1. A physical short circuit occurs when the current collectors at the anode and cathode break through the electrolyte membrane during the lamination and soft packaging process of the battery cell, resulting in physical contact.
2. A chemical short circuit is a localized short circuit caused by chemical changes in the electrode active materials and electrolyte membrane materials during the charge-discharge cycle of a battery cell. Both types of short circuits cause similar battery symptoms, such as abnormal cell formation curves, high self-discharge, battery swelling, and low discharge capacity and charge-discharge efficiency. However, because their short-circuit mechanisms are different, their impact on the battery differs. Generally, when a chemical short circuit occurs inside the battery, not only do the battery's performance become abnormal, but it may also deteriorate rapidly with use. A physical short circuit, on the other hand, does not cause changes in the battery's active materials and electrolyte membrane. When a physical short circuit is not severe, the battery's electrochemical reactions remain essentially unchanged. During formation, some current is lost through the internal physical contact short circuit, causing the actual current density of the cell's active materials to differ from the expected target of the formation process.
polymer lithium-ion battery short circuit
One type is caused by the current collectors at the anode and cathode breaking through the electrolyte membrane during the lamination and soft packaging process of the battery cell, resulting in physical contact and forming a short circuit, which is called a physical short circuit;
Another type is a chemical short circuit, which occurs during the charge-discharge cycle of the battery cell due to chemical changes in the electrode active materials and the electrolyte membrane materials, resulting in localized electron conduction. Both types of short circuits cause similar symptoms in lithium-ion batteries, such as abnormal cell formation curves, high self-discharge, battery bulging, and low discharge capacity and charge-discharge efficiency.
However, because their short-circuit mechanisms are different, the degree of impact on polymer lithium-ion batteries differs. Generally speaking, when a chemical short circuit occurs inside a polymer lithium-ion battery, not only do the battery's various performance characteristics become abnormal, but their performance may also deteriorate rapidly with use.
Physical short circuits are different. The key factors such as the active materials and electrolyte membrane of polymer lithium-ion batteries do not change. When the physical short circuit is not severe, the electrochemical reaction of polymer lithium-ion batteries remains basically unchanged. During formation, some current is lost through the internal physical contact short circuit, which makes the actual current density of the cell's active materials different from the purpose expected by the formation process, resulting in formation abnormalities. During storage and use, the presence of internal circuits leads to large self-discharge, small discharge capacity, and low charge and discharge efficiency.
If the physical short circuit is small enough, the impact of this measured battery anomaly on the use of polymer lithium-ion batteries will be minimal. When the physical short circuit is severe, a large amount of current is lost inside the battery, and the cell will not be able to charge. If this phenomenon occurs after formation, the short circuit overheating will change the electrochemical reaction mechanism inside the battery, and the battery may experience phenomena such as bulging.
