Safety problems caused by overcharge and overdischarge of lithium battery energy storage power supply:
When lithium ion battery (lithium battery energy storage power supply) is misused or abused, it may lead to overcharge. During overcharge, a large amount of gas is generated inside the battery, which may lead to explosion. When the lithium-ion battery is overcharged, the battery voltage rises rapidly with the increase of polarization, which will cause irreversible changes in the structure of the positive active material and decomposition of the electrolyte, generate a lot of gas, release a lot of heat, make the battery temperature and internal pressure increase sharply, and there are hidden dangers such as explosion and combustion.
Purpose of testing overcharge and overdischarge of lithium battery energy storage power supply:
For the explosion appearance of lithium-ion battery under abuse conditions such as thermal shock, overcharge, overdischarge and short circuit, the overcharge experiment of the battery is an important means to detect the safety performance of the battery. The purpose is to investigate the safety of the battery when the charging apparatus and current control circuit fail at the same time. If the battery passes this test, it shows that the chemical design (including electrolyte design, material selection, capacity ratio of positive and negative electrodes, etc.) and structure design in the battery are reasonable.
How to prevent overcharge and overdischarge of lithium battery of energy storage power supply:
1. In order to prevent overcharging, special charging circuits are usually used or safety valves are installed to provide greater overcharging protection.
2. Positive temperature coefficient resistor (PTC) can also be used. The PTC resistor can make the battery overcharge and increase the internal resistance of the battery when the temperature rises, limiting the overcharge current.
3. A special diaphragm can also be used. When the temperature of the diaphragm is too high due to abnormal battery conditions, the pores of the diaphragm will shrink and block, preventing the migration of lithium ions and overcharge.
4. If a special charger is used for charging the lithium ion battery, the charging voltage is generally limited to 4.2V, and the battery will not have any safety problems. However, if a special charger is not used, or the battery is seriously overcharged due to the failure of the charger, it may cause fire and explosion of the battery. The charging control of the battery is very important, otherwise, there will be serious safety problems