Why does lithium iron phosphate battery bulge?
Overcharging causes lithium battery bulges
Excessive charging of
lithium iron phosphate batteries can cause lithium ions in the positive electrode material to completely enter the positive electrode material, leading to deformation and collapse of the positive electrode, which is the main factor in reducing the capacity of lithium iron phosphate batteries. With the increase in the total number of negative lithium ions, excessive deposition of lithium ions causes them to grow into dendritic crystals, which in turn causes bulges in the lithium battery.
Bulging caused by power loss
When a lithium battery is first charged, the metal electrode reacts with the electrolyte of the
lithium battery, producing a passivation treatment layer that covers the surface of the metal electrode. The passivation treatment film generated can reasonably block the molecular structure in the electrolyte of lithium batteries, but Li+can be freely inserted and adsorbed according to the passivation treatment layer, possessing the characteristics of a solid electrolyte. Therefore, this passivation treatment film is called SEI. The SEI film is not static, and there may be slight changes during battery charging, mainly due to reversible transformation of some organic compounds. Excessive charging and discharging of the lithium iron phosphate battery pack causes irreversible damage to the SEI film, resulting in bulging.
Production and manufacturing level issues
The production and manufacturing level of lithium iron phosphate battery packs is low, which can cause lithium battery bulges, uneven coating of lithium battery grades, and chaotic production processes.
Long term idle
Long term use of lithium iron phosphate batteries can also result in bulging. Due to the conductivity of the gas under certain conditions, prolonged idle time is equivalent to direct contact between the positive and negative electrodes of the battery, leading to long-term short circuit faults.
