Why Do Automotive Lithium Batteries Explode?
3 Answers
Automotive lithium batteries can explode due to the following reasons: 1. Insufficient capacity of the lithium-ion battery's negative electrode; 2. Excessive moisture content, which reacts with lithium, causing the battery cell to overcharge and generate gas; 3. Internal short circuit in the battery cell leading to high-current discharge, producing excessive heat and burning the separator; 4. Overcharging of the lithium-ion battery; 5. External short circuit caused by incorrect connection of the positive and negative electrodes. The charging methods for automotive lithium batteries include: 1. For batteries that have been unused for a long time or are new, start with a low-current charge; 2. Use the fast charging method. The charging process for automotive lithium batteries consists of: pre-charging, fast charging, supplementary charging, and trickle charging.
Last time we discussed this in the car enthusiasts group, it was quite interesting. Lithium battery explosions mainly occur during thermal runaway inside the battery, which is when the temperature suddenly spikes uncontrollably. The most common causes are over-discharging during charging or using an external charger with excessive power, leading to lithium-ion crystallization forming dendrites that pierce the separator, causing a direct short circuit and sparking. Physical impacts causing deformation or damage to the battery pack's seal allowing water ingress can also trigger a chain reaction. If the electrolyte leaks and comes into contact with air, it's highly prone to catching fire. Temperature also plays a significant role; cars parked under the scorching sun in summer are particularly at risk. Once a fire starts, it spreads extremely quickly, which is why the underbody protection of new energy vehicles is crucial. However, even with that, serious collisions can still lead to problems.
Having worked in car repairs for over a decade, I've encountered several lithium battery accident cases. Essentially, explosions occur due to the uncontrolled instantaneous release of internal energy within the battery. Common triggers fall into four categories: manufacturing defects, such as impurities in the battery separator or burrs on the electrode edges, which can cause localized overheating during charging; malfunctions in the battery management system leading to overcharging or overdischarging, particularly dangerous during fast charging when voltage and current anomalies occur; physical damage, like undercarriage scrapes causing battery pack deformation and cell compression; and internal structural degradation over time, forming dendrites that pierce the separator. Actual accidents often result from a combination of factors, such as aging battery seals leaking water coupled with a short circuit, causing the organic solvents in the electrolyte to vaporize and explode. It's advisable to regularly inspect the cooling system and the battery's external condition.
