The impact of overcharging and discharging on the safety of lithium battery energy storage power supply

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Safety issues caused by overcharging and discharging of lithium battery energy storage power supply:

When lithium-ion batteries (lithium battery energy storage power sources) are misused or abused, it may lead to overcharging. During overcharging, there is a risk of explosion due to the generation of a large amount of gas inside the battery. When a lithium-ion battery is overcharged, the battery voltage rapidly increases with increasing polarization, causing irreversible changes in the structure of the positive electrode active material and the decomposition of the electrolyte, producing a large amount of gas and releasing a large amount of heat, causing a sharp increase in battery temperature and internal pressure, and posing hidden dangers such as explosion and combustion.

The purpose of testing the overcharging and discharging of lithium battery energy storage power supply:

For the explosion appearance of lithium-ion battery under thermal shock, overcharge, overdischarge, short circuit and other abuse conditions, 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 appliance and current control circuit fail at the same time. If the battery passes this test, it indicates that the chemical design (including electrolyte design, material selection, capacity ratio of positive and negative electrodes, etc.) and structural design in the battery are reasonable.

How to prevent overcharging and discharging of lithium batteries in energy storage power supplies:

1. To prevent overcharging, specialized charging circuits are usually used or safety valves are installed to provide greater overcharging protection.

2. Positive temperature coefficient resistors (PTC) can also be used, which can increase the internal resistance of the battery when overcharging and heating up, limiting the overcharging current.

3. Special separators can also be used. When the temperature of the separator is too high due to abnormal battery conditions, the pores of the separator shrink and block, preventing the migration of lithium ions and overcharging.

4. If a dedicated charger is used for the charging of lithium-ion batteries, the charging voltage is generally limited to 4.2V, and there will be no safety issues with the battery. However, if a dedicated charger is not used, or if the charger fails and causes severe overcharging of the battery, it may cause the battery to catch fire or explode. The charging control of the battery is very important, otherwise there will be serious safety issues.