Analysis of non-safety failure of lithium battery cells

Non-safety failure of the battery will only affect performance. The main points are as follows:

1. Poor capacity consistency:

The inconsistency of power batteries usually means that the remaining battery capacity in a group of batteries is too large and the voltage difference is too large, resulting in shortened battery life. There are many reasons for the poor consistency between batteries, including the battery manufacturing process, the storage time of the battery, the temperature difference during the charging and discharging of the battery pack, and the charging and discharging current.

2. Excessive self-discharge:

The irreversible reaction caused by the micro-short circuit caused by impurities during the battery manufacturing process is the most important reason for the large self-discharge of a single battery. In most battery manufacturers, battery self-discharge can be ignored for a short period of time. Because the battery is charged and discharged for a long time, a large number of self-discharges of the battery are caused by chemical reactions with environmental conditions, which reduces the battery's power and performance, and cannot meet the demand for use.

3. Reduced low-temperature discharge capacity:

With the decrease of temperature, the low-temperature performance of the electrolyte is not good, and the participation in the reaction is not enough. The conductivity of the electrolyte decreases, which leads to an increase in battery resistance, a decrease in voltage platform, and a decrease in capacity.

4. Battery capacity attenuation:

Battery accommodation attenuation mainly comes from the loss of active lithium ions and the loss of electrode active materials. The regularity of the layer structure of the positive electrode active material is reduced, a passivation film is deposited on the negative electrode active material, the degree of graphitization is reduced, and the porosity of the separator is reduced, resulting in an increase in the charge transfer resistance of the battery. The ability to deintercalate lithium is reduced, resulting in a loss of capacity.

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