Cause of Battery Short Circuit
Description
Battery short circuit is usually caused by internal or external factors to directly or indirectly connect the positive and negative electrodes, resulting in a large current,the following are common causes of battery short circuit:
1.Physical damage
1.1 Case failure
The battery is squeezed, dropped, or punctured, resulting in direct contact between the internal positive and negative electrodes, and the metal shell is deformed and in contact with the internal electrodes.
2.2 Diaphragm failure
The diaphragm (the insulating layer separating the positive and negative electrodes) is broken due to high temperature, aging or mechanical damage, so that the positive and negative electrodes are in direct contact.
2.Electrolyte problem
2.1 Electrolyte leakage
The failure of the seal causes the electrolyte to leak, which can corrode the electrode or cause an internal short circuit,the leaking electrolyte reacts with the metal housing to form a conductive substance.
2.2 Electrolyte contamination
Impurities mixed into the electrolyte, reducing the internal resistance, resulting in abnormal current to cause short circuit.
3.Aging and internal failure
3.1 Active material shedding
After long-term use, the electrode material falls off and accumulates, which may penetrate the diaphragm to form a short circuit path.
3.2 Lithium dendrite growth (common in lithium batteries)
When overcharging or fast charging, lithium ions form dendritic crystals (lithium dendrites) on the surface of the negative electrode, which punctures the diaphragm and causes a short circuit.
3.3 Internal short circuit
Production defects (such as electrode misalignment, residual impurities) or internal structural failure after long-term use.
4.Improper use
4.1 Overcharge
The charger fails or is not charged according to the specifications, resulting in increased internal pressure of the battery and damage to the diaphragm.
4.2 Mix different batteries
Old and new batteries, batteries of different capacities or types are mixed, resulting in voltage imbalance and abnormal current.
4.3 Extreme temperature
High temperature accelerates the internal chemical reaction, which may melt the diaphragm; the low temperature causes the electrolyte to freeze, puncturing the diaphragm.
5.External factor
5.1 Metal-conductor contact
Metal items such as coins and keys are accidentally connected to the positive and negative terminals of the battery.
5.2 Humid environment
Water enters the battery or contacts the electrode, forming a conductive path to cause short circuit.
5.3 Polarity inversion
When installing the battery, the positive and negative electrodes are reversed, resulting in abnormal heat in the circuit.