damage, whether from physical impacts, vibrations, or incorrect installation, can compromise the structural integrity of LiFePO₄ batteries and lead to safety risks.
- Cause: Mechanical stress can lead to cracked cells, damaged separators, and loss of electrical integrity. When subjected to pressure, cells may short-circuit internally or experience leakage, further increasing the risk of thermal runaway or fire.
- Prevention: To minimize mechanical damage risks, LiFePO₄ batteries should be housed in strong, impact-resistant casings. Additionally, proper installation procedures should be followed to ensure that cells are not subjected to excessive vibration or external forces. For large-scale energy storage systems, vibration dampers and shock-resistant racks can be used to protect batteries from external mechanical stresses.
5. Gas Generation and Leakage
In certain conditions, such as overcharging or overheating, LiFePO₄ batteries can generate gases that accumulate within the cell, leading to internal pressure buildup. If not properly managed, this pressure could cause the cell casing to rupture or lead to a hazardous release of gases.
- Cause: The decomposition of the electrolyte and other cell components can generate gases, including carbon dioxide and other organic compounds. If this buildup is not vented properly, it can lead to swelling, leakage, or rupture.
- Prevention: To prevent gas generation and leakage, modern LiFePO₄ batteries incorporate pressure relief vents that allow the safe escape of gases in case of excessive pressure buildup. Additionally, the BMS should monitor the temperature and pressure within the battery pack to prevent conditions that may lead to dangerous gas accumulation.
6. Internal Cell Imbalance and Aging
Over time, LiFePO₄ batteries may experience internal cell imbalance due to unequal charging or degradation of individual cells. This imbalance can lead to performance issues, and in extreme cases, cause overheating or overvoltage in weaker cells.
- Cause: Uneven aging of cells within a battery pack, due to factors like different charge/discharge cycles, manufacturing defects, or environmental conditions, can cause some cells to degrade faster than others. This results in voltage imbalances that may cause overcharging or overheating of specific cells.
- Prevention: The BMS plays a crucial role in ensuring that cells are balanced during operation. Through active or passive cell balancing, the BMS ensures that all cells in a pack maintain equal voltage, preventing one cell from becoming overcharged or overheated. Regular maintenance and monitoring of battery health are also essential for detecting and addressing imbalances early.
